IOS

iOS
Apple iOS new.svg
IOS 9 Homescreen.png

iOS 9 running on an iPhone 6S
Developer Apple Inc.
Written in C, C++, Objective-C, Swift
OS family Unix-like, based onDarwin (BSD), OS X
Working state Current
Source model Closed source
Initial release June 29, 2007; 8 years ago
Latest release
iPhone 4S or later
iPod Touch (5th generation) or later
iPad 2 or later
iPad Mini (1st generation) or later

9.2.1 (13D20) (February 18, 2016; 1 day ago[1]) [±]

Apple TV (3rd generation)

7.2 (12F69) (April 8, 2015; 10 months ago[2]) [±]

Apple TV (4th generation)

9.2 (13U85) (December 8, 2015; 2 months ago[3]) [±]

Latest preview 9.3 Beta 3 (13E5200d)(February 8, 2016; 11 days ago) [±]
Marketing target Smartphones, tablet computers
Available in 40 languages[4][5][6][7]
Update method iTunes or OTA (iOS 5 or later)
Platforms

Discontinued:

Kernel type Hybrid (XNU)
Default user interface Cocoa Touch (multi-touch, GUI)
License Proprietary softwareexcept for open-source components
Official website www.apple.com/ios/

iOS (originally iPhone OS) is a mobile operating system created and developed by Apple Inc. and distributed exclusively for Apple hardware. It is the operating system that presently powers many of the company’s mobile devices, including the iPhone, iPad, andiPod touch. It is the second most popular mobile operating system platform in the world by sales, after Android.

Originally unveiled in 2007, for the iPhone, it has been extended to support other Apple devices such as the iPod Touch(September 2007), iPad (January 2010), iPad Mini (November 2012) and second-generation Apple TV onward (September 2010). As of January 2015, Apple’s App Store contained more than 1.4 million iOS applications, 725,000 of which are native for iPads.[8]These mobile apps have collectively been downloaded more than 100 billion times.[9]

The iOS user interface is based on the concept of direct manipulation, using multi-touch gestures. Interface control elements consist of sliders, switches, and buttons. Interaction with the OS includes gestures such as swipe, tap, pinch, and reverse pinch, all of which have specific definitions within the context of the iOS operating system and its multi-touch interface. Internalaccelerometers are used by some applications to respond to shaking the device (one common result is the undo command) or rotating it in three dimensions (one common result is switching from portrait to landscape mode).

iOS shares with OS X some frameworks such as Core Foundation and Foundation Kit; however, its UI toolkit is Cocoa Touch rather than OS X’s Cocoa, so that it provides the UIKit framework rather than the AppKit framework. It is therefore not compatible with OS X for applications. Also while iOS also shares the Darwin foundation with OS X, Unix-like shell access is not available for users and restricted for apps, making iOS not fully Unix-compatible either.

Major versions of iOS are released annually. The current release, iOS 9.2, was released on December 8, 2015. In iOS, there are four abstraction layers: the Core OS layer, the Core Services layer, the Media layer, and the Cocoa Touch layer. The current version of the operating system (iOS 9), dedicates around 1.3 GB of the device’s flash memory for iOS itself.[10] It runs on theiPhone 4S and later, iPad 2 and later, iPad Pro, all models of the iPad Mini, and the 5th-generation iPod Touch and later.

History

Original iOS logo, used until 2013 (left) and new logo from 2013 onwards (right)

In 2005, when Steve Jobs began planning the iPhone, he had a choice to either “shrink the Mac, which would be an epic feat of engineering, or enlarge the iPod”. Jobs favored the former approach but pitted the Macintosh and iPod teams, led by Scott Forstalland Tony Fadell, respectively, against each other in an internal competition, with Forstall winning by creating the iPhone OS. The decision enabled the success of the iPhone as a platform for third-party developers: using a well-known desktop operating system as its basis allowed the many third-party Mac developers to write software for the iPhone with minimal retraining.[11] Forstall was also responsible for creating a software developer’s kit for programmers to build iPhone apps, as well as an App Store withiniTunes.[12][13]

The operating system was unveiled with the iPhone at the Macworld Conference & Expo, January 9, 2007, and released in June of that year.[14] At first, Apple marketing literature did not specify a separate name for the operating system, stating simply what Steve Jobs claimed: “iPhone runs OS X” and runs “desktop applications”[15][16] when in fact it runs a variant of [Mac] OS X, that doesn’t run OS X software unless it has been ported to the incompatible operating system. Initially, third-party applications were not supported. Steve Jobs’ reasoning was that developers could build web applications that “would behave like native apps on the iPhone”.[17][18]On October 17, 2007, Apple announced that a native Software Development Kit (SDK) was under development and that they planned to put it “in developers’ hands in February”.[19] On March 6, 2008, Apple released the first beta, along with a new name for the operating system: “iPhone OS”.

On September 5, 2007, Apple released the iPod Touch, which had most of the non-phone capabilities of the iPhone. Apple also sold more than one million iPhones during the 2007 holiday season.[20] On January 27, 2010, Apple announced the iPad, featuring a larger screen than the iPhone and iPod Touch, and designed for web browsing, media consumption, and reading iBooks.[21]

In June 2010, Apple rebranded iPhone OS as “iOS”. The trademark “IOS” had been used by Cisco for over a decade for its operating system, IOS, used on its routers. To avoid any potential lawsuit, Apple licensed the “IOS” trademark from Cisco.[22]

By late 2011, iOS accounted for 60% of the market share for smartphones and tablets.[23] By the end of 2014, iOS accounted for 14.8% of the smartphone market[24] and 27.6% of the tablet and two-in-one market.[25] As of February 2015, StatCounter reported iOS was used on 23.18% of smartphones and 66.25% of tablets worldwide.[26]

Software updates

Main article: iOS version history

Apple provides major updates to the iOS operating system approximately once a year via iTunes and also, for devices that came with iOS version 5.0 or later, over the air. The latest version is iOS 9, which is available for the iPhone 4S, iPhone 5, iPhone 5C, iPhone 5S, iPhone 6, iPhone 6 Plus, iPhone 6S, iPhone 6S Plus, iPad 2, the third and fourth generation iPad, the first and second generation iPad Air, the iPad Pro, the first, second, third and fourth generation iPad Mini, and the fifth and sixth generation iPod Touch. The OS update was released on September 16, 2015.

Before the iOS 4 release in 2010, iPod Touch users had to pay for system software updates. Apple claimed that this was the case because the iPod Touch was not a ‘subscription device’ like the iPhone (i.e., it was a one-off purchase).[27] Apple said it had ‘found a way’ to deliver software updates for free to iPod Touch users at WWDC 2010 when iOS 4 was unveiled.[28]

Features

Home screen

Main article: SpringBoard
iOS 9.1 running on an iPhone (left) and on an iPad Pro (right)

The home screen (rendered by and also known as “SpringBoard“) displays application icons and a dock at the bottom of the screen where users can pin their most frequently used apps. The home screen appears whenever the user unlocks the device or presses the “Home” button (a physical button on the device) whilst in another app.[29] Before iOS 4 on the iPhone 3GS and newer, the screen’s background could be customized with other customizations available through jailbreaking, but can now be changed out-of-the-box. The screen has a status bar across the top to display data, such as time, battery level, and signal strength. The rest of the screen is devoted to the current application. When a passcode is set and a user switches on the device, the passcode must be entered at the Lock Screen before access to the Home Screen is granted.[30]

In iPhone OS 3.0, the Spotlight feature was introduced. It allows users to search media, apps, emails, contacts, messages, reminders, calendar events, and similar content. In iOS 7 and later, Spotlight is accessed by pulling down anywhere on the home screen (except for the top and bottom edges that open Notification Center and Control Center).[31][32] In iOS 9, there are two ways to access Spotlight. As with iOS 7 and 8, pulling down on any homescreen will show Spotlight. However, it can also be accessed as it was in iOS 3 – 6. This gives a Spotlight endowed with Siri suggestions, which include app suggestions, contact suggestions and news.[33]

Since iOS 3.2, users are able to set a background image for the Home screen. This feature is only available on third-generation devices or newer – iPhone 3GS or newer, iPod Touch 3rd generation or newer (iOS 4.0 or later), and all iPad models (iOS 3.2 or later).

Researchers found that users organize icons on their homescreens based on usage-frequency and relatedness of the applications, as well as for reasons of usability and aesthetics.[34]

System font

iOS originally used Helvetica as the system font. With the release of the iPhone 4 and iOS 4, iOS used Helvetica Neue as the system font on devices with Retina Displays, but retained Helvetica as the system font for older devices.[35] iOS 7 provided the ability to scale text in apps or switch to Helvetica Neue Bold as the default system font, as accessibility options. iOS 9 changed the system font to San Francisco, a typeface designed by Apple for maximum legibility on computer and mobile displays, originally introduced as the system font for the Apple Watch.[36]

Folders

With iOS 4 came the introduction of a simple folder system. When applications are in “jiggle mode”, any two (with the exception of Newsstand in iOS 5 and iOS 6, which acts like a folder[37]) can be dragged on top of each other to create a folder, and from then on, more apps can be added to the folder using the same procedure, up to 12 on iPhone 4S and earlier and iPod Touch, 16 on iPhone 5, and 20 on iPad. A title for the folder is automatically selected by the category of applications inside, but the name can also be edited by the user. When apps inside folders receive badges, the numbers shown by the badges is added up and shown on the folder. Folders cannot be put into other folders, though an unofficial workaround exists that enables folders to be nested within folders.[38] iOS 7 updated the folders with pages like on the SpringBoard. Each page can hold nine apps, and the Newsstand app is now able to be placed into a folder.

Notification Center

Main article: Notification Center

Before iOS 5, notifications were delivered in a modal dialog box and could not be viewed after being dismissed. In iOS 5, Apple introduced Notification Center, which allows users to view a history of notifications. The user can tap a notification to open its corresponding app, or clear it.[39] Notifications are now delivered in banners that appear briefly at the top of the screen. If a user taps a received notification, the application that sent the notification will be opened. Users can also choose to view notifications in modal alert windows by adjusting the application’s notification settings. Introduced with iOS 8, widgets are now accessible through the Notification Center, defined by 3rd parties.

When an app sends a notification while closed, a red badge appears on its icon. This badge tells the user, at a glance, how many notifications that app has sent. Opening the app clears the badge.

Accessibility

Located in Settings > General > Accessibility. This allows the user to customize various aspects of the iPhone to assist the user if assistance is needed in the area of seeing or hearing. As well as the addition of accessibility shortcuts.[40]

Included applications

The iOS home screen contains these default “apps”. Some of these applications are hidden by default and accessed by the user through the Settings app or another method—for instance, Nike+iPod is activated through the Settings app. Many of these apps, such as Safari, the App Store, and Siri, can also be disabled in the Restrictions section of the Settings app.[41]

Each table’s green area below shows the iOS version for which each Apple model app feature first became available.

Primary
Series iPhone iPod Touch iPad iPad Mini
Model 1st 3G 3GS 4 4S 5 5C 5S 6 6 Plus 6S 6S Plus 1st 2nd 3rd 4th 5th 6th 1st 2 3rd 4th Air Air 2 1st 2 3
Phone Telephone 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 N/A N/A N/A
Mail Email client 1.1.3 2.1.1 3.1.1 4.1 6.0 8.4 3.2 4.2.1 5.1 6.0 7.0.3 8.1 6.0 7.0.3 8.1
Safari Web browser 1.1
Music Portable media player N/A 5.0 5.0
Videos Video player 3.2 4.2.1
SpringBoard Home screen 1.0 2.0 3.0 4.0
Spotlightsearch 3.0 3.0
Folders N/A 4.0 N/A 4.0 4.2.1
Home screen backgrounds N/A 4.0 N/A 4.0 3.2
Secondary
Series iPhone iPod Touch iPad iPad Mini
Model 1st 3G 3GS 4 4S 5 5C 5S 6 6 Plus 1st 2nd 3rd 4th 5th 6th 1st 2 3rd 4th Air Air 2 1st 2 3
Messages Text messaging 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 N/A N/A N/A
MMS N/A 3.0
iMessageinstant messaging N/A 5.0 N/A 5.0 6.0 5.0 5.1 6.0 7.0.3 8.1 6.0 7.0.3 8.1
Calendar Calendar 1.0 2.0 3.0 4.0 1.1 2.1.1 3.1.1 4.1 3.2 4.2.1
Photos Photo viewer
Video viewer 2.0 2.0
Crop, red eye fix, auto enhance and photo rotate N/A 5.0 N/A 5.0 N/A 5.0
Camera Camera 1.0 2.0 3.0 4.0 N/A 4.1 N/A 4.2.1
Camcorder N/A
Auto-focus 3.0 4.0 N/A N/A
HDR N/A 4.1
Crop, red eye fix, auto enhance and photo rotate 5.0 5.0 5.0
Panorama N/A 6.0 N/A N/A 8.0 N/A 8.0
Take still photos while recording video N/A N/A N/A N/A
Photo filters 7.0 7.0
Burst mode N/A 7.0 N/A
FaceTime Video calling over Wi-Fi N/A 4.0 5.0 6.0 7.0 N/A 4.1 6.0 4.2.1 5.1 6.0 7.0.3 8.1 6.0 7.0.3 8.1
Video calling over 3G/LTE (iPad requires a cellular network) N/A 6.0 N/A N/A N/A 6.0 6.0.1 6.0.1
FaceTime Audio 7.0 7.0 7.0 7.0
Photo Booth A camera application with added special effects N/A N/A 4.2.1 5.1 6.0 6.0
Stocks Stocks provided byYahoo! Finance 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 1.1.3 2.1.1 3.1.1 4.1 6.0 N/A N/A
Stocks Widget for Notification Center N/A 5.0 N/A 5.0
Weather Weather provided byThe Weather Channel N/A 8.0 N/A 8.0
Weather Widget forNotification Center 5.0 5.0 6.0 7.0 8.0 5.0 6.0 N/A 7.0 7.0.3 8.1 7.0 7.0.3 8.1
Notes A simple note-taking program 1.0 2.0 3.0 4.0 1.1.3 2.1.1 3.1.1 4.1 3.2 4.2.1 5.1 6.0 6.0
Maps Assisted GPS(iPad requires a cellular network) N/A N/A 6.0.1 6.0.1
Apple-sourced maps N/A 6.0 N/A 6.0 6.0 N/A 6.0 6.0
Turn-by-turn navigationusing Apple-sourced maps N/A 6.0 N/A
Reminders A to-do list application N/A 5.0 5.0 5.0 N/A 5.0 5.0 5.1 6.0 6.0
Location-based reminders (iPad requires a cellular network) N/A N/A N/A 6.0.1 6.0.1
Voice Memos Voice recorder 3.0 3.0 4.0 3.0 3.1.1 4.1 6.0 N/A N/A
Calculator Calculator 1.0 2.0 1.1 2.1.1
Scientific calculator (triggered by rotating to landscape) 2.0 2.0
Clock World clock,stopwatch,alarm clockand timer 1.0 1.1 N/A 6.0 7.0.3 8.1 6.0 7.0.3 8.1
Settings Settings 3.2 4.2.1 5.1 6.0
Contacts Standalone address/phone book 2.0
iTunes Store Access to the iTunes Store and iTunes Podcast Directory 1.1
App Store To buy or get iOS apps 2.0 2.0
Compass Compass N/A N/A N/A N/A
Game Center Play multiplayer games with other users,
track in-game achievements, view leaderboards.
4.1 8.0 N/A 4.1 6.0 4.2.1 4.2.1 5.1 6.0 7.0.3 8.1 6.0 7.0.3 8.1
Voice Control Simple voice control (disabling Siri may be necessary) 3.0 4.0 N/A 3.1.1 4.1 N/A N/A
Siri A personal voice assistant N/A N/A N/A 6.0 6.0 7.0.3 8.1 6.0 7.0.3 8.1
Voice dictation 5.1
Touch ID A fingerprint recognitionfeature built into the home button;
able to unlock the device and make iTunes/App Store purchases
N/A 7.0 N/A N/A N/A
Wallet A virtual wallet application for passes, tickets, coupons and loyalty cards (called Passbook prior to iOS 9) N/A 6.0 7.0 N/A 6.0 N/A N/A
CarPlay A new in-vehicle extended iOS functionality N/A 7.1.1 N/A
AirDrop An ad-hoc Wi-Fi/Bluetooth-based file sharing mechanism N/A 7.0 N/A 7.0 N/A 7.0 8.1 7.0 8.1
Health An app that monitors and analyzes an individual’s biochemistry and physiology N/A 8.0 N/A 8.0 N/A N/A
Tips An app that gives tutorials for various functions N/A 8.0 8.0
Podcasts Integrated podcast player
iBooks Integrated e-book viewer
News N/A 9.0 N/A 9.0 N/A 9.0 9.0
Find My iPhone
Find My Friends
iCloud Drive (turned off by default – can be enabled in Settings)
Discontinued
Series iPhone iPod Touch iPad iPad Mini Final supported
iOS version
Model 1st 3G 3GS 4 4S 5 5C 5S 6 6 Plus 1st 2nd 3rd 4th 5th 6th 1st 2 3rd 4th Air Air 2 1st 2 3
iPod iPhone media player, iPad music player 1.0 2.0 3.0 4.0 N/A N/A 3.2 4.2.1 N/A N/A 4.2.10(CDMA)
4.3.5
YouTube YouTubevideo streamer 5.0 N/A 1.1 2.1.1 3.1.1 4.1 N/A 5.1 N/A 5.1.1
Maps Google Maps withGoogle Street View 1.1.3
Weather Weather provided by Yahoo!Weather 6.0 7.0 N/A 6.0 N/A N/A 7.1.2
Nike + iPod Records the distance and pace of a walk or run; can connect to Nike + iPod sensor (turned off by default – can be enabled in Settings) N/A N/A 8.4.1
Newsstand A newspaper and magazine store N/A 8.0 N/A 5.0 8.4 N/A 5.1 6.0 7.0.3 8.1 6.0 7.0.3 8.1

On the iPhone and iPod Touch, apps such as Voice Memos, Contacts, Calculator, and Compass are in one folder called “Utilities” in iOS 4 and above.[42][43] Many of the included applications are designed to share data (e.g., a phone number can be selected from an email and saved as a contact or dialed for a phone call). For the iOS 7 update, the folder name was changed to “Extras”.

The Messages app supports Apple’s iMessage service in iOS 5 or above; iMessage supports sending free text or multimedia messages to other iOS devices running iOS 5 and above (similar to BlackBerry Messenger), and to Macs running OS X Mavericks.

Panoramic photography is available only on iPhone 4S and later models, and the fifth generation iPod Touch.[44][45]

The bottom row of applications, called the dock, is used to delineate the iPhone’s main purposes: originally Phone, Mail, Safari, iPod. Starting with iOS 5, the iPod app was split into two apps, Music and Videos, as it always has been on the iPod Touch, and the Music app replaced the iPod app in the dock.

Since the inception of the iPhone, various apps were either integrated into iOS (e.g. Podcasts, iBooks, Siri, Facebook, Twitter) or disintegrated (e.g. Podcasts, iTunes U, YouTube). In iOS 6, the previously integrated YouTube app was removed from the software, and moved to the App Store. The Podcasts and iTunes U features (previously integrated in the Music and Videos apps) also became their own apps in the App Store. In iOS 7, the iPhone gains a dedicated FaceTime app (previously integrated into the Phone app), as it had been on the iPod Touch and iPad since iOS 4. In iOS 8, the iBook and Podcast apps became integrated into iOS, though the App Store app is still available for download. In iOS 9, the Find My iPhone and Find My Friends became integrated into iOS; App Store versions are unavailable for download.

Starting January 2008, the iPod Touch retains the same applications that are present by default on the iPhone, with the exception of the Phone and Compass (and also previously, Messages before iOS 5 and Camera before the fourth-generation iPod Touch) apps. The original dock layout was Music, Videos, Photos, and iTunes. In iPhone OS 3, the layout was changed to Music, Videos, Safari, and App Store. For the fourth-generation iPod Touch, it includes FaceTime and Camera, and the dock layout had changed to Music, Mail, Safari, Videos, with the release of iOS 4. With the release of the new fifth-generation iPod Touch and iOS 6, the dock layout was changed to Messages, Mail, Safari, Music, similar to the iPhone.

The iPad and iPad Mini come with the same applications as the iPod Touch, excluding Stocks, Weather, Calculator, and the Nike + iPod app (and also previously, Clock before iOS 6). Additionally, starting with the iPad 2, they have the unique Photo Booth app. Most of the default applications, such as Safari and Mail, are completely rewritten to take advantage of the iPad’s and iPad Mini’s larger displays. The original dock layout was Safari, Mail, Photos, iPod. Separate music and video apps are provided, as on the iPod Touch, although (as on the iPhone) the music app was named “iPod”. In iOS 5, it was changed to “Music” and the dock layout became Safari, Mail, Photos, Music. In iOS 6, Videos replaced Photos in the dock. In iOS 7, the default dock layout was changed to match that of the iPod Touch.

Multitasking

Multitasking for iOS was first released in June 2010 along with the release of iOS 4.0.[46][47] Only certain devices—iPhone 4, iPhone 3GS, and iPod Touch 3rd generation—were able to use multitasking.[48] The iPad did not get multitasking until the release of iOS 4.2.1 in November 2010.[49] Currently, multitasking is supported on iPhone 3GS or newer, iPod Touch 3rd generation or newer, and all iPad models.[50]

Implementation of multitasking in iOS has been criticized for its approach, which limits the work that applications in the background can perform to a limited function set and requires application developers to add explicit support for it.[48][51]

Before iOS 4, multitasking was limited to a selection of the applications Apple included on the device. Users could, however “jailbreak” their device in order to unofficially multitask.[52] Starting with iOS 4, on third-generation and newer iOS devices, multitasking is supported through seven background APIs:[53]

  1. Background audio – application continues to run in the background as long as it is playing audio or video content[54]
  2. Voice over IP – application is suspended when a phone call is not in progress[54]
  3. Background location – application is notified of location changes[54]
  4. Push notifications
  5. Local notifications – application schedules local notifications to be delivered at a predetermined time[54]
  6. Task completion – application asks the system for extra time to complete a given task[54]
  7. Fast app switching – application does not execute any code and may be removed from memory at any time[54]

In iOS 5, three new background APIs were introduced:

  1. Newsstand – application can download content in the background to be ready for the user[54]
  2. External Accessory – application communicates with an external accessory and shares data at regular intervals[54]
  3. Bluetooth Accessory – application communicates with a bluetooth accessory and shares data at regular intervals[54]

In iOS 7, Apple introduced a new multitasking feature, providing all apps with the ability to perform background updates. This feature prefers to update the user’s most frequently used apps and prefers to use WiFi networks over a cellular network, without markedly reducing the device’s battery life.

Switching applications

In iOS 4.0 to iOS 6.x, double-clicking the home button activates the application switcher. A scrollable dock-like interface appears from the bottom, moving the contents of the screen up. Choosing an icon switches to an application. To the far left are icons which function as music controls, a rotation lock, and on iOS 4.2 and above, a volume controller.

With the introduction of iOS 7, double clicking the home button also activates the application switcher. However, unlike previous versions it displays screenshots of open applications on top of the icon and horizontal scrolling allows for browsing through previous apps, and it is possible to close applications by dragging them up, similar to howWebOS handled multiple cards.[55]

With the introduction of iOS 9, the application switcher received a significant visual change; whilst still retaining the card metaphor introduced in iOS 7, the application icon is smaller, and appears above the screenshot (which is now larger, due to the removal of “Recent and Favorite Contacts”), and each application “card” overlaps the other, forming arolodex effect as the user scrolls. Now, instead of the home screen appearing at the leftmost of the application switcher, it appears rightmost.[56]

Ending tasks

In iOS 4.0 to iOS 6.x, briefly holding the icons in the application switcher makes them “jiggle” (similarly to the homescreen) and allows the user to force quit the applications by tapping the red minus circle that appears at the corner of the app’s icon.[57] Clearing applications from multitasking stayed the same from iOS 4.0 through 6.1.6, the last version of iOS 6.

As of iOS 7, the process has become faster and easier. In iOS 7, instead of holding the icons to close them, they are closed by simply swiping them upwards off the screen. Up to three apps can be cleared at a time compared to one in versions up to iOS 6.1.6.[58]

Task completion

Task completion allows apps to continue a certain task after the app has been suspended.[59][60] As of iOS 4.0, apps can request up to ten minutes to complete a task in the background.[61] This doesn’t extend to background up- and downloads though (e.g. if you start a download in one application, it won’t finish if you switch away from the application).

Siri

Main article: Siri (software)

Siri is a personal assistant and knowledge navigator which works as an application on supported devices. The service, directed by the user’s spoken commands, can do a variety of different tasks, such as call or text someone, open an app, search the web, lookup sports information, find directions or locations, and answer general knowledge questions (e.g. “How many cups are in a gallon?”).[62] Siri was updated in iOS 7 with a new interface, faster answers, Wikipedia, Twitter, and Bing support and the voice was changed to sound more human. Siri is currently only available on the iPhone 4S and later iPhones, the fifth and sixth generation iPod Touch, all of the models of the iPad Mini, and the third-generation and later iPads.

Game Center

Main article: Game Center

Game Center is an online multiplayer “social gaming network”[63] released by Apple.[64] It allows users to “invite friends to play a game, start a multiplayer game through matchmaking, track their achievements, and compare their high scores on a leaderboard.” iOS 5 and above adds support for profile photos.[63]

Game Center was announced during an iOS 4 preview event hosted by Apple on April 8, 2010. A preview was released to registered Apple developers in August.[63] It was released on September 8, 2010 with iOS 4.1 on iPhone 4, iPhone 3GS, and iPod Touch 2nd generation through 4th generation.[65] Game Center made its public debut on the iPad with iOS 4.2.1.[66] There is no support for the iPhone 3G, original iPhone and the first-generation iPod Touch (the latter two devices did not have Game Center because they did not get iOS 4). However, Game Center is unofficially available on the iPhone 3G via a hack.[67]

Development

Authorized third-party native applications are available through Apple’s App Store for devices running iPhone OS 2.0 and higher. Native apps must be written in Swift or Objective-C (with some elements optionally in C or C++) and compiled specifically for iOS and the 64-bit ARM architecture or previous 32-bit one (typically using Xcode). Third-party attemptshave been made to allow apps written with Java, .NET, and Adobe Flash to run on iOS devices, but due to Apple restrictions these are generally not available in the iOS App Store.

The Safari web browser supports web applications as with other web browsers. Hybrid apps embed a mobile web site inside a native app, possibly using a hybrid framework likeApache Cordova or React Native.

SDK

Main article: iOS SDK

iOS SDK 9.1 included in Xcode 7.1

On October 17, 2007, in an open letter posted to Apple’s “Hot News” weblog, Steve Jobs announced that a software development kit (SDK) would be made available to third-party developers in February 2008.[68] The SDK was released on March 6, 2008, and allows developers to make applications for the iPhone and iPod Touch, as well as test them in an “iPhone simulator”. However, loading an application onto the devices is only possible after paying an iPhone Developer Program fee.

The fees to join the respective developer programs for iOS and OS X were each set at US$99.00 per year. As of July 20, 2011, Apple released Xcode on its Mac App Store free to download for all OS X Lion users, instead of as a standalone download. Users can create and develop iOS and OS X applications using a free copy of Xcode; however, they cannot test their applications on a physical iOS device, or publish them to the App store, without first paying the yearly $99.00 iPhone Developer or Mac Developer Program fee.[69]

Since the release of Xcode 3.1, Xcode is the development environment for the iOS SDK.

Developers are able to set any price above a set minimum for their applications to be distributed through the App Store, keeping 70% for the developer, and leaving 30% for Apple. Alternatively, they may opt to release the application for free and need not pay any costs to release or distribute the application except for the membership fee.[70]

Market share

iOS is the second most popular mobile operating system platform in the world by sales, after Android.

By the middle of 2012, there were 410 million devices activated.[71] At WWDC 2014, Tim Cook said 800 million devices had been sold by June 2014.[72]

During Apple’s quarterly earnings call in January 27, 2015, Apple announced that they have now sold one billion iOS devices since 2007[73] (a little less than Android sold in 2014 only[74]).

Jailbreaking

Main article: iOS jailbreaking

Since its initial release, iOS has been subject to a variety of different hacks centered around adding functionality not allowed by Apple.[75] Prior to the 2008 debut of Apple’s nativeiOS App Store, the primary motive for jailbreaking was to bypass Apple’s purchase mechanism for installing the App Store’s native applications.[76] Apple claimed that it will not release iOS software updates designed specifically to break these tools (other than applications that perform SIM unlocking); however, with each subsequent iOS update, previously un-patched jailbreak exploits are usually patched.[77]

Since the arrival of Apple’s native iOS App Store, and—along with it—third-party applications, the general motives for jailbreaking have changed.[78] People jailbreak for many different reasons, including gaining filesystem access, installing custom device themes, and modifying the device SpringBoard. An additional motivation is that it may enable the installation of pirated apps. On some devices, jailbreaking also makes it possible to install alternative operating systems, such as Android and the Linux kernel. Primarily, users jailbreak their devices because of the limitations of iOS. Depending on the method used, the effects of jailbreaking may be permanent or temporary.[79]

In 2010, the Electronic Frontier Foundation (EFF) successfully convinced the U.S. Copyright Office to allow an exemption to the general prohibition on circumvention of copyright protection systems under the Digital Millennium Copyright Act (DMCA). The exemption allows jailbreaking of iPhones for the sole purpose of allowing legally obtained applications to be added to the iPhone.[80] The exemption does not affect the contractual relations between Apple and an iPhone owner, for example, jailbreaking voiding the iPhone warranty; however, it is solely based on Apple’s discretion on whether they will fix jailbroken devices in the event that they need to be repaired. At the same time, the Copyright Office exempted unlocking an iPhone from DMCA’s anticircumvention prohibitions.[81] Unlocking an iPhone allows the iPhone to be used with any wireless carrier using the same GSM or CDMA technology for which the particular phone model was designed to operate.[82]

Unlocking

Main article: SIM lock

Initially most wireless carriers in the US did not allow iPhone owners to unlock an iPhone for use with other carriers. However AT&T Mobility allowed iPhone owners who have satisfied the requirements of their contract to unlock their iPhone.[83] Instructions to unlock the device are available from Apple,[84] but it is ultimately the sole discretion of the carrier to authorize the device to be unlocked.[85] This allows the use of a carrier sourced iPhone on other networks. However, because T-Mobile primarily uses a different band than AT&T for its 3G data signals, the iPhone will only work at 3G speeds on the T-Mobile 1900 MHz network.[86] There are programs to break these restrictions, but are not supported by Apple and most often not a permanent unlock, known as soft-unlock.[87]

Digital rights management

The closed and proprietary nature of iOS has garnered criticism, particularly by digital rights advocates such as the Electronic Frontier Foundation, computer engineer and activistBrewster Kahle, Internet-law specialist Jonathan Zittrain, and the Free Software Foundation who protested the iPad’s introductory event and have targeted the iPad with their “Defective by Design” campaign.[88][89][90][91] Competitor Microsoft, via a PR spokesman, criticized Apple’s control over its platform.[92]

At issue are restrictions imposed by the design of iOS, namely digital rights management (DRM) intended to lock purchased media to Apple’s platform, the development model (requiring a yearly subscription to distribute apps developed for the iOS), the centralized approval process for apps, as well as Apple’s general control and lockdown of the platform itself. Particularly at issue is the ability for Apple to remotely disable or delete apps at will.

Some in the tech community have expressed concern that the locked-down iOS represents a growing trend in Apple’s approach to computing, particularly Apple’s shift away from machines that hobbyists can “tinker with” and note the potential for such restrictions to stifle software innovation.[93][94] Former Facebook developer Joe Hewitt protested against Apple’s control over its hardware as a “horrible precedent” but praised iOS’s sandboxing of apps.[95]

Kernel

The iOS kernel is XNU, the kernel of Darwin. The original iPhone OS (1.0) up to iPhone OS 3.1.3 used Darwin 9.0.0d1. iOS 4 was based on Darwin 10. iOS 5 was based on Darwin 11. iOS 6 was based on Darwin 13. iOS 7 and iOS 8 are based on Darwin 14. iOS 9 is based on Darwin 15.[96]

Devices

Main article: List of iOS devices
Apple TV iPad Mini 4 iPad Mini 3 iPad Mini 2 iPad Mini (1st generation) iPad Pro iPad Air 2 iPad Air iPad (4th generation) iPad (3rd generation) iPad (2nd generation) iPad (1st generation) iPod Touch (6th generation) iPod Touch (5th generation) iPod Touch#Models iPod Touch#Models iPod Touch#Models iPod Touch#Models IPhone 6S IPhone 6S iPhone 6 Plus iPhone 6 iPhone 5S iPhone 5C iPhone 5 iPhone 4S iPhone 4 iPhone 3GS iPhone 3G iPhone (1st generation)

Sources: Apple press release library,[97] Mactracker Apple Inc. model database[98]

See also

References

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    Available in iOS 8 and iOS 9 via Privacy > Diagnostics & Usage > Diagnostics & Usage Data > JetsamEvent-(date and time).ips, when low in memory
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Further reading

  • Hillegass, Aaron; Conway, Jon (March 22, 2012). iOS Programming: The Big Nerd Ranch Guide (3rd ed.). Pearson. p. 590. ISBN 978-0-321-82152-2.
  • Turner, Kirby (December 19, 2011). Learning iPad Programming: A Hands-on Guide to Building iPad Apps with iOS 5 (1st ed.). Pearson. p. 816. ISBN 978-0-321-75040-2.
  • Mark, Dave; LaMarche, Jeff (July 21, 2009). Beginning iPhone 3 Development: Exploring the iPhone SDK (1st ed.). Apress. p. 584. ISBN 1-4302-2459-2.
  • Mark, Dave; LaMarche, Jeff (December 29, 2009). More iPhone 3 Development: Tackling iPhone SDK 3 (1st ed.). Apress. p. 552. ISBN 1-4302-2505-X.

Android

Android
Android robot.svgAndroid logo (2014).svg
Android 6.0-en.png
Домашний экран Android 6
Разработчик Android Inc, Google,
Open Handset Alliance
Семейство ОС Linux
Основана на ядро Linux
Исходный код свободное и открытое программное обеспечение,проприетарные драйверы
Первый выпуск 23 сентября 2008
Последняя версия 6.0.1 Marshmallow (8 декабря 2015)
Менеджеры пакетов Google Play, Яндекс.Store,Amazon Appstore, GALAXY Apps и др.
Поддерживаемые языки русский, английский и ещё более 100 языков
Поддерживаемые платформы 32-битные и 64-битные: ARM,MIPS, x86
Тип ядра монолитноемодифицированное ядро Linux
Лицензия Apache v2 — пространство пользователя,
GPL v2 — патчи ядра Linux[1]
Состояние Активное
Веб-сайт android.com

Android («Андро́ид»[ком. 1]) — операционная система для смартфонов, интернет-планшетов, электронных книг,цифровых проигрывателей, наручных часов, игровых приставок, нетбуков, смартбуков, очков Google[2], телевизоров[3] и других устройств. В будущем планируется поддержка автомобилей[4] и бытовых роботов. Основана на ядре Linux[5] и собственной реализации виртуальной машины Java от Google. Изначально разрабатывалась компанией Android Inc., которую затем купила Google. Впоследствии Google инициировала создание альянса Open Handset Alliance (OHA), который сейчас занимается поддержкой и дальнейшим развитием платформы. Android позволяет создавать Java-приложения, управляющие устройством через разработанные Google библиотеки. Android Native Development Kit позволяет портировать библиотеки и компоненты приложений, написанные на Си и других языках.

В 86 % смартфонов, проданных во втором квартале 2014 года, была установлена операционная система Android[6]. При этом за весь 2014 год было продано более 1 миллиарда Android-устройств[7].

В июле 2005 года корпорация Google купила компанию Android Inc.[8] 5 ноября 2007 года компания официально объявила о создании Open Handset Alliance (OHA) и анонсировала открытую мобильную платформу Android[9], а 12 ноября 2007 года альянс представил первую версию пакета для разработчиков Android «Early Look» SDK и эмулятор Android[8][10].

23 сентября 2008 года официально вышла первая версия операционной системы, а также первый полноценный пакет разработчика SDK 1.0, Release 1[11][12]. С момента выхода первой версии платформы произошло несколько обновлений системы. Эти обновления, как правило, касаются исправления обнаруженных ошибок и добавления новой функциональности в систему.

В 2009 году было представлено целых четыре обновления платформы. Так, в феврале вышла версия 1.1 с исправлением различных ошибок[13]. В апреле[14] и сентябре[15] вышли ещё два обновления — 1.5 «Cupcake» и 1.6 «Donut» соответственно. Обновление «Cupcake» привнесло существенные изменения: виртуальная клавиатура, воспроизведение и запись видео, браузер и другие[16]. В «Donut» впервые появились поддержка различных разрешений и плотности экрана и сетей CDMA[13]. В октябре того же года вышла версия операционной системы Android 2.0 «Eclair»[17] с поддержкой нескольких аккаунтов Google, поддержкой браузером языка HTML5 и других нововведений, а также после небольшого обновления в пределах версии «Eclair» (2.1) появились «живые обои» и был видоизменён экран блокировки[13].

В середине 2010 года[18] Google представила Android версии 2.2 под наименованием «Froyo», а в конце[19] 2010 года — Android 2.3 «Gingerbread». После обновления «Froyo» стало возможно использовать смартфон в качестве точки доступа, использовать традиционную блокировку смартфона цифровым или буквенно-цифровым паролем и другие изменения, а обновление «Gingerbread» привнесло более полный контроль над функцией копирования и вставки, улучшение управления питанием и контроля над приложениями, поддержку нескольких камер на устройстве и т. д.[13]

22 февраля 2011 года[20] была официально представлена ориентированная на интернет-планшеты платформа Android 3.0 «Honeycomb»[21].

Android 4.0 «Ice Cream Sandwich», вышедшая 19 октября 2011 года[22], — первая универсальная платформа, которая предназначена как для планшетов, так и для смартфонов[23][24]. Также обновление привнесли новый интерфейс «Holo», который использовался до Android 4.4.4 KitKat, на данный момент заменен на Material Design(Android 5).

В июне 2012 вышло обновление под названием «Jelly Bean» с порядковым номером 4.1[25], который сменился на 4.2 вследствие небольшого обновления в конце октября того же года[26] и на 4.3 после обновления в июле 2013[27].

31 октября 2013 года Google представила следующую версию операционной системы Android 4.4, которая получила название шоколадного батончика «KitKat» по соглашению с компанией производителем Nestlé[28]. Впервые KitKat появился на Nexus 5; эта версия Android оптимизирована для работы на более широком наборе устройств, имеющих 512 МБ ОЗУ в качестве рекомендуемого минимума.

25 июня 2014 Google представили Android L, доступный для разработчиков, пользователей смартфонов Nexus а также некоторых других смартфонах[29].

В 2014 году была анонсирована операционная система для носимых устройств Android Wear. Также на Google I/O были представлены версии Android Auto (для автомобилей) и Android TV (для телевизоров), тем самым Android перестал быть операционной системой только для мобильных устройств.

15 октября 2014 года была официально анонсирована Android 5.0 Lollipop. Главное обновление системы — новый дизайн Material design. Также, если на Android-устройстве установлен пароль или графический ключ, и если поблизости находятся часы хозяина устройства с Android Wear, то устройство автоматически разблокируется.

9 декабря 2014 Googlе заменила официальную среду разработки, основанную на Eclipse (adt-bundle), на Android Studio.[30][31]

29 мая 2015 Googlе представила Android M. По словам Google главная цель новой операционной системы — улучшить пользовательский опыт общения со смартфоном, сделать взаимодействие интуитивнее и проще[32]

17 августа 2015 официально стало известно, что Android M получила название Android 6.0 Marshmallow[33]

Применение[править | править вики-текст]

HTC Dream (T-Mobile G1) — первый смартфон на базе ОС Android

Рабочий стол ОС Android 1.5 в эмуляторе

Первым устройством, работающим под управлением Android, стал разработанный компанией HTC смартфон HTC Dream(официально выпущен сотовым оператором T-Mobile под названием T-Mobile G1), презентация которого состоялась 23 сентября 2008 года[34]. Вскоре последовали многочисленные заявления других производителей смартфонов о намерении выпустить устройства на базе Android. В России первым Android-смартфоном, поступившим в продажу (июль 2009 года), стал HighscreenPP5420[35]. С выходом Android третьей версии (Honeycomb), ориентированной на планшеты[36], всё больше производителей стали объявлять и о выпуске планшетов на этой платформе[37]. Также компания Google в сотрудничестве с разными гигантами мобильной индустрии выпускает собственные устройства в серии «Google Nexus». Именно эти устройства первыми получают обновления до новых версий.

Кроме смартфонов и планшетов, операционную систему Android устанавливают и на другие устройства. Так, в конце 2009 года появилась в продаже первая фоторамка, работающая на Android[38][39]. В июне 2011 года итальянская компания Blue Sky анонсировала выпуск интеллектуальных наручных часов i’m Watch под управлением ОС Android[40]. В августе 2012 года Nikon представила первую в мире фотокамеру, которая также работает на Android[41]. В серии «Google Nexus» присутствуют не только смартфоны и планшеты, но и медиаплеер Nexus Q, работающий на Android[42] и Nexus Player.

Кроме того, энтузиасты портировали Android на ряд известных устройств, среди которых, например, смартфоны на платформеWindows Mobile HTC Touch Dual и HTC TyTN II, на которых Android был запущен в режиме эмуляции[43]. Также было осуществлено полноценное портирование на такие устройства, как интернет-планшеты, работающие на Maemo — Nokia N810[44] и Nokia N900(порт под названием Nitdroid)[45][46], на смартфоны Nokia N9[47], работающий на платформе MeeGo, и HTC HD2, работающий на операционной системе Windows Mobile, на котором ОС Android можно запускать как с microSD-карты, так и с внутренней NAND-памяти. При этом установленная система имеет полную, ничем особо не ограниченную функциональность. Помимо этого, есть удачный опыт установки Android на некоторые устройства Apple — iPhone, iPod Touch и iPad[48] с помощью специальной программы под названием Openiboot, которая предназначена для запуска на данных устройствах разнообразных ОС, в том числе и Android. Вышли прошивки с ограниченной функциональностью на устройствах на операционной системе Bada. Компания Koolu не только занялась портированием Android на Neo FreeRunner, но и строила свой бизнес на продаже этих смартфонов с предустановленной мобильной платформой от Google. Первый официальный и общедоступный бета-релиз порта Android на Neo FreeRunner от Koolu состоялся в декабре 2008 года[49]. Также Android портирован на архитектуру x86[50].

В октябре 2012 года исполнительный директор компании Ларри Пейдж сообщил, что было активировано уже более 500 миллионов смартфонов и планшетов на базе Android, а также заявил, что ежедневно активируется 1,3 миллиона устройств на базе этой операционной системы[51].

В начале сентября 2013 года было объявлено о том, что в мире уже активировано свыше миллиарда устройств на Android[52].

29 сентября 2015 года СЕО Google Сундар Пичаи отметил, что число пользователей устройств на базе Android превысило 1.4 млрд

Программное обеспечение[править | править вики-текст]

Приложения под операционную систему Android являются программами в нестандартном байт-коде для виртуальной машины Dalvik, для них был разработан формат установочных пакетов .APK. Для работы над приложениями доступно множество библиотек: Bionic (библиотека стандартных функций, несовместимая с glibc); мультимедийные библиотеки на базе PacketVideo OpenCORE (поддерживают такие форматы, как MPEG-4, H.264, MP3, AAC, AMR, JPEG и PNG); SGL (движокдвухмерной графики); OpenGL ES 1.0 ES 2.0 (движок трёхмерной графики); Surface Manager (обеспечивает для приложений доступ к 2D/3D); WebKit (готовый движок для веб-браузера; обрабатывает HTML, JavaScript); FreeType (движок обработки шрифтов); SQLite (легковесная СУБД, доступная для всех приложений); SSL (протокол, обеспечивающий безопасную передачу данных по сети). По сравнению с обычными приложениями Linux приложения Android подчиняются дополнительным правилам[53]: Content Providers — обмен данными между приложениями; Resource Manager — доступ к таким ресурсам, как файлы XML, PNG, JPEG; Notification Manager — доступ к строке состояния; Activity Manager — управление активными приложениями.

Google предлагает для свободного скачивания инструментарий для разработки (Software Development Kit), который предназначен для x86-машин под операционными системами Linux, Mac OS X (10.4.8 или выше), Windows XP, Windows Vista и Windows 7. Для разработки требуется JDK 5 или более новый.

Разработку приложений для Android можно вести на языке Java (не ниже Java 1.5). Существует плагин для Eclipse — Android Development Tools (ADT), предназначенный для Eclipse версий 3.3—3.7. Также существует плагин для IntelliJ IDEA, облегчающий разработку Android-приложений[54], и для среды разработкиNetBeans IDE[55], который, начиная с версии NetBeans 7.0, перестал быть экспериментальным, хоть пока и не является официальным. Кроме того, существует Motodev Studio for Android — комплексная среда разработки на базе Eclipse, позволяющая работать непосредственно с Google SDK.

В 2009 году в дополнение к ADT был опубликован Android Native Development Kit (NDK)[56] — пакет инструментариев и библиотек, позволяющий реализовать часть приложения на языке С/С++. NDK рекомендуется использовать для разработки участков кода, критичных к скорости.

В 2013 году Google представила новую среду разработки Android Studio, основанную на IntelliJ IDEA от JetBrains.

Android L Developer Preview.

В 2013-м году состоялся релиз Embarcadero RAD Studio — XE5. Возможность разработки нативных приложений для платформы Android. Процесс создания Android приложения не требует дополнительных устройств, кроме, собственно, Android устройства (в принципе, можно обойтись и эмулятором).

В Android 4.4 появилась возможность сменить виртуальную машину Dalvik на ART (Android Runtime). ART отличается повышенной скоростью загрузки приложения. Проработан механизм оптимизации памяти.

В Android 5 перерисован дизайн, базирующийся на концепции Material Design, добавлен режим энергосбережения Project Volta, выбор машины пропал, вместо Dalvik стала использоваться ART.

В Android 6 появился интеллектуальный режим расхода энергии Doze и запрет выхода в интернет и работы в фоне давно не используемых приложений App Standby.

Android Developer Challenge[править | править вики-текст]

Для стимулирования разработчиков в ноябре 2007 года компания Google объявила конкурс Android Developer Challenge с призовым фондом в 5 млн долларов[8][57]. Участникам конкурса предлагалось создать любое приложение из самых разных областей — социальные сети, работа с информацией различного типа, игры и т. д.[58]Мероприятия конкурса ADC проходили в 2008 году и закончились награждением 50 финалистов крупными денежными призами (25—275 тыс. долларов)[59].

27 мая 2009 года был объявлен новый конкурс ADC2 с призовым фондом в 2 млн долл. (главный приз — 250 тыс. долл.)[60]. Подача приложений на конкурс продолжалась с 24 по 31 августа 2009 года. С 24 сентября по 6 октября в рамках первого раунда ADC2 пользователи путём голосования отбирали приложения для участия во втором раунде. 5 ноября был опубликован список из 200 лучших приложений (по 20 приложений в каждой из 10 категорий), попавших во второй раунд, и началось голосование пользователей за эти приложения. 24 ноября голосование во втором раунде было закрыто, начал работу специальный комитет судей-экспертов, которые с учётом мнения пользователей отбирали лучшие приложения. 30 ноября был опубликован список победителей конкурса[61].

Магазин приложений «Google Play»[править | править вики-текст]

22 октября 2008 года Google объявила об открытии онлайн-магазина приложений для ОС Android — Android Market. По соглашению, разработчики получают 70 % прибыли, операторы сотовой связи — 30 %[62]. В феврале 2009 года для разработчиков из США и Великобритании появилась возможность брать плату за свои приложения в Android Market[63]. Компания Sony Ericsson первая запустила собственный канал в онлайн-магазине приложений Android Market. В нём представлены приложения и игры, которые рекомендованы компанией[64].

На декабрь 2011 года с момента создания Android Market было скачано 10 млрд приложений[65][66].

В марте 2012 года компания Google объединила мультимедийные сервисы «Книги», «Android Market», «Музыка» и другие в единый сервис Google Play[67]. Интернет-магазин Google Play работает в 190 странах[68] и насчитывает более 700 тысяч приложений, а за время работы сервиса набралось около 25 млрд скачиваний[69].

Исходный код[править | править вики-текст]

22 октября 2008 года альянс OHA опубликовал исходный код платформы Android на открытом исходном коде Android: и операционная система, и промежуточное ПО (middleware), и основные конечные приложения, написанные на Java[70]. Общий объём исходного кода Android составил 2,1 ГБ. «Предпочтительной лицензией» на исходный код Android является лицензия Apache 2.0[1]. После выпуска Android 3.0 «Honeycomb» президент мобильного подразделения Google Энди Рубин (англ.) заявил о том, что открытие исходного кода новой версии системы будет отложено по причине того, что система была плохо готова для запуска на коммуникаторах и требует значительных оптимизаций[71]. Это решение вызвало критические оценки аналитиков: например, обозреватель ZDNet Кристофер Доусон назвал такой ход Google разочаровывающим[72]. Но, согласно данным компанией обещаниям, Google открыла осенью 2011 года исходные коды следующей версии системы — Android 4.0 Ice Cream Sandwich[73].

Заявления о нарушении прав[править | править вики-текст]

Oracle Corporation обвинила Google в нарушении прав интеллектуальной собственности на Java и направила соответствующий иск в суд[74][75][76]. Подобные претензии к компании Google предъявили юристы компании Brown Rudnick LLP, обвинив разработчиков в том, что они нарушают лицензию GPL2 своей библиотекой Bionic[77]. Данное заявление вызвало неоднозначную реакцию в прессе[78][79][80], при этом ряд экспертов пришли к предварительному выводу, что обвинения, возможно, преждевременны[81].

31 мая 2012 года судья Уильям Алсуп (William Alsup) вынес решение по поводу правомерности претензий Oracle на обладание авторскими правами на 37 API, которые использует Google в платформе Android и которые дают возможность разработчикам создавать совместимые с Java коды. Согласно вердикту Алсупа, интерфейсы API, которые являются предметом рассмотрения в споре Oracle — Google, не могут быть объектом защиты авторского права: «Поскольку специфический код, используемый при реализации методики, различается, каждый в соответствии с законом об охране авторских прав может написать свой собственный код для выполнения точно такой же функции или спецификаций, или же других методов, используемых в Java API. Не имеет значения, что декларации или заглавные строки методики являются идентичными. Когда существует лишь один путь для воплощения идеи или функции, каждый волен делать это, и никто не вправе монополизировать данный способ воплощения»[82]. Впрочем, после апелляции в вышестоящей инстанции корпорации Oracle удалось добиться отмены трактовок судьи Алсупа касательно защиты интерфейсов программирования авторским правом, и дело вернулось на пересмотр с учётом вердикта Апелляционного суда[83].

Альтернативные прошивки[править | править вики-текст]

Существует сообщество энтузиастов, разрабатывающее открытые варианты прошивок Android — CyanogenMod, MIUI, AOKP (Android Open Kang Project), AOSP, Paranoid Android и другие. Модифицированные версии Android создаются для дополнения операционной системы новыми настройками, опциями, функциями или для улучшения качества работы устройств[84]; удаления из Android-устройства сервисов Google для исключения возможности передачи идентификационной информации на серверы компании, например, информацию о перемещении пользователя в реальном времени, что привело к судебному разбирательству[85]; более оперативного и частого (по сравнению с производителями самих аппаратов) предоставления новых версий Android[86]. При технической или программной неисправности устройства, вызванной неправильным использованием root-доступа, в гарантийном ремонте устройства сервисный центр может отказать[87].

Достоинства[править | править вики-текст]

Некоторые обозреватели отмечают, что Android проявляет себя лучше одного из своих конкурентов, Apple iOS, в ряде особенностей, таких как веб-сёрфинг, интеграция с сервисами Google и прочих[88]. Также Android, в отличие от iOS, является открытой платформой, что позволяет реализовать на ней больше функций.

  • Несмотря на изначальный запрет на установку программ из «непроверенных источников» (например, с карты памяти), это ограничение отключается штатными средствами в настройках аппарата, что позволяет устанавливать программы на телефоны и планшеты без интернет-подключения (например, пользователям, не имеющим Wi-Fi-точки доступа и не желающим тратить деньги на мобильный интернет, который обычно стоит дорого), а также позволяет всем желающим бесплатно писать приложения для Android и тестировать на своём аппарате. Кроме того, возможность установки программ из «непроверенных источников» способствует пиратству на платформе Android.
  • Android доступен для различных аппаратных платформ, таких как ARM, MIPS, x86.
  • Существуют альтернативные Google Play магазины приложений: Amazon Appstore (англ.), Opera Mobile Store, Yandex.Store, GetUpps!,Mobogenie, F-Droid (англ.), 1Mobile Market.
  • В версии 4.3 введена поддержка многопользовательского режима[89].

Критика[править | править вики-текст]

  • Наличие в некоторых Android-устройствах сервисов Google, обеспечивающих возможность передачи идентификационной информации на серверы компании, например, информацию о перемещении пользователя в реальном времени.
  • В версии Android 1.6 разработчики добавили Native Development Kit[90], который позволяет писать собственные низкоуровневые модули для системы на языках C/С++, опираясь на стандартные Linux-библиотеки. Хотя, например, стандартная библиотека языка Си на платформе Android, известная как Bionic, как раз не является стандартной и полностью совместимой с libc.
  • Для доступа к Google Play и другим сервисам от Google необходимо использовать проприетарные приложения, которые производитель телефона имеет право устанавливать на телефон только после заключения контракта с Google[91].
  • Конкуренты Android выступили с критикой платформы, обвиняя её в чрезмерной фрагментации, создающей препятствия разработчикам[92][93]. Google опровергла все обвинения, заявив, что никаких подобных проблем нет[94].
  • Подверглось критике решение Google не размещать в широком доступе код Android 3.0 Honeycomb, доступный только для участников Open Handset Alliance или по индивидуальному запросу после подписания соглашения. Google мотивирует это неготовностью платформы и мерой предупреждения небрежной её реализации[95]. Ричард Столлман заявлял, что «всё просто и ясно: за исключением ядра Linux, Android 3 представляет собой несвободный софт» и «несмотря на то, что телефоны с Android на сегодняшний день не так плохи, как смартфоны Apple или Windows, нельзя сказать, что они уважают вашу свободу»[96]. В настоящий момент Google открыл исходный код для всех версий Android вплоть до 6.0[97], а также отправил в Linux все изменения, в соответствии с GPL[98].
  • По данным Lookout Security Mobile, за 2011 год у пользователей Android-смартфонов было украдено около миллиона долларов США (напр., отправка СМС без ведома владельца телефона)[99]. Однако это зачастую возникает у пользователей, которые невнимательно читают списки разрешений при установке какого-либо приложения.
  • Из-за использования Java-кода в виртуальной машине вместо нативного машинного кода, нередко отмечается снижение производительности и увеличение энергопотребления устройств с ОС Android[источник?].

Награды и достижения[править | править вики-текст]

Издание PC Magazine присвоило операционной системе Android 4.0 Ice Cream Sandwich награду «Выбор редакции», отметив, что новая версия ОС принесла платформе множество улучшений, в том числе устранив различия между смартфонной и планшетной системами[100].

В марте 2012 года газета «Ведомости» сообщила, что Android смог выиграть российский рынок планшетных компьютеров у своего главного конкурента — Apple. Причиной тому аналитики назвали то, что Apple задерживает премьеры своих устройств на несколько месяцев. Одновременно с этим покупателям предлагались их «андроидные» аналоги по более низкой цене[101].

Android 4.0 Ice Cream Sandwich получила «золото» за лучшую платформу на 2012 User Experience Awards[102].

Интересные факты[править | править вики-текст]

  • Кодовое имя каждой версии операционной системы Android, начиная с версии 1.5, представляет собой название какого-либо десерта. Первые буквы наименований в порядке версий соответствуют буквам латинского алфавита: 1.5 Cupcake («кекс»), 1.6 Donut («пончик»), 2.0/2.1 Eclair («эклер»), 2.2 Froyo (коммерч. обозначениедесерта «замороженный йогурт[en]» — от англ. frozen yogurt), 2.3 Gingerbread («имбирный пряник»), 3.0 Honeycomb («пчелиные соты»), 4.0 Ice Cream Sandwich («мороженое в вафлях[en]», в виде брикета), 4.1/4.2/4.3 Jelly Bean («желейные бобы[en]» — вид конфет), 4.4 KitKat (в честь одноимённого бренда шоколадных батончиков[103]), 5.0/5.1 Lollipop («леденец на палочке»), 6.0 Marshmallow («маршмэллоу»).
  • Специально для платформы Android были созданы семейства шрифтов Droid и Roboto.
  • По данным на февраль 2011 года, устройства с ОС Android уверенно лидировали в списке самых популярных смартфонов Великобритании, оставив позади iPhone 4c iOS[104]. По прогнозам экспертов, это первый шаг ОС Android к глобальному лидерству на рынке мобильных операционных систем.
  • Компания Microsoft, продвигающая альтернативную ОС Windows Phone, получает лицензионные отчисления от производителей техники и ПО для Android. При этом доход компании Microsoft, получаемый таким образом, более чем в 2 раза выше, чем доход компании-разработчика (Google)[105].
  • В версиях Android 2.3 и выше есть пасхальное яйцо. Чтобы его запустить, нужно зайти в «Настройки», потом зайти в «Об устройстве», найти функцию «Версия Android», и быстро нажимать на неё несколько раз (обычно 3). На экране в версии 2.3 появится рисунок[ком. 2]; 4.0 — один Android, который увеличивается, а затем появляется много летающих; 4.1, 4.2 и 4.3 — летающие конфеты; в 4.4 — вращающаяся буква «K», затем надпись «Android» в стиле батончика KitKat, затем — появляются плитки в стиле Windows с логотипами предыдущих версий Android; в 5.0 и 5.1 сначала появляется леденец с надписью «Lollipop» (в версии 6.0 появляется Маршмэллоу), затем откроется мини-игра в стиле «Flappy Bird».
  • В версиях Android 4.2 и выше по умолчанию отключены инструменты разработчика, для включения нужно семь раз нажать на номер сборки.

Примечания[править | править вики-текст]

Комментарии
  1. «Андроид» не является официальным названием торговой марки в России.
  2. Не все телефоны поддерживают данную функцию (например, модели компании Samsung: gt-i9001).
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Литература[править | править вики-текст]

  • Голощапов А. Google Android: программирование для мобильных устройств. — СПб.: БХВ-Петербург, 2010. — 448 с. — ISBN 978-5-9775-0562-8.
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  • Сатия Коматинени, Дэйв Маклин. Android 4 для профессионалов. Создание приложений для планшетных компьютеров и смартфонов = Pro Android 4. — М.:Вильямс. — 880 с. — ISBN 978-5-8459-1801-7.
  • Роджерс Р., Ломбардо Д. Android. Разработка приложений. — М.: ЭКОМ Паблишерз, 2010. — 400 с. — ISBN 978-5-9790-0113-5.
  • Донн Фелкер. Android: разработка приложений для чайников = Android Application Development For Dummies. — М.: Диалектика, 2011. — 336 с. — ISBN 978-5-8459-1748-5.

Android(Azerbaycanca)

Androidsmartfonlar, planşetlər, kompüterlər, Elektron kitablar, Televizorlar, Google Glass [2]və digər cihazlar üçün nəzərdə tutulmuş, Linux nüvəli [3] açıq qaynaq kodlu əməliyyat sistemidir.Gələcəkdə avtomobillərin[4] də dəstəklənməsi planlaşırılır.Əvvəcə Android İnc. Şirkəti tərəfindən inkişaf etdirilib,daha sonralar Google tərəfindən alınmışdır.Google-un bu təşəbbüsü Open Handset Alliance-nın yaranmasına səbəb olmuşdur, hansı ki hal-hazırda platformanın sonrakı inkişafıyla məşğuldur. Android, cihazların funkionallığını artıran proqramlar yazan böyük bir mühəndis(developper) qrupuna sahibdir.Android üçün hal-hazırda 1 milyondan çox proqram vardır.Android əməliyyat sitemi ilə işləyən proqramlar müxtəlif saytlardan yüklənə bilməsiylə yanaşı, Google tərəfindən qurulan Google Play mağazasından da də yüklənə bilir. 2014-cü ilin ikinci yarısında satılan smartfonların 86%-i android[5] əməliyyat sistemi ilə təchiz olunmuşdur.2014-cil boyunca 1 milyarddan çox android cihaz satılmışdır. [6

Tarixi[redaktə | əsas redaktə]

2005-ci ilin iyulunda Google korporasiyası Android Inc[7] şirkətini aldı. 5 noyabr 2007-ci il şirkət rəsmən Open Handset Alliance(OHA) yaradılmasını və Android açıq mobil platformasını elan etdi[8]. 12 noyabr 2007-ci ildə isə İttifaq paketin birinci versiyası olan Android “Early Look” SDK və Android emulyatorunu təqdim etdi[7][9].

23 sentyabr 2008-ci il rəsmən əməliyyat sisteminin birinci versiyası və həmçinin ilk tam mühəndis paketi SDK 1.0 çıxdı[10][11].Platformanın birinci versiyasının çıxış anından etibarən sistemin bir neçə yeniləməsi oldu. Bu yeniləmələr, bir qayda olaraq, aşkar edilmiş səhvlərin düzəldilməsi və sistemə yeni funksionallığın əlavə edilməsi ilə əlaqədar idi.

2009-cu ildə platforma üçün 4 tam yeniləmə(update) təqdim olundu.Nəhayət fevral ayında müxtəlif səhvlərin aradan qaldırılması üçün 1.1 versiya versiya çıxdı[12].Aprel[13] və sentyabr[14] aylarında isə daha iki yeniləmə 1.5 «Cupcake»və 1.6 «Donut» təqdim edildi. «Cupcake» yeniləməsi əhəmiyyətli dəyişiklikləri əlavə etdi.Bunlar – virtual klaviatura,videoların oynadılması və qeydə alınması,brauzer və s. idi[15].«Donut»da isə ilk dəfə olaraq müxtəlif ölçülü və müxtəlif sıxlııqlı ekranların və CDMA[12] şəbəkələrinin dəstəklənməsi mümkün oldu.Həmin ilin oktyabr ayında Android 2.0 «Eclair»[16] versiyası təqdim olundu.Bu versiya bir neçə Google hesabının dəstəklənməsi, HTML5 brauzerin dəstəklənməsi və həmçinin bir neçə yenilənmədən sonra canlı divar kağızlarının istifadəsi ilə əlamətdar oldu.

2010-cu ilin [17] ortalarında Google, Android 2.2 versiyasını «Froyo», 2010-cu ilin sonlarında [18] Android 2.3 versiyasını «Gingerbread» adları altında təqdim etdi. «Froyo» yeniləməsindən sonra smartfonu giriş nöqtəsi(acces point) kimi istifadə etmək,ekran kilidinin şifrəsini həm rəqəm həm də hərf-rəqəm kombinasiyaları ilə şifrələmək mümkün oldu. «Gingerbread» yeniləməsi isə kopyalama və yapışdırma funksiyası üzərində tam nəzarət, cihazda bir-neçə kameranın dəstəklənməsi və s. digər yenilikləri özü ilə gətirdi. [12]

22 fevral 2011-ci ildə [19] Planşetlər üçün uyğunlaşdırılmış Android 3.0 «Honeycomb»[20] rəsmən təqdim edildi.

Android 4.0 «Ice Cream Sandwich» 19 oktyabr 2011ci ildə [21] çıxan ilk universal platforma idi hansı ki həm planşetlər üçün həm də smartfonlar [22][23] üçün nəzərdə tutulmuşdu.Həmçinin bu versiya özü ilə yeni «Holo» interfeysini gətirmişdi .

2012-ci il iyun ayında yeni versiya olan Android 4.1 «Jelly Bean» təqdim olundu [24].Bu versiyaya həmin ilin oktyabr ayında [25] 4.2 və 2013-cü ilin iyul ayında [26] 4.3 yeniləmələri gəldi.

31 oktyabr 2013-cü ildə Google, əməliyyat sisteminin növbəti versiyası olan Android 4.4 təqdim etdi hansı ki,adını Nestle[27] kompaniyası ilə olan müqailəyə əsasən «KitKat» şokoladından götürmüşdü.İlk olaraq Kitkat Nexus 5 cihazlarında görülmüşdür.

Android L Developer Preview

25 iyun 2014-cü ildə Google Android Lollipop-u mühəndislər üçün elan etdi [28].

2014-cü ildə geyiləbilən cihazlar üçün Android Wear əməliyyat sistemi təqdim olunmuşdur.Həmçinin maşınlar üçün Android Auto və televizorlar üçün Android TV təqdim olunmuşdur.Bununla da Android yalnız mobil cihazlar üçün əməliyyat sistemi olmadığını sübut etmişdir.

15 oktyabr 2014-cü ildə rəsmi şəkildə Android 5.0 Lollipop versiyası təqdim olundu.Sistemin əsas yeniliyi yeni Material Design inerfeysi oldu.

Android versiyalari.png

Tətbiqi[redaktə | əsas redaktə]

HTC Dream (T-Mobile G1) – Android ƏS ilə işləyən ilk smartfon

Android 1.5-in emulyatorda ekran görüntüsü

Androidlə işləyən ilk qurğu 23 sentyabr 2008-ci ildə nümayiş olunmuş HTC Dream smartfonu olmuşdur.Tezliklə digər smartfon istehsalçıları da Android siteminə keçəcəklərini bəyan etdi.Androidin 3-cü versiyası olan planşetlər üçün uyğunlaşdırılmış [29] «Honeycomb»un çıxışından sonra Android sisteminə keçən smartfon istehsalçılarının sayı daha da artdı[30].Bundan başqa mobil sənayenin müxtəlif nəhəngləri ilə əməkdaşlıq edən Google şirkəti öz «Google Nexus» seriyasında şəxsi qurğularını istehsal edir.Məhz bu qurğular Android üçün olan yeniləmələri birinci alır.Google Nexus seriyasında nəinki yalnız smartfon və planşetlər həmçinin Android sistemi ilə işləyən Nexus Qmediaplayer də var. Smartfonlar və planşetlərdən başqa android əməliyyat sistemi digər qurğularda da istifadə olunnur.2011ci ilin iyun ayında italyan şirkəti Blue Sky android əməliyyat sistemi ilə işləyən intelektual qol saatı I’m Watch[31]-ı təqdim etdi.2012ci ilin avqustunda Nikon şirkəti dünyada ilk olaraq Android sistemi ilə işləyən fotoaparatını təqdim etdi[32]. Bundan başqa Android həvəskarları digər məhşur qurğulara da Android sistemini tətbiq etməyi (port etmək)başarmışlar.Məsələn, Windows Mobile platformasında olan HTC Touch DualHTC TyTN II smartfonları emulyator rejimində Android əməliyyat sistemində işləyə bilir[33].Həmçinin Maemo platformasıyla işləyən Nokia N810[34] planşeti, Nokia N900 [35][36], Meego platformasında işləyən Nokia N9[37]Windows Mobile platformasında işləyən HTC HD2smartfonlarına tamamilə android əməliyyat sitemi tətbiq olunmuşdur.Androidi bu qurğularda həm microSD kartdan həm də daxili NAND yaddaşdan çalışdırmaq olar.Bu cür Android digər androidlərdən heç bir cəhətinə görə fərqlənmr.Bundan basqa iphone,İpod touch,İpad kimi apple cihazlarına da android sisteminin təbiqi təcrübəsi mövcuddur[38]. 2012-ci ilin oktyabrında Google-un icraçı direktoru Larri Peyc artıq 500 milyondan çox smartfonun Android sistemində aktivləşdirildiyini və həmçinin bu sayın hər gün 1.3 milyon daha artdığını bildirdi[39]. 2013-cü il sentyabrın əvvlində isə artıq dünyada 1 milyarddan çox android cihazın aktivləşdirildiyi elan olundu[40].

Google Play Mağazası[redaktə | əsas redaktə]

22 oktyabr 2008ci ildə Google şirkəti Android ƏS üçün “ Android Market” adlı onlayn mağazanın açılışını elan etdi.Razılaşmaya əsasən istehsalçılar gəlirin 70%ni mobil operatorlar isə 30%ni alırlar [41].2009-cu ilin fevralında ABŞ-danBöyük Britaniyadan olan istehsalçilar üçün mağazaya ödənişli proqramların qoyulması aktiv oldu [42].İlk dəfə olaraq Sony Ericson şirkəti Android Market onlayn mağazasında kanal açaraq öz oyunlarını,proqramlarını nümayiş etdirmişdir [43]. Yaradıldığı 2011 dekabr ayından etibarən Android Marketdən 10 milyarddan çox proqram yüklənilib[44][45]. 2012ci ilin mart ayında Google «Google Books», Android Market, Google Music və digər servislərin vahid bir servisdə – Google Playdə birləşdirdi[46].Google Play internet mağazası 190 ölkədə faliyyət göstərir[47] və 700 mindən çox proqramdan ibarətdir.Yarandığı gündən bu günə kimi mağazadan 25 milyard yükləmə edilmişdir[48].

Modifikasiya və Root[redaktə | əsas redaktə]

Bəzi həvəskar cəmiyyətlər vardır ki bunlar Androidin modifikasıyası ilə məşğul olurlar.Bu modifikasiyalara CyanogenMod, MIUI, AOKP (Android Open Kang Project)və s-ni göstərmək olr.Modifikasiya Androidə yeni funksiyalar,seçimlər,tənzimləmələr əlavə etmək üçün edilir[49]. Modifikasiya olunmuş Android yükləmək üçün smartfon Root (Superuser) səlahiyyətlərinə malik olmalıdır.Qeyd etmək lazımdır ki düzgün şəkildə yerinə yetirilməyən root əməliyyatı bir çox problemlərə, həmçinin qurğunun zəmanətinin itirilməsinə səbəb ola bilər [50].

Maraqlı Faktlar[redaktə | əsas redaktə]

  • Android əməliyyat sisteminin hər versiyasının kod adı, 1.5 versiyasından başlayaraq, hər hansı bir desertin adı ilə adlandırılmışdır.Hər bir adın ilk hərfi latın əlifbasının hərflərinə uyğun seçilmişdir: 1.5 Cupcake («keks»), 1.6 Donut («ponçik»), 2.0/2.1 Eclair («Ekler pirojnası»), 2.2 Froyo («dondurulmuş yoqurt»), 2.3 Gingerbread («xəncəfilli peçenye»), 3.0 Honeycomb («arı pətəyi»), 4.0 Ice Cream Sandwich , 4.1, 4.2, 4.3 Jelly Bean («jele konfeti”), 4.4 KitKat (şokolad batonlarının[51] eyni adlı markasının şərəfinə) və 5.0 Lollipop («çubuqlu nabat»).
  • Xüsusi olaraq Android platforması üçün DroidRoboto şiriftləri yaradılmışdır.
  • Androidin rəsmi saytında hələ də cihazlar üçün minimal sistem tələbləri göstərilməmişdir.
  • 2011-ci ilin fevral ayının məlumatlarına görə Android ƏS ilə işləyən qurğular iPhone 4 [52] -ü arxada qoyaraq Böyük Britaniyanın ən məşhur smartfonlarının siyahısında əminliklə liderlik etmişdir.
  • Android 2.3 və yuxarı versiyalarda Pasxa yumurtası gizlədilmişdir.Onu işə salmaq üçün «Settings»dən «About Phone»yə daxil olub « Android version» yazısının üzərinə 3 dəfə basmaq lazımdır.Hər bir versiyada qarşınıza ya xüsusi bir şəkil və ya animasiya çıxacaq.
  • Android 4.2 və daha yuxarı versiyalarda «Developer options» (mühəndis modu) söndürülmüşdür.Onu aktiv etmək üçün «Build number » yazısına 7 dəfə basmaq lazımdır.

İstinad[redaktə | əsas redaktə]

  1. Jump up “Licenses”. Android Open Source Project. Android. Arxivləşdirilib: [1] saytından 2013-01-21 tarixində. İstifadə tarixi: 2013-01-19.
  2. Jump up “Larry Page Says Google Glass Runs On Android”. 2013-04-18. Arxivləşdirilib: [2] saytından 2013-04-28 tarixində. İstifadə tarixi: 2013-04-20.
  3. Jump up “What is Android?”. Android Developers. Arxivləşdirilib: [3] saytından 2012-03-01 tarixində. İstifadə tarixi: 2010-03-06.
  4. Jump up “Android auto”.
  5. Jump up “Android Captures Record 85% Share of Global Smartphone Shipments in Q2 2014”. http://www.strategyanalytics.com.+2014-07-30. İstifadə tarixi: 2014-08-03.
  6. Jump up Алексей Орлов. “Продажи Android-смартфонов в 2014 году побили все рекорды”.
  7. Jump up to:7,0 7,1 “Google Android — первые шаги”. 3DNews. İstifadə tarixi: 2012-09-19.
  8. Jump up “Industry Leaders Announce Open Platform for Mobile Devices”. Open Handset Alliance. Arxivləşdirilib: [4] saytından 2013-01-21 tarixində. İstifadə tarixi: 2012-09-19.
  9. Jump up “Open Handset Alliance Releases Android SDK”. Open Handset Alliance. Arxivləşdirilib: [5] saytından 2013-01-21 tarixində. İstifadə tarixi: 2012-09-19.
  10. Jump up “Этот день в истории бизнеса: «Яндекс», первая в мире жвачка и Android”. Forbes. Arxivləşdirilib: [6] saytından 2013-01-21 tarixində. İstifadə tarixi: 2012-09-19.
  11. Jump up Morrill, Dan (2008-09-23). “Announcing the Android 1.0 SDK, release 1”. Android Developers Blog. Arxivləşdirilib: [7] saytından 2012-07-07 tarixində. İstifadə tarixi: 2011-08-19.
  12. Jump up to:12,0 12,1 12,2 “Android: A visual history”. The Verge. Arxivləşdirilib: [8] saytından 2013-01-21 tarixində. İstifadə tarixi: 2012-09-19.
  13. Jump up Ducrohet, Xavier (2009-04-27). “Android 1.5 is here!”. Android Developers Blog. Arxivləşdirilib: [9] saytından 2012-07-07 tarixində. İstifadə tarixi: 2011-08-19.
  14. Jump up Ducrohet, Xavier (2009-09-15). “Android 1.6 SDK is here”. Android Developers Blog. Arxivləşdirilib: [10] saytından 2012-07-07 tarixində. İstifadə tarixi: 2011-08-19.
  15. Jump up “Android 1.5 Platform Highlights”. Android Developers. Arxivləşdirilib: [11] saytından 2013-01-21 tarixində. İstifadə tarixi: 2012-06-19.
  16. Jump up “Android 2.0 Platform Officially Unveiled”. MacRumors.com. Arxivləşdirilib: [12] saytından 2013-01-21 tarixində. İstifadə tarixi: 2013-01-18.
  17. Jump up Ducrohet, Xavier (20 May 2010). “Android 2.2 and developers goodies”. Android Developers Blog. Arxivləşdirilib: [13] saytından 2012-07-07 tarixində. İstifadə tarixi: 2010-05-20.
  18. Jump up Ducrohet, Xavier (6 December 2010). “Android 2.3 Platform and Updated SDK Tools”. Android Developers Blog. Google. Arxivləşdirilib: [14] saytından 2012-07-07 tarixində. İstifadə tarixi: 2010-12-07.
  19. Jump up “Final Android 3.0 Platform and Updated SDK Tools”. Android Developers Blog. Arxivləşdirilib: [15] saytından 2013-01-21 tarixində. İstifadə tarixi: 2012-09-19.
  20. Jump up “Предварительный обзор ОС Android 3.0 Honeycomb: горшочек меда для планшетов”. Mobi. Arxivləşdirilib: [16] saytından 2013-01-21 tarixində. İstifadə tarixi: 2012-09-19.
  21. Jump up Nancy Gohring (2011-10-19). “Samsung, Google Unveil Latest Android OS, Phone”. PCWorld. Arxivləşdirilib: [17] saytından 2012-07-07 tarixində. İstifadə tarixi: 2011-10-19.
  22. Jump up “Универсальный робот. Обзор платформы Android 4.0”. Россия-24. Arxivləşdirilib: [18] saytından 2013-01-21 tarixində. İstifadə tarixi: 2012-09-19.
  23. Jump up “Что нового в Android 4.0 Ice Cream Sandwich”. Компьютерра. İstifadə tarixi: 2012-09-19.
  24. Jump up “Android 4.1 Jelly Bean и другие новости с Google I/O 2012”. Mobile-review.com. Arxivləşdirilib: [19] saytından 2013-01-21 tarixində. İstifadə tarixi: 2012-09-19.
  25. Jump up “Google представила Android 4.2 Jelly Bean”. Ferra.Ru. Arxivləşdirilib: [20] saytından 2012-12-02 tarixində. İstifadə tarixi: 2012-11-21.
  26. Jump up “Google представила новый Nexus 7, Android 4.3 и Chromecast”. Mail.ru. Arxivləşdirilib: [21] saytından 2013-07-27 tarixində. İstifadə tarixi: 2013-07-26.
  27. Jump up “Новая версия Android — 4.4 KitKat”. Mail.Ru. İstifadə tarixi: 2013-11-02.
  28. Jump up “Превью платформы Android L станет доступно разработчикам в среду.”. lenta.ru. İstifadə tarixi: 26.6.2014.
  29. Jump up “Обзор планшета Samsung Galaxy Tab 10.1 на базе ОС Android 3.1”. iXBT.com. Arxivləşdirilib: [22] saytından 2012-10-23 tarixində. İstifadə tarixi: 2012-09-17.
  30. Jump up “Планшетный бум ждите весной”. Slon.ru. Arxivləşdirilib: [23] saytından 2012-10-23 tarixində. İstifadə tarixi: 2012-09-17.
  31. Jump up “i’m WATCH — многофункциональные наручные часы, работающие на Android”. Mobile-review.com. Arxivləşdirilib: [24] saytından 2012-10-23 tarixində. İstifadə tarixi: 2012-09-17.
  32. Jump up “Nikon Coolpix S800c — первая настоящая фотокамера на Android”. 3DNews. İstifadə tarixi: 2012-09-17.
  33. Jump up “HTC Dream: на конференцию Google заглянул андроид (видео, фото, ТТХ)”. Mobi. Arxivləşdirilib: [25] saytından 2012-10-23 tarixində. İstifadə tarixi: 2012-09-17.
  34. Jump up “Android 1.0 запущен на Nokia N810”. 3DNews. İstifadə tarixi: 2012-09-17.
  35. Jump up “Nokia N900 gets Android 2.3 Gingerbread port”. Androidcommunity.com. Arxivləşdirilib: [26] saytından 2012-10-23 tarixində. İstifadə tarixi: 2012-09-17.
  36. Jump up “Видео дня: Nokia N900 все лучше «притирается» к ОС Android”. 3DNews. İstifadə tarixi: 2012-09-17.
  37. Jump up Андрей Коробкин. (2012-07-22). “Платформу Android 4.1 Jelly Bean портировали на Nokia N9”. 3DNews. Arxivləşdirilib: [27] saytından 2012-07-23 tarixində. İstifadə tarixi: 2012-07-23.
  38. Jump up Кашарин Алексей. (2011-02-25). “Установка android на устройства iphone и ipad”. Arxivləşdirilib: [28] saytından 2012-03-01 tarixində.
  39. Jump up “Google: Количество активаций Android-устройств превысило 500 млн”. NEWSru.com. Arxivləşdirilib: [29] saytından 2013-01-21 tarixində. İstifadə tarixi: 2012-09-19.
  40. Jump up “Шоколадный батончик KitKat дал имя новой версии Android”. Lenta.ru. 2013-09-04. İstifadə tarixi: 2013-09-04.
  41. Jump up “Android Market: Now available for users”. Android Developers Blog. Arxivləşdirilib: [30] saytından 2013-08-19 tarixində.
  42. Jump up “Android Market update: support for priced applications”. Android Developers Blog. Arxivləşdirilib: [31] saytından 2013-08-19 tarixində.
  43. Jump up Компания Sony Ericsson открыла собственный канал в Android Market
  44. Jump up Android Market statistics from AndroLib, Androlib, Android Applications and Games directory
  45. Jump up “Android: 600 000 приложений, 1 млн активаций в сутки, 400 млн устройств”. Хабрахабр. Arxivləşdirilib: [32] saytından 2013-08-19 tarixində.
  46. Jump up Google переименовала Android Market в Google Play
  47. Jump up “Число приложений в интернет-магазине Google Play превысило 600 тысяч”. Digit.ru. Arxivləşdirilib: [33] saytından 2012-10-23 tarixində. İstifadə tarixi: 2012-09-19.
  48. Jump up “Пользователи Google Play совершили более 25 млрд загрузок за 4 года”. Digit.ru. Arxivləşdirilib: [34] saytından 2012-10-23 tarixində. İstifadə tarixi: 2012-09-26.
  49. Jump up “Проект AOKP выпустил альтернативные прошивки на базе Android 4.1”. 4PDA. Arxivləşdirilib: [35] saytından 2013-02-27 tarixində. İstifadə tarixi: 2013-02-21.
  50. Jump up “Root или не Root, вот в чем вопрос”. Хабрахабр. Arxivləşdirilib: [36] saytından 2013-02-27 tarixində. İstifadə tarixi: 2013-02-21.
  51. Jump up “Компания Google назвала новую версию Android в честь шоколадного батончика Kit Kat”.
  52. Jump up Kate Solomon. (2011-02-22). “iPhone 4 dips out of USwitch top five UK mobiles list”. TechRadar. Arxivləşdirilib: [37] saytından 2011-03-23 tarixində. İstifadə tarixi: 2011-03-21

Linux

Linux (pronounced Listeni/ˈlɪnəks/ lin-əks[9][10] or, less frequently, /ˈlnəks/ lyn-əks[10][11]) is a Unix-like and mostly POSIX-compliant[12]computer operating system (OS) assembled under the model of free and open-source software development and distribution. The defining component of Linux is the Linux kernel,[13] an operating system kernel first released on 5 October 1991 by Linus Torvalds.[14][15] The Free Software Foundation uses the name GNU/Linux to describe the operating system, which has led to somecontroversy.[16][17]

Linux was originally developed as a free operating system for personal computers based on the Intel x86 architecture, but has since been ported to more computer hardware platforms than any other operating system.[18] Because of its dominance on smartphones,Android, which is built on top of the Linux kernel, Linux has the largest installed base of all general-purpose operating systems.[19]Linux, in its original form, is also the leading operating system on servers and other big iron systems such as mainframe computersand virtually all fastest supercomputers,[20][21] but is used on only around 1.6% of desktop computers[22][23] with Linux-basedChrome OS taking about 5% of the overall and nearly 20% of the sub-$300 notebook sales.[24] Linux also runs on embedded systems, which are devices whose operating system is typically built into the firmware and is highly tailored to the system; this includes smartphones and tablet computers running Android and other Linux derivatives,[25] TiVo and similar DVR devices, network routers, facility automation controls, televisions,[26][27] video game consoles, and smartwatches.[28]

The development of Linux is one of the most prominent examples of free and open-source software collaboration. The underlyingsource code may be used, modified and distributed—​​commercially or non-commercially—​​by anyone under the terms of its respective licenses, such as the GNU General Public License. Typically, Linux is packaged in a form known as a Linux distribution, for both desktop and server use. Some of the popular mainstream Linux distributions are Debian, Ubuntu, Linux Mint, Fedora, openSUSE,Arch Linux and Gentoo, together with commercial Red Hat Enterprise Linux and SUSE Linux Enterprise Server distributions. Linux distributions include the Linux kernel, supporting utilities and libraries, and usually a large amount of application software to fulfill the distribution’s intended use.

Distributions oriented toward desktop use typically include a windowing system, such as X11, Mir or a Wayland implementation, and an accompanying desktop environment, such as GNOME or the KDE Software Compilation; some distributions may also include a less resource-intensive desktop, such as LXDE or Xfce. Distributions intended to run on servers may omit all graphical environments from the standard install, and instead include other software to set up and operate a solution stack such as LAMP. Because Linux is freely redistributable, anyone may create a distribution for any intended use.

Antecedents[edit]

Linus Torvalds, principal author of the Linux kernel

The Unix operating system was conceived and implemented in 1969 at AT&T‘s Bell Laboratories in the United States by Ken Thompson, Dennis Ritchie, Douglas McIlroy, and Joe Ossanna.[29] First released in 1971, Unix was written entirely in assembly language as it was common practice at the time. Later, in a key pioneering approach in 1973, it was rewritten in the C programming language by Dennis Ritchie (with exceptions to the kernel and I/O). The availability of a high-level language implementation of Unix made its porting to different computer platforms easier.

Due to an earlier antitrust case forbidding it from entering the computer business, AT&T was required to license the operating system’s source code to anyone who asked.[30] As a result, Unix grew quickly and became widely adopted by academic institutions and businesses. In 1984, AT&T divested itself of Bell Labs; freed of the legal obligation requiring free licensing, Bell Labs began selling Unix as a proprietary product.

The GNU Project, started in 1983 by Richard Stallman, has the goal of creating a “complete Unix-compatible software system” composed entirely offree software. Work began in 1984.[31] Later, in 1985, Stallman started the Free Software Foundation and wrote the GNU General Public License(GNU GPL) in 1989. By the early 1990s, many of the programs required in an operating system (such as libraries, compilers, text editors, a Unix shell, and a windowing system) were completed, although low-level elements such as device drivers, daemons, and the kernel were stalled and incomplete.[32][not in citation given]

Linus Torvalds has stated that if the GNU kernel had been available at the time (1991), he would not have decided to write his own.[33]

Although not released until 1992 due to legal complications, development of 386BSD, from which NetBSD, OpenBSD and FreeBSD descended, predated that of Linux. Torvalds has also stated that if 386BSD had been available at the time, he probably would not have created Linux.[34]

MINIX was created by a computer science professor Andrew S. Tanenbaum and released in 1987 as a minimal Unix-like operating system targeted at students and others who wanted to learn the operating system principles. Although the complete source code of MINIX was freely available, the licensing terms prevented it from being free software until the licensing changed in April 2000.[35]

Creation[edit]

In 1991, while attending the University of Helsinki, Torvalds became curious about operating systems[36] and frustrated by the licensing of MINIX, which at the time limited it to educational use only.[35] He began to work on his own operating system kernel, which eventually became the Linux kernel.

Torvalds began the development of the Linux kernel on MINIX and applications written for MINIX were also used on Linux. Later, Linux matured and further Linux kernel development took place on Linux systems.[37] GNU applications also replaced all MINIX components, because it was advantageous to use the freely available code from the GNU Project with the fledgling operating system; code licensed under the GNU GPL can be reused in other projects as long as they also are released under the same or a compatible license. Torvalds initiated a switch from his original license, which prohibited commercial redistribution, to the GNU GPL.[38] Developers worked to integrate GNU components with the Linux kernel, making a fully functional and free operating system.[32]

Naming[edit]

5.25-inch floppy discs holding a very early version of Linux

Linus Torvalds had wanted to call his invention Freax, a portmanteau of “free”, “freak”, and “x” (as an allusion to Unix). During the start of his work on the system, he stored the files under the name “Freax” for about half of a year. Torvalds had already considered the name “Linux,” but initially dismissed it as too egotistical.[39]

In order to facilitate development, the files were uploaded to the FTP server (ftp.funet.fi) of FUNET in September 1991. Ari Lemmke, Torvald’s coworker at the Helsinki University of Technology (HUT) who was one of the volunteer administrators for the FTP server at the time, did not think that “Freax” was a good name. So, he named the project “Linux” on the server without consulting Torvalds.[39] Later, however, Torvalds consented to “Linux”.

To demonstrate how the word “Linux” should be pronounced (Listeni/ˈlɪnəks/ lin-əks[9][10]), Torvalds included an audio guide (About this sound listen ) with the kernel source code.[40] Another variant of pronunciation is /ˈlnəks/ lyn-əks.[10][11]

Commercial and popular uptake[edit]

Main article: Linux adoption

Ubuntu, a popular Linux distribution

Nexus 5X running Android

Adoption of Linux in production environments, rather than being used only by hobbyists, started to take off first in the mid-1990s in the supercomputing community, where organizations such as NASA started to replace their increasingly expensive machines with clusters of inexpensive commodity computers running Linux. Commercial use followed when Dell and IBM, followed by Hewlett-Packard, started offering Linux support to escape Microsoft‘s monopoly in the desktop operating system market.[41]

Today, Linux systems are used throughout computing, from embedded systems to supercomputers,[21][42] and have secured a place inserver installations such as the popular LAMP application stack.[43] Use of Linux distributions in home and enterprise desktops has been growing.[44][45][46][47][48][49][50] Linux distributions have also become popular in the netbook market, with many devices shipping with customized Linux distributions installed, and Google releasing their own Chrome OS designed for netbooks.

Linux’s greatest success in the consumer market is perhaps the mobile device market, with Android being one of the most dominant operating systems on smartphones and very popular on tablets and, more recently, on wearables. Linux gaming is also on the rise withValve showing its support for Linux and rolling out its own gaming oriented Linux distribution. Linux distributions have also gained popularity with various local and national governments, such as the federal government of Brazil.[51]

Current development[edit]

Torvalds continues to direct the development of the kernel.[52] Stallman heads the Free Software Foundation,[53] which in turn supports the GNU components.[54] Finally, individuals and corporations develop third-party non-GNU components. These third-party components comprise a vast body of work and may include both kernel modules and user applications and libraries.

Linux vendors and communities combine and distribute the kernel, GNU components, and non-GNU components, with additional package management software in the form of Linux distributions.

Design[edit]

A Linux-based system is a modular Unix-like operating system, deriving much of its basic design from principles established in Unix during the 1970s and 1980s. Such a system uses a monolithic kernel, the Linux kernel, which handles process control, networking, access to the peripherals, and file systems. Device drivers are either integrated directly with the kernel, or added as modules that are loaded while the system is running.[55]

Separate projects that interface with the kernel provide much of the system’s higher-level functionality. The GNU userland is an important part of most Linux-based systems, providing the most common implementation of the C library, a popular CLI shell, and many of the common Unix tools which carry out many basic operating system tasks. Thegraphical user interface (or GUI) used by most Linux systems is built on top of an implementation of the X Window System.[56] More recently, the Linux community seeks to advance to Wayland as the new display server protocol in place of X11; Ubuntu, however, develops Mir instead of Wayland.[57]

Various layers within Linux, also showing separation between the userland and kernel space
User mode User applications For example, bash, LibreOffice, Apache OpenOffice, Blender, 0 A.D., Mozilla Firefox, etc.
Low-level system components: System daemons:
systemd, runit, logind, networkd, soundd, …
Windowing system:
X11, Wayland, Mir,SurfaceFlinger (Android)
Other libraries:
GTK+, Qt, EFL, SDL, SFML, FLTK, GNUstep, etc.
Graphics:
Mesa,AMD Catalyst, …
C standard library open(), exec(), sbrk(), socket(), fopen(), calloc(), … (up to 2000 subroutines)
glibc aims to be POSIX/SUS-compatible, uClibc targets embedded systems, bionic written for Android, etc.
Kernel mode Linux kernel stat, splice, dup, read, open, ioctl, write, mmap, close, exit, etc. (about 380 system calls)
The Linux kernel System Call Interface (SCI, aims to be POSIX/SUS-compatible)
Process scheduling
subsystem
IPC
subsystem
Memory management
subsystem
Virtual files
subsystem
Network
subsystem
Other components: ALSA, DRI, evdev, LVM, device mapper, Linux Network Scheduler, Netfilter
Linux Security Modules: SELinux, TOMOYO, AppArmor, Smack
Hardware (CPU, main memory, data storage devices, etc.)

Installed components of a Linux system include the following:[56][58]

  • A bootloader, for example GNU GRUB, LILO, SYSLINUX, Coreboot or Gummiboot. This is a program that loads the Linux kernel into the computer’s main memory, by being executed by the computer when it is turned on and after the firmware initialization is performed.
  • An init program, such as the traditional sysvinit and the newer systemd, OpenRC and Upstart. This is the first process launched by the Linux kernel, and is at the root of the process tree: in other terms, all processes are launched through init. It starts processes such as system services and login prompts (whether graphical or in terminal mode).
  • Software libraries, which contain code that can be used by running processes. On Linux systems using ELF-format executable files, the dynamic linker that manages use of dynamic libraries is known as ld-linux.so. If the system is set up for the user to compile software themselves, header files will also be included to describe the interface of installed libraries. Beside the most commonly used software library on Linux systems, the GNU C Library (glibc), there are numerous other libraries.
  • User interface programs such as command shells or windowing environments.

User interface[edit]

Bash, a shell developed by GNU[59] and widely used in Linux

The user interface, also known as the shell, is either a command-line interface (CLI), a graphical user interface (GUI), or through controls attached to the associated hardware, which is common for embedded systems. For desktop systems, the default mode is usually a graphical user interface, although the CLI is available through terminal emulatorwindows or on a separate virtual console.

CLI shells are the text-based user interfaces, which use text for both input and output. The dominant shell used in Linux is the GNU Bourne-Again Shell (bash), originally developed for the GNU project. Most low-level Linux components, including various parts of the userland, use the CLI exclusively. The CLI is particularly suited for automation of repetitive or delayed tasks, and provides very simple inter-process communication.

On desktop systems, the most popular user interfaces are the GUI shells, packaged together with extensive desktop environments, such as the K Desktop Environment (KDE), GNOME, MATE, Cinnamon, Unity, LXDE, Pantheon andXfce, though a variety of additional user interfaces exist. Most popular user interfaces are based on the X Window System, often simply called “X”. It provides network transparency and permits a graphical application running on one system to be displayed on another where a user may interact with the application; however, certain extensions of the X Window System are not capable of working over the network.[60] Several popular X display servers exist, with the reference implementation, X.Org Server, being the most popular.

Several types of window managers exist for X11, including tiling, dynamic, stacking and compositing. Window managers provide means to control the placement and appearance of individual application windows, and interact with the X Window System. Simpler X window managers such as dwm or ratpoison provide a minimalist functionality, while more elaborate window managers such as FVWM, Enlightenment or Window Maker provide more features such as a built-in taskbar and themes, but are still lightweight when compared to desktop environments. Desktop environments include window managers as part of their standard installations, such as Mutter (GNOME), KWin (KDE) or Xfwm (xfce), although users may choose to use a different window manager if preferred.

Wayland is a display server protocol intended as a replacement for the X11 protocol; as of 2014, Wayland has not received wider adoption. Unlike X11, Wayland does not need an external window manager and compositing manager. Therefore, a Wayland compositor takes the role of the display server, window manager and compositing manager. Weston is the reference implementation of Wayland, while GNOME’s Mutter and KDE’s KWin are being ported to Wayland as standalone display servers. Enlightenment has already been successfully ported to Wayland since version 19.

Video input infrastructure[edit]

Main article: Video4Linux

Linux currently has two modern kernel-userspace APIs for handing video input devices: V4L2 API for video streams and radio, and DVB API for digital TV reception.[61]

Due to the complexity and diversity of different devices, and due to the large amount of formats and standards handled by those APIs, this infrastructure needs to evolve to better fit other devices. Also, a good userspace device library is the key of the success for having userspace applications to be able to work with all formats supported by those devices.[62][63]

Development[edit]

Simplified history of Unix-like operating systems. Linux shares similar architecture and concepts (as part of the POSIX standard) but does not share non-free source code with the original Unix or MINIX.

The primary difference between Linux and many other popular contemporary operating systems is that the Linux kernel and other components are free and open-source software. Linux is not the only such operating system, although it is by far the most widely used.[64]Some free and open-source software licenses are based on the principle of copyleft, a kind of reciprocity: any work derived from a copyleft piece of software must also be copyleft itself. The most common free software license, the GNU General Public License (GPL), is a form of copyleft, and is used for the Linux kernel and many of the components from the GNU Project.

Linux based distributions are intended by developers for interoperability with other operating systems and established computing standards. Linux systems adhere to POSIX,[65] SUS,[66]LSB, ISO, and ANSI standards where possible, although to date only one Linux distribution has been POSIX.1 certified, Linux-FT.[67][68]

Free software projects, although developed through collaboration, are often produced independently of each other. The fact that the software licenses explicitly permit redistribution, however, provides a basis for larger scale projects that collect the software produced by stand-alone projects and make it available all at once in the form of a Linux distribution.

Many Linux distributions, or “distros”, manage a remote collection of system software and application software packages available for download and installation through a network connection. This allows users to adapt the operating system to their specific needs. Distributions are maintained by individuals, loose-knit teams, volunteer organizations, and commercial entities. A distribution is responsible for the default configuration of the installed Linux kernel, general system security, and more generally integration of the different software packages into a coherent whole. Distributions typically use a package manager such as apt, yum, zypper, pacman or portage to install, remove and update all of a system’s software from one central location.

Community[edit]

A distribution is largely driven by its developer and user communities. Some vendors develop and fund their distributions on a volunteer basis, Debian being a well-known example. Others maintain a community version of their commercial distributions, as Red Hat does with Fedora and SUSE does with openSUSE.

In many cities and regions, local associations known as Linux User Groups (LUGs) seek to promote their preferred distribution and by extension free software. They hold meetings and provide free demonstrations, training, technical support, and operating system installation to new users. Many Internet communities also provide support to Linux users and developers. Most distributions and free software / open-source projects have IRC chatrooms or newsgroups. Online forums are another means for support, with notable examples being LinuxQuestions.org and the various distribution specific support and community forums, such as ones for Ubuntu, Fedora, and Gentoo. Linux distributions host mailing lists; commonly there will be a specific topic such as usage or development for a given list.

There are several technology websites with a Linux focus. Print magazines on Linux often include cover disks including software or even complete Linux distributions.[69][70]

Although Linux distributions are generally available without charge, several large corporations sell, support, and contribute to the development of the components of the system and of free software. An analysis of the Linux kernel showed 75 percent of the code from December 2008 to January 2010 was developed by programmers working for corporations, leaving about 18 percent to volunteers and 7% unclassified.[71] Major corporations that provide contributions include Dell, IBM, HP, Oracle, Sun Microsystems (now part of Oracle), SUSE, and Nokia. A number of corporations, notably Red Hat, Canonical, and SUSE, have built a significant business around Linux distributions.

The free software licenses, on which the various software packages of a distribution built on the Linux kernel are based, explicitly accommodate and encourage commercialization; the relationship between a Linux distribution as a whole and individual vendors may be seen as symbiotic. One common business model of commercial suppliers is charging for support, especially for business users. A number of companies also offer a specialized business version of their distribution, which adds proprietary support packages and tools to administer higher numbers of installations or to simplify administrative tasks.

Another business model is to give away the software in order to sell hardware. This used to be the norm in the computer industry, with operating systems such as CP/M, Apple DOS and versions of Mac OS prior to 7.6 freely copyable (but not modifiable). As computer hardware standardized throughout the 1980s, it became more difficult for hardware manufacturers to profit from this tactic, as the OS would run on any manufacturer’s computer that shared the same architecture.

Programming on Linux[edit]

Linux distributions support dozens of programming languages. The original development tools used for building both Linux applications and operating system programs are found within the GNU toolchain, which includes the GNU Compiler Collection (GCC) and the GNU build system. Amongst others, GCC provides compilers for Ada, C, C++, Go andFortran. Many programming languages have a cross-platform reference implementation that supports Linux, for example PHP, Perl, Ruby, Python, Java, Go, Rust and Haskell. First released in 2003, the LLVM project provides an alternative cross-platform open-source compiler for many languages. Proprietary compilers for Linux include the Intel C++ Compiler, Sun Studio, and IBM XL C/C++ Compiler. BASIC in the form of Visual Basic is supported in such forms as Gambas, FreeBASIC, and XBasic, and in terms of terminal programming or QuickBASIC or Turbo BASIC programming in the form of QB64.

A common feature of Unix-like systems, Linux includes traditional specific-purpose programming languages targeted at scripting, text processing and system configuration and management in general. Linux distributions support shell scripts, awk, sed and make. Many programs also have an embedded programming language to support configuring or programming themselves. For example, regular expressions are supported in programs like grep, or locate, while advanced text editors, like GNU Emacs, have a complete Lispinterpreter built-in.

Most distributions also include support for PHP, Perl, Ruby, Python and other dynamic languages. While not as common, Linux also supports C# (via Mono), Vala, and Scheme. A number of Java Virtual Machines and development kits run on Linux, including the original Sun Microsystems JVM (HotSpot), and IBM’s J2SE RE, as well as many open-source projects like Kaffe and JikesRVM.

GNOME and KDE are popular desktop environments and provide a framework for developing applications. These projects are based on the GTK+ and Qt widget toolkits, respectively, which can also be used independently of the larger framework. Both support a wide variety of languages. There are a number of Integrated development environments available including Anjuta, Code::Blocks, CodeLite, Eclipse, Geany, ActiveState Komodo, KDevelop, Lazarus, MonoDevelop, NetBeans, and Qt Creator, while the long-established editors Vim, nano and Emacs remain popular.[72]

Hardware support[edit]

Linux is ubiquitously found on various types of hardware.

The Linux kernel is a widely ported operating system kernel, available for devices ranging from mobile phones to supercomputers; it runs on a highly diverse range of computer architectures, including the hand-held ARM-based iPAQ and the IBM mainframes System z9 or System z10.[73] Specialized distributions and kernel forks exist for less mainstream architectures; for example, the ELKS kernel fork can run on Intel 8086 or Intel 80286 16-bit microprocessors, while the µClinux kernel fork may run on systems without a memory management unit. The kernel also runs on architectures that were only ever intended to use a manufacturer-created operating system, such as Macintosh computers (with both PowerPC and Intel processors),PDAs, video game consoles, portable music players, and mobile phones.

There are several industry associations and hardware conferences devoted to maintaining and improving support for diverse hardware under Linux, such as FreedomHEC. Over time, support for different hardware has improved in Linux, resulting in any off-the-shelf purchase having a “good chance” of being compatible.[74]

Uses[edit]

Beside the Linux distributions designed for general-purpose use on desktops and servers, distributions may be specialized for different purposes including: computer architecturesupport, embedded systems, stability, security, localization to a specific region or language, targeting of specific user groups, support for real-time applications, or commitment to a given desktop environment. Furthermore, some distributions deliberately include only free software. As of 2015, over four hundred Linux distributions are actively developed, with about a dozen distributions being most popular for general-purpose use.[75]

Desktop[edit]

Visible software components of the Linux desktop stack include the display server,widget engines, and some of the more widespread widget toolkits. There are also components not directly visible to end users, including D-Bus and PulseAudio.

The popularity of Linux on standard desktop computers and laptops has been increasing over the years.[76] Most modern distributions include a graphical user environment, with, as of February 2015, the two most popular environments being the KDE Plasma Desktop andXfce.[77]

No single official Linux desktop exists: rather desktop environments and Linux distributions select components from a pool of free and open-source software with which they construct a GUI implementing some more or less strict design guide. GNOME, for example, has its human interface guidelines as a design guide, which gives the human–machine interface an important role, not just when doing the graphical design, but also when considering people withdisabilities, and even when focusing on security.[78]

The collaborative nature of free software development allows distributed teams to performlanguage localization of some Linux distributions for use in locales where localizing proprietary systems would not be cost-effective. For example, the Sinhalese language version of theKnoppix distribution became available significantly before Microsoft translated Windows XP into Sinhalese.[79] In this case the Lanka Linux User Group played a major part in developing the localized system by combining the knowledge of university professors, linguists, and local developers.

Performance and applications[edit]

The performance of Linux on the desktop has been a controversial topic;[citation needed] for example in 2007 Con Kolivas accused the Linux community of favoring performance on servers. He quit Linux kernel development out of frustration with this lack of focus on the desktop, and then gave a “tell all” interview on the topic.[80] Since then a significant amount of development has focused on improving the desktop experience. Projects such as Upstart and systemd aim for a faster boot time; the Wayland and Mir projects aim at replacing X11 while enhancing desktop performance, security and appearance.[81]

Many popular applications are available for a wide variety of operating systems. For example, Mozilla Firefox, OpenOffice.org/LibreOffice and Blender have downloadable versions for all major operating systems. Furthermore, some applications initially developed for Linux, such as Pidgin, and GIMP, were ported to other operating systems (including Windowsand Mac OS X) due to their popularity. In addition, a growing number of proprietary desktop applications are also supported on Linux,[82] such as Autodesk Maya, Softimage XSI and Apple Shake in the high-end field of animation and visual effects; see the list of proprietary software for Linux for more details. There are also several companies that have ported their own or other companies’ games to Linux, with Linux also being a supported platform on both the popular Steam and Desura digital-distribution services.[83]

Many other types of applications available for Microsoft Windows and Mac OS X also run on Linux. Commonly, either a free software application will exist which does the functions of an application found on another operating system, or that application will have a version that works on Linux, such as with Skype and some video games like Dota 2 and Team Fortress 2. Furthermore, the Wine project provides a Windows compatibility layer to run unmodified Windows applications on Linux. It is sponsored by commercial interests including CodeWeavers, which produces a commercial version of the software. Since 2009, Google has also provided funding to the Wine project.[84][85] CrossOver, a proprietary solution based on the open-source Wine project, supports running Windows versions of Microsoft Office, Intuit applications such as Quicken and QuickBooks, Adobe Photoshopversions through CS2, and many popular games such as World of Warcraft. In other cases, where there is no Linux port of some software in areas such as desktop publishing[86]and professional audio,[87][88][89] there is equivalent software available on Linux.

Components and installation[edit]

Besides externally visible components, such as X window managers, a non-obvious but quite central role is played by the programs hosted by freedesktop.org, such as D-Bus orPulseAudio; both major desktop environments (GNOME and KDE) include them, each offering graphical front-ends written using the corresponding toolkit (GTK+ or Qt). A display server is another component, which for the longest time has been communicating in the X11 display server protocol with its clients; prominent software talking X11 includes theX.Org Server and Xlib. Frustration over the cumbersome X11 core protocol, and especially over its numerous extensions, has led to the creation of a new display server protocol,Wayland.

Installing, updating and removing software in Linux is typically done through the use of package managers such as the Synaptic Package Manager, PackageKit, and Yum Extender. While most major Linux distributions have extensive repositories, often containing tens of thousands of packages, not all the software that can run on Linux is available from the official repositories. Alternatively, users can install packages from unofficial repositories, download pre-compiled packages directly from websites, or compile the source code by themselves. All these methods come with different degrees of difficulty; compiling the source code is in general considered a challenging process for new Linux users, but it is hardly needed in modern distributions and is not a method specific to Linux.

Netbooks[edit]

Linux distributions have also become popular in the netbook market, with many devices such as the ASUS Eee PC and Acer Aspire One shipping with customized Linux distributions installed.[90]

In 2009, Google announced its Chrome OS as a minimal Linux-based operating system, using the Chrome browser as the main user interface. Chrome OS does not run any non-web applications, except for the bundled file manager and media player (a certain level of support for Android applications was added in later versions).[91] The netbooks that shipped with the operating system, termed Chromebooks, started appearing on the market in June 2011.[92]

Servers, mainframes and supercomputers[edit]

Broad overview of the LAMP software bundle, displayed here together with Squid. A high-performance and high-availability web server solution providing security in a hostile environment.

Linux distributions have long been used as server operating systems, and have risen to prominence in that area; Netcraft reported in September 2006, that eight of the ten most reliable internet hosting companies ran Linux distributions on their web servers.[93] In June 2008, Linux distributions represented five of the top ten, FreeBSD three of ten, and Microsofttwo of ten;[94] since February 2010, Linux distributions represented six of the top ten, FreeBSD two of ten, and Microsoft one of ten.[95]

Linux distributions are the cornerstone of the LAMP server-software combination (Linux,Apache, MariaDB/MySQL, Perl/PHP/Python) which has achieved popularity among developers, and which is one of the more common platforms for website hosting.[96]

Linux distributions have become increasingly popular on mainframes in the last decade partly due to pricing and the open-source model.[21][citation needed] In December 2009, computer giantIBM reported that it would predominantly market and sell mainframe-based Enterprise Linux Server.[97]

Linux distributions are also most commonly used as operating systems for supercomputers; in the decade since Earth Simulator supercomputer, all the fastest supercomputers have used Linux. As of November 2015, 98.8% of the world’s 500 fastest supercomputers run some variant of Linux,[98] including the top 207.[99]

Smart devices[edit]

Android smartphones

Several operating systems for smart devices, such as smartphones, tablet computers, smart TVs, and in-vehicle infotainment (IVI) systems, are based on Linux. Major platforms for such systems include Android, Firefox OS, Mer and Tizen.

Android has become the dominant mobile operating system for smartphones, during the second quarter of 2013, 79.3% of smartphones sold worldwide used Android.[100] Android is also a popular operating system for tablets, and Android smart TVs and in-vehicle infotainment systems have also appeared in the market.

Cell phones and PDAs running Linux on open-source platforms became more common from 2007; examples include the Nokia N810,Openmoko‘s Neo1973, and the Motorola ROKR E8. Continuing the trend, Palm (later acquired by HP) produced a new Linux-derived operating system, webOS, which is built into its line of Palm Pre smartphones.

Nokia‘s Maemo, one of the earliest mobile operating systems, was based on Debian.[101] It was later merged with Intel‘s Moblin, another Linux-based operating system, to form MeeGo.[102] The project was later terminated in favor of Tizen, an operating system targeted at mobile devices as well as in-vehicle infotainment (IVI). Tizen is a project within The Linux Foundation. Several Samsung products are already running Tizen, Samsung Gear 2 being the most significant example.[103]Samsung Z smartphones will use Tizen instead of Android.[104]

As a result of MeeGo’s termination, the Mer project forked the MeeGo codebase to create a basis for mobile-oriented operating systems.[105] In July 2012, Jolla announced Sailfish OS, their own mobile operating system built upon Mer technology.

Mozilla’s Firefox OS consists of the Linux kernel, a hardware abstraction layer, a web standards based runtime environment and user interface, and an integrated web browser.[106]

Canonical has released Ubuntu Touch, its own mobile operating system that aims to bring convergence to the user experience on the operating system and its desktop counterpart, Ubuntu. The operating system also provides a full Ubuntu desktop when connected to an external monitor.[107]

Embedded devices[edit]

The Jolla Phone has the Linux-based Sailfish OS

Nokia X, a smartphone that runs Linux kernel

Due to its low cost and ease of customization, Linux is often used in embedded systems. In the non-mobile telecommunications equipment sector, the majority of customer-premises equipment (CPE) hardware runs some Linux-based operating system. OpenWrt is a community driven example upon which many of the OEM firmwares are based.

For example, the popular TiVo digital video recorder also uses a customized Linux,[109] as do several network firewalls and routers from such makers as Cisco/Linksys. The Korg OASYS, the Korg KRONOS, the Yamaha Motif XS/Motif XF music workstations,[110] Yamaha S90XS/S70XS, Yamaha MOX6/MOX8 synthesizers, Yamaha Motif-Rack XS tone generator module, and Roland RD-700GX digital piano also run Linux. Linux is also used instage lighting control systems, such as the WholeHogIII console.[111]

Gaming[edit]

Main article: Linux gaming

There had been several games that run on traditional desktop Linux, and many of which originally written for desktop OS. However, due to most game developers not paying attention to such a small market as desktop Linux, only a few prominent games have been available for desktop Linux. On the other hand, as a popular mobile platform, Android has gained much developer interest and there are many games available for Android.

On 14 February 2013, Valve released a Linux version of Steam, a popular game distribution platform on PC.[112] Many Steam games were ported to Linux.[113] On 13 December 2013, Valve released SteamOS, a gaming oriented OS based on Debian, for beta testing, and has plans to ship Steam Machines as a gaming and entertainment platform.[114] Valve has also developed VOGL, an OpenGL debugger intended to aid video game development,[115] as well as porting its Source game engine to desktop Linux.[116] As a result of Valve’s effort, several prominent games such as DotA 2, Team Fortress 2, Portal, Portal 2 and Left 4 Dead 2 are now natively available on desktop Linux.

On 31 July 2013, Nvidia released Shield as an attempt to use Android as a specialized gaming platform.[117]

Specialized uses[edit]

Due to the flexibility, customizability and free and open-source nature of Linux, it becomes possible to highly tune Linux for a specific purpose. There are two main methods for creating a specialized Linux distribution: building from scratch or from a general-purpose distribution as a base. The distributions often used for this purpose include Debian, Fedora, Ubuntu (which is itself based on Debian), Arch Linux, Gentoo, and Slackware. In contrast, Linux distributions built from scratch do not have general-purpose bases; instead, they focus on the JeOS philosophy by including only necessary components and avoiding resource overhead caused by components considered redundant in the distribution’s use cases.

Home theater PC[edit]

A home theater PC (HTPC) is a PC that is mainly used as an entertainment system, especially a Home theater system. It is normally connected to a television, and often an additional audio system.

OpenELEC, a Linux distribution that incorporates the media center software Kodi, is an OS tuned specifically for an HTPC. Having been built from the ground up adhering to the JeOS principle, the OS is very lightweight and very suitable for the confined usage range of an HTPC.

There are also special editions of Linux distributions that include the MythTV media center software, such as Mythbuntu, a special edition of Ubuntu.

Digital security[edit]

Kali Linux is a Debian-based Linux distribution designed for digital forensics and penetration testing. It comes preinstalled with several software applications for penetration testing and identifying security exploits.[118] The Ubuntu derivative BackBox provides pre-installed security and network analysis tools for ethical hacking.

There are many Linux distributions created with privacy, secrecy, network anonymity and information security in mind, including Tails, Tin Hat Linux and Tinfoil Hat Linux.Lightweight Portable Security is a distribution based on Arch Linux and developed by the United States Department of Defense. Tor-ramdisk is a minimal distribution created solely to host the network anonymity software Tor.

System rescue[edit]

Linux Live CD sessions have long been used as a tool for recovering data from a broken computer system and for repairing the system. Building upon that idea, several Linux distributions tailored for this purpose have emerged, most of which use GParted as a partition editor, with additional data recovery and system repair software:

In space[edit]

SpaceX uses multiple redundant flight computers in a fault-tolerant design in the Falcon 9 rocket. Each Merlin engine is controlled by three voting computers, with two physical processors per computer that constantly check each other’s operation. Linux is not inherently fault-tolerant (no operating system is, as it is a function of the whole system including the hardware), but the flight computer software makes it so for its purpose.[119] For flexibility, commercial off-the-shelf parts and system-wide “radiation-tolerant” design are used instead of radiation hardened parts.[119] As of June 2015, SpaceX has made 19 launches of the Falcon 9 since 2010, out of which 18 have successfully delivered their primary payloads to Earth orbit, including some support missions for the International Space Station.

In addition, Windows was used as an operating system on non-mission critical systems—​​laptops used on board the space station, for example—​​but it has been replaced with Linux; the first Linux-powered humanoid robot is also undergoing in-flight testing.[120]

The Jet Propulsion Laboratory has used Linux for a number of years “to help with projects relating to the construction of unmanned space flight and deep space exploration”;NASA uses Linux in robotics in the Mars rover, and Ubuntu Linux to “save data from satellites”.[121]

Education[edit]

Linux distributions have been created to provide hands-on experience with coding and source code to students, on devices such as the Raspberry Pi. In addition to producing a practical device, the intention is to show students “how things work under the hood”.

The Ubuntu derivatives Edubuntu and The Linux Schools Project, as well as the Debian derivative Skolelinux, provide education-oriented software packages. They also include tools for administering and building school computer labs and computer-based classrooms, such as the Linux Terminal Server Project (LTSP).

Others[edit]

Instant WebKiosk and Webconverger are browser-based Linux distributions often used in web kiosks and digital signage. Thinstation is a minimalist distribution designed for thin clients. Rocks Cluster Distribution is tailored for high-performance computing clusters.

There are general-purpose Linux distributions that target a specific audience, such as users of a specific language or geographical area. Such examples include Ubuntu Kylin for Chinese language users and BlankOn targeted at Indonesians. Profession-specific distributions include Ubuntu Studio for media creation and DNALinux for bioinformatics. There is also a Muslim-oriented distribution of the name Sabily, as well as an Arabic-focused distribution called Ojuba Linux that consequently also provides some Islamic tools. Certain organizations use slightly specialized Linux distributions internally, including GendBuntu used by the French National Gendarmerie, Goobuntu used internally by Google, and Astra Linux developed specifically for the Russian army.

Market share and uptake[edit]

Main article: Linux adoption

Many quantitative studies of free/open-source software focus on topics including market share and reliability, with numerous studies specifically examining Linux.[122] The Linux market is growing rapidly, and the revenue of servers, desktops, and packaged software running Linux was expected to[needs update] exceed $35.7 billion by 2008.[123] Analysts and proponents attribute the relative success of Linux to its security, reliability, low cost, and freedom from vendor lock-in.[124][125]

Desktops and laptops
According to web server statistics, as of March 2015, the estimated market share of Linux on desktop computers is around 1.5%. In comparison, Microsoft Windows has a market share of around 91.5%, while Mac OS covers around 7%.[22]
Web servers
W3Cook publishes stats that use the top one million Alexa domains,[126] which as of May 2015 estimate that 96.55% of web servers run Linux, 1.73% run Windows, and 1.72% run FreeBSD.[127] W3Techs publishes stats that use the top ten million Alexa domains, which is updated every month[128] and as of May 2015 estimates that 32.6% of web servers run Windows, with the rest being Linux or Unix.[129] IDC‘s Q1 2007 report indicated that Linux held 12.7% of the overall server market at that time;[130] this estimate was based on the number of Linux servers sold by various companies, and did not include server hardware purchased separately that had Linux installed on it later. In September 2008, Microsoft’s CEO Steve Ballmer stated that 60% of web servers ran Linux, versus 40% that ran Windows Server.[131]
Mobile devices
Android, which is based on the Linux kernel, has become the dominant operating system for smartphones. During the second quarter of 2013, 79.3% of smartphones sold worldwide used Android.[100] Android is also a popular operating system for tablets, being responsible for more than 60% of tablet sales as of 2013.[132] According to web server statistics, as of December 2014 Android has a market share of about 46%, with iOS holding 45%, and the remaining 9% attributed to various niche platforms.[133]
Film production
For years Linux has been the platform of choice in the film industry. The first major film produced on Linux servers was 1997’s Titanic.[134][135] Since then major studios including DreamWorks Animation, Pixar, Weta Digital, and Industrial Light & Magic have migrated to Linux.[136][137][138] According to the Linux Movies Group, more than 95% of the servers and desktops at large animation and visual effects companies use Linux.[139]
Use in government
Linux distributions have also gained popularity with various local and national governments. The federal government of Brazil is well known for its support for Linux.[140][141]News of the Russian military creating its own Linux distribution has also surfaced, and has come to fruition as the G.H.ost Project.[142] The Indian state of Kerala has gone to the extent of mandating that all state high schools run Linux on their computers.[143][144] China uses Linux exclusively as the operating system for its Loongson processor family to achieve technology independence.[145] In Spain, some regions have developed their own Linux distributions, which are widely used in education and official institutions, likegnuLinEx in Extremadura and Guadalinex in Andalusia. France and Germany have also taken steps toward the adoption of Linux.[146] North Korea’s Red Star OS, developed since 2002, is based on a version of Fedora Linux.[147]

Copyright, trademark, and naming[edit]

Linux kernel is licensed under the GNU General Public License (GPL), version 2. The GPL requires that anyone who distributes software based on source code under this license, must make the originating source code (and any modifications) available to the recipient under the same terms.[148] Other key components of a typical Linux distribution are also mainly licensed under the GPL, but they may use other licenses; many libraries use the GNU Lesser General Public License (LGPL), a more permissive variant of the GPL, and the X.org implementation of the X Window System uses the MIT License.

Torvalds states that the Linux kernel will not move from version 2 of the GPL to version 3.[149][150] He specifically dislikes some provisions in the new license which prohibit the use of the software in digital rights management.[151] It would also be impractical to obtain permission from all the copyright holders, who number in the thousands.[152]

A 2001 study of Red Hat Linux 7.1 found that this distribution contained 30 million source lines of code.[153] Using the Constructive Cost Model, the study estimated that this distribution required about eight thousand man-years of development time. According to the study, if all this software had been developed by conventional proprietary means, it would have cost about $1.48 billion (2016 US dollars) to develop in the United States.[153] Most of the source code (71%) was written in the C programming language, but many other languages were used, including C++, Lisp, assembly language, Perl, Python, Fortran, and various shell scripting languages. Slightly over half of all lines of code were licensed under the GPL. The Linux kernel itself was 2.4 million lines of code, or 8% of the total.[153]

In a later study, the same analysis was performed for Debian version 4.0 (etch, which was released in 2007).[154] This distribution contained close to 283 million source lines of code, and the study estimated that it would have required about seventy three thousand man-years and cost US$8.18 billion (in 2016 dollars) to develop by conventional means.

The name “Linux” is also used for a laundry detergent made by Swiss company Rösch.[155]

In the United States, the name Linux is a trademark registered to Linus Torvalds.[8] Initially, nobody registered it, but on 15 August 1994, William R. Della Croce, Jr. filed for the trademark Linux, and then demanded royalties from Linux distributors. In 1996, Torvalds and some affected organizations sued him to have the trademark assigned to Torvalds, and, in 1997, the case was settled.[156] The licensing of the trademark has since been handled by the Linux Mark Institute. Torvalds has stated that he trademarked the name only to prevent someone else from using it. LMI originally charged a nominal sublicensing fee for use of the Linux name as part of trademarks,[157] but later changed this in favor of offering a free, perpetual worldwide sublicense.[158]

The Free Software Foundation prefers GNU/Linux as the name when referring to the operating system as a whole, because it considers Linux to be a variant of the GNU operating system, initiated in 1983 by Richard Stallman, president of the Free Software Foundation.[16][17]

A minority of public figures and software projects other than Stallman and the Free Software Foundation, notably Debian (which had been sponsored by the Free Software Foundation up to 1996[159]), also use GNU/Linux when referring to the operating system as a whole.[109][160][161] Most media and common usage,[original research?] however, refers to this family of operating systems simply as Linux, as do many large Linux distributions (for example, SUSE Linux and Red Hat). As of May 2011, about 8% to 13% of a modern Linux distribution is made of GNU components (the range depending on whether GNOME is considered part of GNU), as determined by counting lines of source code making up Ubuntu’s “Natty” release; meanwhile, about 9% is taken by the Linux kernel.[162]

See also[edit]

Notes[edit]

  1. Jump up^ GNU is the primary userland used in nearly all Linux distros.[2][3][4] The GNU userland contains system daemons, user applications, the GUI, and various libraries. GNU Core utilities are an essential part of most distros. Most Linux distributions use the X Window system.[5] Other components of the userland, such as Desktop environment and native packages, vary with the specific distribution and user configuration.[6]
  2. Jump up^ “Linux” trademark is owned by Linus Torvalds[8] and administered by the Linux Mark Institute.

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    Linux
    Tux the penguin

    Tux the penguin, mascot of Linux[1]

    Developer Community
    Written in Primarily C andassembly
    OS family Unix-like
    Working state Current
    Source model Mainly open-source,proprietary software is also available
    Initial release 5 October 1991; 24 years ago
    Marketing target Personal computers,mobile devices,embedded devices,servers, mainframes,supercomputers
    Available in Multilingual
    Platforms Alpha, ARC, ARM,AVR32, Blackfin, C6x,ETRAX CRIS, FR-V,H8/300, Hexagon,Itanium, M32R, m68k,META, Microblaze,MIPS, MN103, Nios II,OpenRISC, PA-RISC,PowerPC, s390,S+core, SuperH,SPARC, TILE64,Unicore32, x86, Xtensa
    Kernel type Monolithic (Linux kernel)
    Userland GNU, various other [a]
    Default user interface Many
    License GPLv2[7] and other free and open-source licenses, except for the “Linux” trademark[b]
    Official website

WINDOWS

Microsoft Windows — семейство проприетарных операционных систем корпорации Microsoft, ориентированных на применение графического интерфейса при управлении. Изначально Windows была всего лишь графической надстройкой для MS-DOS. По состоянию на август 2014 года под управлением операционных систем семейства Windows по данным ресурса NetMarketShare работает более 91% персональных компьютеров. Windows работает на платформах x86, x86-64,IA-64 и ARM. Существовали также версии для DEC Alpha, MIPS, PowerPC и SPARC.

Графические интерфейсы и расширения для DOS

Логотип первых Windows

Первые версии Windows не были полноценными операционными системами, а являлись надстройками к операционной системе DOS и были по сути многофункциональным расширением, добавляя поддержку новых режимов работы процессора, поддержку многозадачности, обеспечивая стандартизацию интерфейсов аппаратного обеспечения и единообразие для пользовательских интерфейсов программ. Предоставляли встроенные средства GDIи USER для создания графического интерфейса. Первые версии Windows вообще состояли из трёх модулей — KERNEL, GDI и USER. Первый из них предоставлял вызовы управления памятью, запуском .EXE-файлов и загрузкой .DLL-файлов, второй — графику, третий — окна. Они работали с процессорами начиная с Intel 8086.

  1. Windows 1.0 (1985)
  2. Windows 2.0 (1987)
  3. Windows 2.1 (Windows 386, 1987) — в системе появилась возможность запуска DOS-приложений в графических окнах, причём каждому приложению предоставлялись полные 640 Кб памяти. Полная поддержка процессора 80286. Появилась поддержка процессоров 80386.
  4. Windows 3.0 (1990) — улучшена поддержка процессоров 80386 и защищённого режима.
  5. Windows 3.1 (1992) — серьёзно переработанная Windows 3.0; устранены UAE (фатальные ошибки прикладных программ), добавлен механизм OLE, печать в режиме WYSIWYG («что видите, то и получите»), шрифты TrueType, изменён диспетчер файлов, добавлены мультимедийные функции.
  6. Windows для рабочих групп (Windows for Workgroups) 3.1/3.11 — первая версия ОС семейства с поддержкой локальных сетей. В системе также испытывались отдельные усовершенствования ядра, применённые позднее в Windows 95.

Семейство Windows 9x

Логотип первой системы семейства Windows 95

Первая система данного семейства Windows 95 была выпущена в 1995 году. Её отличительными особенностями являлись: новый пользовательский интерфейс, поддержка длинных имён файлов, автоматическое определение и конфигурация периферийных устройств Plug and Play, способность исполнять 32-битные приложения и наличие поддержки TCP/IP прямо в системе. Windows 95 использовала вытесняющую многозадачность и выполняла каждое 32-битное приложение в своём адресном пространстве. К данному семейству относятся также Windows 98 и Windows ME.

Логотип второй системы семейства Windows 98

Операционные системы этого семейства не являлись безопасными многопользовательскими системами как Windows NT, поскольку из соображений совместимости вся подсистема пользовательского интерфейса и графики оставалась 16-битной и мало отличалась от той, что в Windows 3.x. Так как этот код не был потокобезопасным, все вызовы в подсистему оборачивались вмьютекс по имени Win16Lock, который, кроме того, ещё и находился всегда в захваченном состоянии во время исполнения 16-битного приложения. Таким образом, «повисание» 16-битного приложения немедленно блокировало всю ОС. Но уже в 1999 году вышло второе исправленное издание. Программный интерфейс был подмножеством Win32 API, поддерживаемым Windows NT, но имел поддержку юникода в очень ограниченном объёме[3]. Также в нём не было должного обеспечения безопасности (списков доступа к объектам и понятия «администратор»). В составе Windows 95 присутствовал MS-DOS 7.0, однако его роль сводилась к обеспечению процесса загрузки и исполнению 16-битных DOS приложений. Исследователи заметили, что ядро Windows 95 — VMM — обращается к DOS под собой, но таких обращений довольно мало, главнейшая функция ядра DOS — файловая система FAT — не использовалась. В целом же интерфейс между VMM и нижележащей DOS никогда не публиковался, и DOS была замечена Эндрю Шульманом (книга «Недокументированный Windows 95») в наличии недокументированных вызовов только для поддержки VMM.

Семейство Windows NT

Логотип семейства Windows NT

Операционные системы этого семейства в настоящее время работают на процессорах с архитектурами x86, x86-64, иItanium, ARM. Ранние версии (до 4.0 включительно) также поддерживали некоторые RISC-процессоры: Alpha, MIPS, иPower PC. Все операционные системы этого семейства являются полностью 32- или 64- битными операционными системами, и не нуждаются в MS-DOS даже для загрузки.

Только в этом семействе представлены операционные системы для серверов. До версии Windows 2000 включительно они выпускались под тем же названием, что и аналогичная версия для рабочих станций, но с добавлением суффикса, например, «Windows NT 4.0 Server» и «Windows 2000 Datacenter Server». Начиная с Windows Server 2003 серверные операционные системы называются добавлением суффикса «Server» и года выпуска.

Логотип Windows 8

  1. Windows NT 3.1 (1993)
  2. Windows NT 3.5 (1994)
  3. Windows NT 3.51 (1995)
  4. Windows NT 4.0 (1996)
  5. Windows 2000 — Windows NT 5.0 (2000)
  6. Windows XP — Windows NT 5.1 (2001)
  7. Windows XP 64-bit Edition — Windows NT 5.2 (2003)
  8. Windows Server 2003 — Windows NT 5.2 (2003)
  9. Windows XP Professional x64 Edition — Windows NT 5.2 (2005)
  10. Windows Vista — Windows NT 6.0 (2006)
  11. Windows Home Server — Windows NT 5.2 (2007)
  12. Windows Server 2008 — Windows NT 6.0 (2008)
  13. Windows Small Business Server — Windows NT 6.0 (2008)
  14. Windows 7 — Windows NT 6.1 (2009)
  15. Windows Server 2008 R2 — Windows NT 6.1 (2009)
  16. Windows Home Server 2011 — Windows NT 6.1 (2011)
  17. Windows 8 — Windows NT 6.2 (2012)
  18. Windows Server 2012 — Windows NT 6.2 (2012)
  19. Windows 8.1 — Windows NT 6.3 (2013)
  20. Windows Server 2012 R2 — Windows NT 6.3 (2013)
  21. Windows 10 — Windows NT 10.0 (2015)

В основу семейства Windows NT положено разделение адресных пространств между процессами. Каждый процесс имеет возможность работать с выделенной ему памятью. Однако он не имеет прав для записи в память других процессов, драйверов и системного кода.

Семейство Windows NT относится к операционным системам с вытесняющей многозадачностью. Разделение процессорного времени между потоками происходит по принципу «карусели». Ядро операционной системы выделяет квант времени (в Windows 2000 квант равен примерно 20 мс) каждому из потоков по очереди при условии, что все потоки имеют одинаковый приоритет. Поток может отказаться от выделенного ему кванта времени. В этом случае система перехватывает у него управление (даже если выделенный квант времени не закончен) и передаёт управление другому потоку. При передаче управления другому потоку система сохраняет состояние всех регистров процессора в особой структуре в оперативной памяти. Эта структура называется контекстом потока. Сохранения контекста потока достаточно для последующего возобновления его работы.

Семейство ОС для смартфонов

Логотип Windows Phone

Это семейство операционных систем реального времени было специально разработано для мобильных устройств. Поддерживаются процессоры ARM, MIPS, SuperH и x86. В отличие от остальных операционных систем Windows, операционные системы этого семейства продаются только в составе готовых устройств, таких как смартфоны, карманные компьютеры, GPS-навигаторы, MP3-проигрыватели и другие. В настоящее время под термином «Windows CE» понимают только ядро операционной системы. Например, Windows Mobile 5.0 включает в себя ядро Windows CE 5.0.

Семейство встраиваемых ОС Windows Embedded

Логотип Windows Embedded

Windows Embedded — это семейство операционных систем реального времени, было специально разработано для применения в различных встраиваемых системах. Ядро системы имеет общее с семейством ОС Windows CE и поддерживает процессоры ARM,MIPS, SuperH и x86.

Windows Embedded включает дополнительные функции по встраиванию, среди которых фильтр защиты от записи (EWF и FBWF), загрузка с флеш-памяти, CD-ROM, сети, использование собственной оболочки системы и т. п.

В отличие от операционных систем Windows, операционные системы этого семейства продаются только в составе готовых устройств, таких как: банкоматы,медицинские приборы, навигационное оборудование, «тонкие» клиенты, VoIP-терминалы, медиапроигрыватели, цифровые рамки (альбомы), кассовые терминалы,платёжные терминалы, роботы, игровые автоматы, музыкальные автоматы и другие.

В настоящее время выпускаются следующие варианты ОС Windows Embedded[4]:

Хронология

Интегрированные программные продукты

Пакет Windows включает в себя «стандартные» приложения[5], такие как браузер (Internet Explorer), почтовый клиент (Outlook Express или Почта Windows), музыкальный и видеопроигрыватель (Проигрыватель Windows Media). С помощью технологий COM и OLE их компоненты могут быть использованы в приложениях сторонних производителей. Эти продукты бесплатны и могут быть свободно скачаны с официального сайта Microsoft, однако для установки некоторых из них необходимо иметь лицензионную версию Windows (верно только для ранних версий до Windows, начиная с Windows 98 являются неотъемлемой частью системы). Запуск этих программ под другими операционными системами возможен только с помощью эмуляторов среды Windows (Wine).

Вокруг факта включения таких «стандартных» продуктов в ОС Windows разгорается много дискуссий и юридических споров, по мнению сторонних разработчиков, это ведёт к отсутствию конкуренции и создает препятствия для распространения конкурирующих продуктов, они же часто ставят под сомнение качество браузера Internet Explorer, объясняя его популярность вхождением в пакет Windows и плохой осведомленностью пользователей о наличии альтернатив.

В 1997 году компания Sun Microsystems подала в суд на компанию за нарушение лицензии на использование технологий Java. В 2001 году Microsoft выплатила штраф и исключила не совместимую с лицензированной виртуальную машину Java из состава своих продуктов[6].

Распространённость

В настоящее время Windows установлена на 91% персональных компьютеров и рабочих станций. По данным компании Net Applications, на август 2014 года рыночная доля Windows составила ▲91,68%.

Среди различных версий Windows по данным W3Schools с августа 2011 года наиболее популярна Windows 7[7] (около 50%).

Распространённость версий Windows по данным различных источников
«GoStats.ru»,
июнь 2011[8]
«Net Market Share»,
июнь 2011[9]
«GoStats.ru»,
август 2014[10]
«Net Market Share»,
август 2014[11]
«GoStats.ru»,
август 2015[12]
Все версии 94.70 % 93.32 % 90.46% 91.68% 84.76%
Windows 10 2.87%
Windows 8 2,4% 12,48% 33,67%
Windows 7 25.89 % 28.68 % 76.72% 51.22% 40.63%
Windows XP 55.44 % 54.04 % 23.89% 6.55%

См. также

Примечания

Литература

Windows

Microsoft Windows (or simply Windows) is a metafamily of graphical operating systems developed, marketed, and sold byMicrosoft. It consists of several families of operating systems, each of which cater to a certain sector of the computing industry. Active Windows families include Windows NT, Windows Embedded and Windows Phone; these may encompass subfamilies, e.g. Windows Embedded Compact (Windows CE) or Windows Server. Defunct Windows families include Windows 9x andWindows Mobile.

Microsoft introduced an operating environment named Windows on November 20, 1985, as a graphical operating system shellfor MS-DOS in response to the growing interest in graphical user interfaces (GUIs).[4] Microsoft Windows came to dominate the world’s personal computer market with over 90% market share, overtaking Mac OS, which had been introduced in 1984. However, since 2012, because of the massive growth of smartphones, Windows sells less than Android, which became the most popular operating system in 2014, when counting all of the computing platforms each operating system runs on; in 2014, the number of Windows devices sold were less than 25% of Android devices sold. However, comparisons across different markets are not fully relevant; and for personal computers, Windows is still the most popular operating system.

As of July 2015, the most recent version of Windows for personal computers, tablets and smartphones is Windows 10. The most recent versions for server computers and embedded devices are respectively Windows Server 2012 R2 and Windows Embedded 8. A specialized version of Windows runs on the Xbox One game console.[5]

The next server version of Windows is Windows Server 2016, which is expected to be released in early 2016.

Genealogy

By marketing role

Microsoft, the developer of Windows, has registered several trademarks each of which denote a family of Windows operating systems that target a specific sector of the computing industry. As of 2014, the following Windows families are being actively developed:

The following Windows families are no longer being developed:

  • Windows 9x: An operating system that targeted consumers market. Discontinued because of suboptimal performance. (PC World called its last version, Windows ME, one of the worst products of all times.)[7] Microsoft now caters to the consumers market with Windows NT.
  • Windows Mobile: The predecessor to Windows Phone, it was a mobile phone operating system. The first version was called Pocket PC 2000; the third version, Windows Mobile 2003 is the first version to adopt the Windows Mobile trademark. The last version is Windows Mobile 6.5.

Version history

The term Windows collectively describes any or all of several generations of Microsoft operating system products. These products are generally categorized as follows:

Early versions

Windows 1.0, the first version, released in 1985

The history of Windows dates back to September 1981, when Chase Bishop, a computer scientist, designed the first model of an electronic device and project Interface Manager was started. It was announced in November 1983 (after the Apple Lisa, but before the Macintosh) under the name “Windows”, but Windows 1.0 was not released until November 1985.[8] Windows 1.0 was to compete with Apple‘s operating system, but achieved little popularity. Windows 1.0 is not a complete operating system; rather, it extends MS-DOS. The shell of Windows 1.0 is a program known as the MS-DOS Executive. Components includedCalculator, Calendar, Cardfile, Clipboard viewer, Clock, Control Panel, Notepad, Paint, Reversi, Terminal and Write. Windows 1.0 does not allow overlapping windows. Instead all windows are tiled. Only modal dialog boxes may appear over other windows.

Windows 2.0 was released in December 1987, and was more popular than its predecessor. It features several improvements to the user interface and memory management.[citation needed] Windows 2.03 changed the OS from tiled windows to overlapping windows. The result of this change led to Apple Computer filing a suit against Microsoft alleging infringement on Apple’s copyrights.[9][10] Windows 2.0 also introduced more sophisticated keyboard shortcuts and could make use of expanded memory.

Windows 2.1 was released in two different versions: Windows/286 and Windows/386. Windows/386 uses the virtual 8086 mode of the Intel 80386 to multitask several DOS programs and the paged memory model to emulate expanded memory using available extended memory. Windows/286, in spite of its name, runs on both Intel 8086 and Intel 80286 processors. It runs in real mode but can make use of the high memory area.[citation needed]

In addition to full Windows-packages, there were runtime-only versions that shipped with early Windows software from third parties and made it possible to run their Windows software on MS-DOS and without the full Windows feature set.

The early versions of Windows are often thought of as graphical shells, mostly because they ran on top of MS-DOS and use it for file system services.[11] However, even the earliest Windows versions already assumed many typical operating system functions; notably, having their own executable file format and providing their own device drivers (timer, graphics, printer, mouse, keyboard and sound). Unlike MS-DOS, Windows allowed users to execute multiple graphical applications at the same time, through cooperative multitasking. Windows implemented an elaborate, segment-based, software virtual memory scheme, which allows it to run applications larger than available memory: code segments and resources are swapped in and thrown away when memory became scarce; data segments moved in memory when a given application had relinquished processor control.

Windows 3.x

Main articles: Windows 3.0 and Windows 3.1x

Windows 3.0, released in 1990

Windows 3.0, released in 1990, improved the design, mostly because of virtual memory and loadable virtual device drivers (VxDs) that allow Windows to share arbitrary devices between multi-tasked DOS applications.[citation needed] Windows 3.0 applications can run inprotected mode, which gives them access to several megabytes of memory without the obligation to participate in the software virtual memory scheme. They run inside the same address space, where the segmented memory provides a degree of protection. Windows 3.0 also featured improvements to the user interface. Microsoft rewrote critical operations from C into assembly. Windows 3.0 is the first Microsoft Windows version to achieve broad commercial success, selling 2 million copies in the first six months.[12][13]

Windows 3.1, made generally available on March 1, 1992, featured a facelift. In August 1993, Windows for Workgroups, a special version with integrated peer-to-peer networking features and a version number of 3.11, was released. It was sold along Windows 3.1. Support for Windows 3.1 ended on December 31, 2001.[14]

Windows 3.2, released 1994, is an updated version of the Chinese version of Windows 3.1.[15] The update was limited to this language version, as it fixed only issues related to the complex writing system of the Chinese language.[16] Windows 3.2 was generally sold by computer manufacturers with a ten-disk version of MS-DOS that also had Simplified Chinese characters in basic output and some translated utilities.

Windows 9x

Main article: Windows 9x

The next major consumer-oriented release of Windows, Windows 95, was released on August 24, 1995. While still remaining MS-DOS-based, Windows 95 introduced support for native 32-bit applications, plug and play hardware, preemptive multitasking, long file names of up to 255 characters, and provided increased stability over its predecessors. Windows 95 also introduced a redesigned, object oriented user interface, replacing the previous Program Manager with the Start menu, taskbar, and Windows Explorer shell. Windows 95 was a major commercial success for Microsoft; Ina Fried of CNET remarked that “by the time Windows 95 was finally ushered off the market in 2001, it had become a fixture on computer desktops around the world.”[17] Microsoft published four OEM Service Releases (OSR) of Windows 95, each of which was roughly equivalent to a service pack. The first OSR of Windows 95 was also the first version of Windows to be bundled with Microsoft’s web browser, Internet Explorer.[18] Mainstream support for Windows 95 ended on December 31, 2000, and extended support for Windows 95 ended on December 31, 2001.[19]

Windows 95 was followed up with the release of Windows 98 on June 25, 1998, which introduced the Windows Driver Model, support for USB composite devices, support for ACPI,hibernation, and support for multi-monitor configurations. Windows 98 also included integration with Internet Explorer 4 through Active Desktop and other aspects of the Windows Desktop Update (a series of enhancements to the Explorer shell which were also made available for Windows 95). In May 1999, Microsoft released Windows 98 Second Edition, an updated version of Windows 98. Windows 98 SE added Internet Explorer 5.0 and Windows Media Player 6.2 amongst other upgrades. Mainstream support for Windows 98 ended on June 30, 2002, and extended support for Windows 98 ended on July 11, 2006.[20]

On September 14, 2000, Microsoft released Windows ME (Millennium Edition), the last DOS-based version of Windows. Windows ME incorporated visual interface enhancements from its Windows NT-based counterpart Windows 2000, had faster boot times than previous versions (which however, required the removal of the ability to access a real modeDOS environment, removing compatibility with some older programs),[21] expanded multimedia functionality (including Windows Media Player 7, Windows Movie Maker, and theWindows Image Acquisition framework for retrieving images from scanners and digital cameras), additional system utilities such as System File Protection and System Restore, and updated home networking tools.[22] However, Windows ME was faced with criticism for its speed and instability, along with hardware compatibility issues and its removal of real mode DOS support. PC World considered Windows ME to be one of the worst operating systems Microsoft had ever released, and the 4th worst tech product of all time.[7]

Windows NT

Main article: Windows NT

Early versions

In November 1988, a new development team within Microsoft (which included former Digital Equipment Corporation developers Dave Cutler and Mark Lucovsky) began work on a revamped version of IBM and Microsoft’s OS/2 operating system known as “NT OS/2”. NT OS/2 was intended to be a secure, multi-user operating system with POSIX compatibility and a modular, portable kernel with preemptive multitasking and support for multiple processor architectures. However, following the successful release of Windows 3.0, the NT development team decided to rework the project to use an extended 32-bit port of the Windows API known as Win32 instead of those of OS/2. Win32 maintained a similar structure to the Windows APIs (allowing existing Windows applications to easily be ported to the platform), but also supported the capabilities of the existing NT kernel. Following its approval by Microsoft’s staff, development continued on what was now Windows NT, the first 32-bit version of Windows. However, IBM objected to the changes, and ultimately continued OS/2 development on its own.[23][24]

The first release of the resulting operating system, Windows NT 3.1 (named to associate it with Windows 3.1) was released in July 1993, with versions for desktop workstations andservers. Windows NT 3.5 was released in September 1994, focusing on performance improvements and support for Novell‘s NetWare, and was followed up by Windows NT 3.51 in May 1995, which included additional improvements and support for the PowerPC architecture. Windows NT 4.0 was released in June 1996, introducing the redesigned interface ofWindows 95 to the NT series. On February 17, 2000, Microsoft released Windows 2000, a successor to NT 4.0. The Windows NT name was dropped at this point in order to put a greater focus on the Windows brand.[24]

Home versions of Windows NT

The next major version of Windows NT, Windows XP, was released on October 25, 2001. The introduction of Windows XP aimed to unify the consumer-oriented Windows 9x series with the architecture introduced by Windows NT, a change which Microsoft promised would provide better performance over its DOS-based predecessors. Windows XP would also introduce a redesigned user interface (including an updated Start menu and a “task-oriented” Windows Explorer), streamlined multimedia and networking features, Internet Explorer 6, integration with Microsoft’s .NET Passport services, modes to help provide compatibility with software designed for previous versions of Windows, and Remote Assistance functionality.[25]

At retail, Windows XP was now marketed in two main editions: the “Home” edition was targeted towards consumers, while the “Professional” edition was targeted towards business environments and power users, and included additional security and networking features. Home and Professional were later accompanied by the “Media Center” edition (designed for home theater PCs, with an emphasis on support for DVD playback, TV tuner cards, DVR functionality, and remote controls), and the “Tablet PC” edition (designed for mobile devices meeting its specifications for a tablet computer, with support for stylus pen input and additional pen-enabled applications).[26][27][28] Mainstream support for Windows XP ended on April 14, 2009. Extended support ended on April 8, 2014.[29]

After Windows 2000, Microsoft also changed its release schedules for server operating systems; the server counterpart of Windows XP, Windows Server 2003, was released in April 2003.[24] It was followed in December 2005, by Windows Server 2003 R2.

Windows Vista

After a lengthy development process, Windows Vista was released on November 30, 2006, for volume licensing and January 30, 2007, for consumers. It contained a number ofnew features, from a redesigned shell and user interface to significant technical changes, with a particular focus on security features. It was available in a number of different editions, and has been subject to some criticism, such as drop of performance, longer boot time, criticism of new UAC, and stricter license agreement. Vista’s server counterpart,Windows Server 2008 was released in early 2008.

Windows 7

On July 22, 2009, Windows 7 and Windows Server 2008 R2 were released as RTM (release to manufacturing) while the former was released to the public 3 months later on October 22, 2009. Unlike its predecessor, Windows Vista, which introduced a large number of new features, Windows 7 was intended to be a more focused, incremental upgrade to the Windows line, with the goal of being compatible with applications and hardware with which Windows Vista was already compatible.[30] Windows 7 has multi-touch support, a redesigned Windows shell with an updated taskbar, a home networking system called HomeGroup,[31] and performance improvements.

Windows 8 and 8.1

Windows 8, the successor to Windows 7, was released generally on October 26, 2012. A number of significant changes were made on Windows 8, including the introduction of a user interface based around Microsoft’s Metro design language with optimizations for touch-based devices such as tablets and all-in-one PCs. These changes include the Start screen, which uses large tiles that are more convenient for touch interactions and allow for the display of continually updated information, and a new class of apps which are designed primarily for use on touch-based devices. Other changes include increased integration with cloud services and other online platforms (such as social networks and Microsoft’s own SkyDrive and Xbox Live services), the Windows Store service for software distribution, and a new variant known as Windows RT for use on devices that utilize theARM architecture.[32][33][34][35][36][37] An update to Windows 8, called Windows 8.1,[38] was released on October 17, 2013, and includes features such as new live tile sizes, deeperSkyDrive integration, and many other revisions. Windows 8 and Windows 8.1 has been subject to some criticism, such as removal of Start Menu.

Windows 10

Main article: Windows 10

On September 30, 2014, Microsoft announced Windows 10 as the successor to Windows 8.1. It was released on July 29, 2015, and addresses shortcomings in the user interface first introduced with Windows 8. Changes include the return of the Start Menu, a virtual desktop system, and the ability to run Windows Store apps within windows on the desktop rather than in full-screen mode. Windows 10 is said to be available to update from qualified Windows 7 with SP1 and Windows 8.1 computers from the Get Windows 10 Application (for Windows 7, Windows 8.1) or Windows Update (Windows 7).[39]

On November 12, 2015, an update to Windows 10, version 1511, was released.[40] This update can be activated with a Windows 7, 8 or 8.1 product key as well as Windows 10 product keys.[41] Features include new icons and right-click context menus, default printer management, four times as many tiles allowed on the Start menu, Find My Device, and Edge updates.[41]

Multilingual support

Multilingual support is built into Windows. The language for both the keyboard and the interface can be changed through the Region and Language Control Panel. Components for all supported input languages, such as Input Method Editors, are automatically installed during Windows installation (in Windows XP and earlier, files for East Asian languages, such as Chinese, and right-to-left scripts, such as Arabic, may need to be installed separately, also from the said Control Panel). Third-party IMEs may also be installed if a user feels that the provided one is insufficient for their needs.

Interface languages for the operating system are free for download, but some languages are limited to certain editions of Windows. Language Interface Packs (LIPs) are redistributable and may be downloaded from Microsoft’s Download Center and installed for any edition of Windows (XP or later) – they translate most, but not all, of the Windows interface, and require a certain base language (the language which Windows originally shipped with). This is used for most languages in emerging markets. Full Language Packs, which translates the complete operating system, are only available for specific editions of Windows (Ultimate and Enterprise editions of Windows Vista and 7, and all editions of Windows 8, 8.1 and RT except Single Language). They do not require a specific base language, and are commonly used for more popular languages such as French or Chinese. These languages cannot be downloaded through the Download Center, but available as optional updates through the Windows Update service (except Windows 8).

The interface language of installed applications are not affected by changes in the Windows interface language. Availability of languages depends on the application developers themselves.

Windows 8 and Windows Server 2012 introduces a new Language Control Panel where both the interface and input languages can be simultaneously changed, and language packs, regardless of type, can be downloaded from a central location. The PC Settings app in Windows 8.1 and Windows Server 2012 R2 also includes a counterpart settings page for this. Changing the interface language also changes the language of preinstalled Windows Store apps (such as Mail, Maps and News) and certain other Microsoft-developed apps (such as Remote Desktop). The above limitations for language packs are however still in effect, except that full language packs can be installed for any edition except Single Language, which caters to emerging markets.

Platform support

Windows NT included support for several different platforms before the x86-based personal computer became dominant in the professional world. Windows NT 4.0 and its predecessors supported PowerPC, DEC Alpha and MIPS R4000. (Although some these platforms implement 64-bit computing, the operating system treated them as 32-bit.) However, Windows 2000, the successor of Windows NT 4.0, dropped support for all platforms except the third generation x86 (known as IA-32) or newer in 32-bit mode. The client line of Window NT family still runs on IA-32, although the Windows Server line has ceased supporting this platform with the release of Windows Server 2008 R2.

With the introduction of the Intel Itanium architecture (IA-64), Microsoft released new versions of Windows to support it. Itanium versions of Windows XP and Windows Server 2003were released at the same time as their mainstream x86 counterparts. Windows XP 64-Bit Edition, released in 2005, is the last Windows client operating systems to support Itanium. Windows Server line continued to support this platform until Windows Server 2012; Windows Server 2008 R2 is the last Windows operating system to support Itanium architecture.

On April 25, 2005, Microsoft released Windows XP Professional x64 Edition and Windows Server 2003 x64 Editions to support the x86-64 (or simply x64), the eighth generation of x86 architecture. Windows Vista was the first client version of Windows NT to be released simultaneously in IA-32 and x64 editions. x64 is still supported.

An edition of Windows 8 known as Windows RT was specifically created for computers with ARM architecture and while ARM is still used for Windows smartphones with Windows 10, tablets with Windows RT will not be updated.

Windows CE

Main articles: Windows CE and Windows Phone

The latest current version of Windows CE,Windows Embedded Compact 7, displaying a concept media player UI.

Windows CE (officially known as Windows Embedded Compact), is an edition of Windows that runs on minimalistic computers, like satellite navigation systems and some mobile phones. Windows Embedded Compact is based on its own dedicated kernel, dubbed Windows CE kernel. Microsoft licenses Windows CE to OEMs and device makers. The OEMs and device makers can modify and create their own user interfaces and experiences, while Windows CE provides the technical foundation to do so.

Windows CE was used in the Dreamcast along with Sega’s own proprietary OS for the console. Windows CE was the core from whichWindows Mobile was derived. Its successor, Windows Phone 7, was based on components from both Windows CE 6.0 R3 andWindows CE 7.0. Windows Phone 8 however, is based on the same NT-kernel as Windows 8.

Windows Embedded Compact is not to be confused with Windows XP Embedded or Windows NT 4.0 Embedded, modular editions of Windows based on Windows NT kernel.

Xbox OS

Xbox OS is an unofficial name given to the version of Windows that runs on the Xbox One.[42] It is a more specific implementation with an emphasis on virtualization (using Hyper-V) as it is three operating systems running at once, consisting of the core operating system, a second implemented for games and a more Windows-like environment for applications.[43] Microsoft updates Xbox One’s OS every month, and these updates can be downloaded from the Xbox Live service to the Xbox and subsequently installed, or by using offline recovery images downloaded via a PC.[44] The Windows 10-based Core had replaced the Windows 8-based one in this update, and the new system is sometimes referred to as “Windows 10 on Xbox One” or “OneCore”.[45][46] Xbox One’s system also allows backward compatibility with Xbox 360,[47] and the Xbox 360’s system is backwards compatible with the original Xbox.[48]

Timeline of releases

The Windows family tree

Usage share

Windows logo and wordmark - 2012 (dark blue).pngMarket share overview
According to Net Applications and StatCounter data from January 2016[50][51][52][53]

Operating System Net Applications StatCounter
Windows 2000 0.01% 0.03%
Windows XP 11.42% 7.98%
Windows Server 2003 0.17%
Windows Vista 1.69% 1.77%
Windows 7 52.47% 46.66%
Windows 8 2.68% 3.15%
Windows 8.1 10.4% 11.67%
Windows 10 11.85% 13.65%
All versions 90.61% 85.18%
Operating System Net Applications StatCounter
Windows RT 8.1 0.08%
Windows Phone 7.5 0.13% 1.9%
Windows Phone 8 0.44%
Windows Phone 8.1 1.94%
Windows 10 Mobile 0.28%
All variants 2.86% 1.98%

Security

Consumer versions of Windows were originally designed for ease-of-use on a single-user PC without a network connection, and did not have security features built in from the outset.[54] However, Windows NT and its successors are designed for security (including on a network) and multi-user PCs, but were not initially designed with Internet security in mind as much, since, when it was first developed in the early 1990s, Internet use was less prevalent.[55]

These design issues combined with programming errors (e.g. buffer overflows) and the popularity of Windows means that it is a frequent target of computer worm and virus writers. In June 2005, Bruce Schneier‘s Counterpane Internet Security reported that it had seen over 1,000 new viruses and worms in the previous six months.[56] In 2005, Kaspersky Labfound around 11,000 malicious programs—viruses, Trojans, back-doors, and exploits written for Windows.[57]

Microsoft releases security patches through its Windows Update service approximately once a month (usually the second Tuesday of the month), although critical updates are made available at shorter intervals when necessary.[58] In versions of Windows after and including Windows 2000 SP3 and Windows XP, updates can be automatically downloaded and installed if the user selects to do so. As a result, Service Pack 2 for Windows XP, as well as Service Pack 1 for Windows Server 2003, were installed by users more quickly than it otherwise might have been.[59]

While the Windows 9x series offered the option of having profiles for multiple users, they had no concept of access privileges, and did not allow concurrent access; and so were not true multi-user operating systems. In addition, they implemented only partial memory protection. They were accordingly widely criticised for lack of security.

The Windows NT series of operating systems, by contrast, are true multi-user, and implement absolute memory protection. However, a lot of the advantages of being a true multi-user operating system were nullified by the fact that, prior to Windows Vista, the first user account created during the setup process was an administrator account, which was also the default for new accounts. Though Windows XP did have limited accounts, the majority of home users did not change to an account type with fewer rights – partially due to the number of programs which unnecessarily required administrator rights – and so most home users ran as administrator all the time.

Windows Vista changes this[60] by introducing a privilege elevation system called User Account Control. When logging in as a standard user, a logon session is created and atoken containing only the most basic privileges is assigned. In this way, the new logon session is incapable of making changes that would affect the entire system. When logging in as a user in the Administrators group, two separate tokens are assigned. The first token contains all privileges typically awarded to an administrator, and the second is a restricted token similar to what a standard user would receive. User applications, including the Windows Shell, are then started with the restricted token, resulting in a reduced privilege environment even under an Administrator account. When an application requests higher privileges or “Run as administrator” is clicked, UAC will prompt for confirmation and, if consent is given (including administrator credentials if the account requesting the elevation is not a member of the administrators group), start the process using the unrestricted token.[61]

File permissions

All Windows versions from Windows NT 3 have been based on a file system permission system referred to as AGLP (Accounts, Global, Local, Permissions) AGDLP which in essence where file permissions are applied to the file/folder in the form of a ‘local group’ which then has other ‘global groups’ as members. These global groups then hold other groups or users depending on different Windows versions used. This system varies from other vendor products such as Linux and NetWare due to the ‘static’ allocation of permission being applied directory to the file or folder. However using this process of AGLP/AGDLP/AGUDLP allows a small number of static permissions to be applied and allows for easy changes to the account groups without reapplying the file permissions on the files and folders.

Windows Defender

On January 6, 2005, Microsoft released a Beta version of Microsoft AntiSpyware, based upon the previously released Giant AntiSpyware. On February 14, 2006, Microsoft AntiSpyware became Windows Defender with the release of Beta 2. Windows Defender is a freeware program designed to protect against spyware and other unwanted software. Windows XP and Windows Server 2003 users who have genuine copies of Microsoft Windows can freely download the program from Microsoft’s web site, and Windows Defender ships as part of Windows Vista and 7.[62] In Windows 8, Windows Defender and Microsoft Security Essentials have been combined into a single program, named Windows Defender. It is based on Microsoft Security Essentials, borrowing its features and user interface. Although it is enabled by default, it can be turned off to use another anti-virus solution.[63] Windows Malicious Software Removal Tool and the optional Microsoft Safety Scanner are two other free security products offered by Microsoft.

Third-party analysis

In an article based on a report by Symantec,[64] internetnews.com has described Microsoft Windows as having the “fewest number of patches and the shortest average patch development time of the five operating systems it monitored in the last six months of 2006.”[65]

A study conducted by Kevin Mitnick and marketing communications firm Avantgarde in 2004, found that an unprotected and unpatched Windows XP system with Service Pack 1 lasted only 4 minutes on the Internet before it was compromised, and an unprotected and also unpatched Windows Server 2003 system was compromised after being connected to the internet for 8 hours.[66] This study does not apply to Windows XP systems running the Service Pack 2 update (released in late 2004), which vastly improved the security of Windows XP.[citation needed] The computer that was running Windows XP Service Pack 2 was not compromised. The AOL National Cyber Security Alliance Online Safety Study of October 2004, determined that 80% of Windows users were infected by at least one spyware/adware product.[citation needed] Much documentation is available describing how to increase the security of Microsoft Windows products. Typical suggestions include deploying Microsoft Windows behind a hardware or software firewall, running anti-virus and anti-spyware software, and installing patches as they become available through Windows Update.[67]

Alternative implementations

Owing to the operating system’s popularity, a number of applications have been released that aim to provide compatibility with Windows applications, either as a compatibility layerfor another operating system, or as a standalone system that can run software written for Windows out of the box. These include:

  • Wine – a free and open-source implementation of the Windows API, allowing one to run many Windows applications on x86-based platforms, including UNIX, Linux and OS X. Wine developers refer to it as a “compatibility layer”[68] and use Windows-style APIs to emulate Windows environment.
    • CrossOver – a Wine package with licensed fonts. Its developers are regular contributors to Wine, and focus on Wine running officially supported applications.
    • Cedega – proprietary fork of Wine by TransGaming Technologies, designed specifically for running Microsoft Windows games on Linux. A version of Cedega known asCider allows Windows games to run on OS X. Since Wine was licensed under the LGPL, Cedega has been unable to port the improvements made to Wine to their proprietary codebase. Cedega ceased its service in February 2011.
    • Darwine – a port of Wine for OS X and Darwin. Operates by running Wine on QEMU.
    • Linux Unified Kernel – A set of patches to the Linux kernel allowing first-class Windows executable files in Linux (using Wine DLLs) to use Windows drivers and be faster than interpreted Wine.
  • ReactOS – an open-source OS intended to run the same software as Windows, originally designed to simulate Windows NT 4.0, now aiming at Windows 7 compatibility. It has been in the development stage since 1996.
  • Linspire – formerly LindowsOS, a commercial Linux distribution initially created with the goal of running major Windows software. Changed its name to Linspire after Microsoft v. Lindows. Discontinued in favor of Xandros Desktop.
  • Freedows OS – an open-source attempt at creating a Windows clone for x86 platforms, intended to be released under the GNU General Public License. Started in 1996, by Reece K. Sellin, the project was never completed, getting only to the stage of design discussions which featured a number of novel concepts until it was suspended in 2002.[69][70][71]

See also

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  70. Jump up^ “Older blog entries for chipx86”. Advogato.org. Advogato. June 27, 2002. RetrievedMay 17, 2013.
  71. Jump up^ “Freedows splits”. Slashdot. Dice Holdings. August 31, 1998. Retrieved May 17,2013.

Telephone

A telephone, or phone, is a telecommunications device that permits two or more users to conduct a conversation when they are too far apart to be heard directly. A telephone converts sound, typically and most efficiently the human voice, into electronic signals suitable fortransmission via cables or other transmission media over long distances, and replays such signals simultaneously in audible form to its user.

In 1876, Scottish emigrant Alexander Graham Bell was the first to be granted a United States patent for a device that produced clearly intelligible replication of the human voice. This instrument was further developed by many others. The telephone was the first device in history that enabled people to talk directly with each other across large distances. Telephones rapidly became indispensable to businesses, government, and households, and are today some of the most widely used small appliances.

The essential elements of a telephone are a microphone (transmitter) to speak into and an earphone (receiver) which reproduces the voice in a distant location. In addition, most telephones contain a ringer which produces a sound to announce an incoming telephone call, and a dial or keypad used to enter a telephone number when initiating a call to another telephone. Until approximately the 1970s most telephones used a rotary dial, which was superseded by the modern DTMF push-button dial, first introduced to the public by AT&T in 1963.[1] The receiver and transmitter are usually built into a handset which is held up to the ear and mouth during conversation. The dial may be located either on the handset, or on a base unit to which the handset is connected. The transmitter converts the sound waves to electrical signalswhich are sent through the telephone network to the receiving phone. The receiving telephone converts the signals into audible sound in the receiver, or sometimes a loudspeaker. Telephones permit duplex communication, meaning they allow the people on both ends to talk simultaneously.

The first telephones were directly connected to each other from one customer’s office or residence to another customer’s location. Being impractical beyond just a few customers, these systems were quickly replaced by manually operated centrally located switchboards. This gave rise to landline telephone service in which each telephone is connected by a pair of dedicated wires to a local central office switching system, which developed into fully automated systems starting in the early 1900s. As greater mobility was desired for commerce and convenience, various radio systems were developed for transmission between mobile customer stations on ships and automobiles from the 1930s by the mid-1900s. Radio systems evolved into various cellular topologies until the first hand-held mobile phone was introduced for personal service starting in 1973 by Motorola. By the late 1970s several mobile telephone networks operated around the world. In 1983, the Advanced Mobile Phone System (AMPS) was launched in the U.S. and in other countries soon after, and offered a standardized technology providing portability for user’s within a region far beyond the personal residence or office location. These analog cellular system evolved into digital networks with better security, greater capacity, better regional coverage, and lower cost. The public switched telephone network, with its hierarchical system of many switching centers, interconnects telephones around the world for communication with each other. With the standardized international numbering system, E.164, each telephone line has an identifying telephone number, that may be called from any authorized telephone on the network.

Although originally designed for simple voice communications, convergence has enabled most modern cell phones to have many additional capabilities. They may be able torecord spoken messages, send and receive text messages, take and display photographs or video, play music or games, surf the Internet, do road navigation or immerse the user in virtual reality. Since 1999, the trend for mobile phones is smartphones that integrate all mobile communication and computing needs.

Basic principles

Schematic of a landline telephone installation.

A traditional landline telephone system, also known as plain old telephone service (POTS), commonly carries both control and audio signals on the same twisted pair (C in diagram) of insulated wires, the telephone line. The control and signaling equipment consists of three components, the ringer, the hookswitch, and a dial. The ringer, or beeper, light or other device (A7), alerts the user to incoming calls. The hookswitch signals to the central office that the user has picked up the handset to either answer a call or initiate a call. A dial, if present, is used by the subscriber to transmit a telephone number to the central office when initiating a call. Until the 1960s dials used almost exclusively the rotary technology, which was replaced by dual-tone multi-frequency signaling (DTMF) with pushbutton telephones (A4).

A major expense of wire-line telephone service is the outside wire plant. Telephones transmit both the incoming and outgoing speech signals on a single pair of wires. A twisted pair line rejects electromagnetic interference (EMI) and crosstalk better than a single wire or an untwisted pair. The strong outgoing speech signal from the microphone (transmitter) does not overpower the weaker incoming speaker (receiver) signal with sidetone because a hybrid coil (A3) and other components compensate the imbalance. The junction box (B) arrests lightning (B2) and adjusts the line’s resistance (B1) to maximize the signal power for the line length. Telephones have similar adjustments for inside line lengths (A8). The line voltages are negative compared to earth, to reduce galvanic corrosion. Negative voltage attracts positive metal ions toward the wires.

Details of operation

Further information: Telephone call

The landline telephone contains a switchhook (A4) and an alerting device, usually a ringer (A7), that remains connected to the phone line whenever the phone is “on hook” (i.e. the switch (A4) is open), and other components which are connected when the phone is “off hook“. The off-hook components include a transmitter (microphone, A2), a receiver (speaker, A1), and other circuits for dialing, filtering (A3), and amplification.

A calling party wishing to speak to another party will pick up the telephone’s handset, thereby operating a lever which closes the switchhook (A4), which powers the telephone by connecting the transmitter (microphone), receiver (speaker), and related audio components to the line. The off-hook circuitry has a low resistance (less than 300 ohms) which causes a direct current (DC), which comes down the line (C) from the telephone exchange. The exchange detects this current, attaches a digit receiver circuit to the line, and sends a dial tone to indicate readiness. On a modern push-button telephone, the caller then presses the number keys to send the telephone number of the called party. The keys control a tone generator circuit (not shown) that makes DTMF tones that the exchange receives. A rotary-dial telephone uses pulse dialing, sending electrical pulses, that the exchange can count to get the telephone number (as of 2010 many exchanges were still equipped to handle pulse dialing). If the called party’s line is available, the exchange sends an intermittent ringing signal (about 75 volts alternating current (AC) in North America and UK and 60 volts in Germany) to alert the called party to an incoming call. If the called party’s line is in use, the exchange returns a busy signal to the calling party. However, if the called party’s line is in use but has call waiting installed, the exchange sends an intermittent audible tone to the called party to indicate an incoming call.

The ringer of a telephone (A7) is connected to the line through a capacitor (A6), which blocks direct current but passes the alternating current of the ringing signal. The telephone draws no current when it is on hook, while a DC voltage is continually applied to the line. Exchange circuitry (D2) can send an AC current down the line to activate the ringer and announce an incoming call. When there is no automatic exchange, telephones have hand-cranked magnetos to generate a ringing voltage back to the exchange or any other telephone on the same line. When a landline telephone is inactive (on hook), the circuitry at the telephone exchange detects the absence of direct current to indicate that the line is not in use. When a party initiates a call to this line, the exchange sends the ringing signal. When the called party picks up the handset, they actuate a double-circuit switchhook (not shown) which may simultaneously disconnects the alerting device and connects the audio circuitry to the line. This, in turn, draws direct current through the line, confirming that the called phone is now active. The exchange circuitry turns off the ring signal, and both telephones are now active and connected through the exchange. The parties may now converse as long as both phones remain off hook. When a party hangs up, placing the handset back on the cradle or hook, direct current ceases in that line, signaling the exchange to disconnect the call.

Calls to parties beyond the local exchange are carried over trunk lines which establish connections between exchanges. In modern telephone networks, fiber-optic cable and digital technology are often employed in such connections. Satellite technology may be used for communication over very long distances.

In most landline telephones, the transmitter and receiver (microphone and speaker) are located in the handset, although in a speakerphone these components may be located in the base or in a separate enclosure. Powered by the line, the microphone (A2) produces a modulated electric current which varies its frequency and amplitude in response to thesound waves arriving at its diaphragm. The resulting current is transmitted along the telephone line to the local exchange then on to the other phone (via the local exchange or via a larger network), where it passes through the coil of the receiver (A3). The varying current in the coil produces a corresponding movement of the receiver’s diaphragm, reproducing the original sound waves present at the transmitter.

Along with the microphone and speaker, additional circuitry is incorporated to prevent the incoming speaker signal and the outgoing microphone signal from interfering with each other. This is accomplished through a hybrid coil (A3). The incoming audio signal passes through a resistor (A8) and the primary winding of the coil (A3) which passes it to the speaker (A1). Since the current path A8 – A3 has a far lower impedance than the microphone (A2), virtually all of the incoming signal passes through it and bypasses the microphone.

At the same time the DC voltage across the line causes a DC current which is split between the resistor-coil (A8-A3) branch and the microphone-coil (A2-A3) branch. The DC current through the resistor-coil branch has no effect on the incoming audio signal. But the DC current passing through the microphone is turned into AC current (in response to voice sounds) which then passes through only the upper branch of the coil’s (A3) primary winding, which has far fewer turns than the lower primary winding. This causes a small portion of the microphone output to be fed back to the speaker, while the rest of the AC current goes out through the phone line.

A lineman’s handset is a telephone designed for testing the telephone network, and may be attached directly to aerial lines and other infrastructure components.

History

Before the development of the electric telephone, the term “telephone” was applied to other inventions, and not all early researchers of the electrical device called it “telephone”. A communication device for sailing vessels The Telephone was the invention of a captain John Taylor in 1844. This instrument used four air horns to communicate with vessels in foggy weather.[2] Later, c. 1860, Johann Philipp Reis used the term in reference to his Reis telephone, his device appears to be the first such device based on conversion of sound into electrical impulses, the term telephone was adopted into the vocabulary of many languages. It is derived from the Greek: τῆλε, tēle, “far” and φωνή, phōnē, “voice”, together meaning “distant voice”.

Bell placing the first New York to Chicago telephone call in 1892

Credit for the invention of the electric telephone is frequently disputed. As with other influential inventions such as radio, television, the light bulb, and the computer, several inventors pioneered experimental work on voice transmission over a wire and improved on each other’s ideas. New controversies over the issue still arise from time to time. Charles Bourseul, Antonio Meucci, Johann Philipp Reis, Alexander Graham Bell, and Elisha Gray, amongst others, have all been credited with the invention of the telephone.[3]

Alexander Graham Bell was the first to be awarded a patent for the electric telephone by the United States Patent and Trademark Office(USPTO) in March 1876.[4] The Bell patents were forensically victorious and commercially decisive. That first patent by Bell was the master patent of the telephone, from which other patents for electric telephone devices and features flowed.[5]

In 1876, shortly after the telephone was invented, Hungarian engineer Tivadar Puskás invented the telephone switch, which allowed for the formation of telephone exchanges, and eventually networks.[6]

Early development

Reis’ telephone

1896 Telephone fromSweden

Wooden wall telephone with a hand-cranked magnetogenerator

A modern mobile phone, also called a cell phone

  • 1844 — Innocenzo Manzetti first mooted the idea of a “speaking telegraph” or telephone. Use of the ‘speaking telegraph’ and ‘sound telegraph’ monikers would eventually be replaced by the newer, distinct name, ‘telephone’.
  • 26 August 1854 — Charles Bourseul published an article in the magazine L’Illustration (Paris): “Transmission électrique de la parole” (electric transmission of speech), describing a ‘make-and-break’ type telephone transmitter later created by Johann Reis.
  • 26 October 1861 — Johann Philipp Reis (1834–1874) publicly demonstrated the Reis telephone before the Physical Society of Frankfurt. Reis’ telephone was not limited to musical sounds. Reis also used his telephone to transmit the phrase “Das Pferd frisst keinen Gurkensalat” (The horse does not eat cucumber salad).
  • 22 August 1865, La Feuille d’Aoste reported “It is rumored that English technicians to whom Mr. Manzetti illustrated his method for transmitting spoken words on the telegraph wire intend to apply said invention in England on several private telegraph lines”. However telephones would not be demonstrated there until 1876, with a set of telephones from Bell.
  • 28 December 1871 — Antonio Meucci files patent caveat No. 3335 in the U.S. Patent Office titled “Sound Telegraph”, describing communication of voice between two people by wire. A ‘patent caveat’ was not an invention patent award, but only an unverified notice filed by an individual that he or she intends to file a regular patent application in the future.
  • 1874 — Meucci, after having renewed the caveat for two years does not renew it again, and the caveat lapses.
  • 6 April 1875 — Bell’s U.S. Patent 161,739 “Transmitters and Receivers for Electric Telegraphs” is granted. This uses multiple vibrating steel reeds in make-break circuits.
  • 11 February 1876 — Gray invents a liquid transmitter for use with a telephone but does not build one.
  • 14 February 1876 — Elisha Gray files a patent caveat for transmitting the human voice through a telegraphic circuit.
  • 14 February 1876 — Alexander Bell applies for the patent “Improvements in Telegraphy”, for electromagnetic telephones using what is now called amplitude modulation (oscillating current and voltage) but which he referred to as “undulating current”.
  • 19 February 1876 — Gray is notified by the U.S. Patent Office of an interference between his caveat and Bell’s patent application. Gray decides to abandon his caveat.
  • 7 March 1876 — Bell’s U.S. patent 174,465 “Improvement in Telegraphy” is granted, covering “the method of, and apparatus for, transmitting vocal or other sounds telegraphically … by causing electrical undulations, similar in form to the vibrations of the air accompanying the said vocal or other sound.”
  • 10 March 1876 — The first successful telephone transmission of clear speech using a liquid transmitter when Bell spoke into his device, “Mr. Watson, come here, I want to see you.” and Watson heard each word distinctly.
  • 30 January 1877 — Bell’s U.S. patent 186,787 is granted for an electromagnetic telephone using permanent magnets, iron diaphragms, and a call bell.
  • 27 April 1877 — Edison files for a patent on a carbon (graphite) transmitter. The patent 474,230 was granted 3 May 1892, after a 15-year delay because of litigation. Edison was granted patent 222,390 for a carbon granules transmitter in 1879.

Early commercial instruments

Early telephones were technically diverse. Some used a liquid transmitter, some had a metal diaphragm that induced current in an electromagnet wound around a permanent magnet, and some were “dynamic” – their diaphragm vibrated a coil of wire in the field of a permanent magnet or the coil vibrated the diaphragm. The sound-powered dynamic kind survived in small numbers through the 20th century in military and maritime applications, where its ability to create its own electrical power was crucial. Most, however, used the Edison/Berliner carbon transmitter, which was much louder than the other kinds, even though it required an induction coil which was an impedance matching transformer to make it compatible with the impedance of the line. The Edison patents kept the Bell monopoly viable into the 20th century, by which time the network was more important than the instrument.

Early telephones were locally powered, using either a dynamic transmitter or by the powering of a transmitter with a local battery. One of the jobs ofoutside plant personnel was to visit each telephone periodically to inspect the battery. During the 20th century, “common battery” operation came to dominate, powered by “talk battery” from the telephone exchange over the same wires that carried the voice signals.

Early telephones used a single wire for the subscriber’s line, with ground return used to complete the circuit (as used in telegraphs). The earliest dynamic telephones also had only one port opening for sound, with the user alternately listening and speaking (or rather, shouting) into the same hole. Sometimes the instruments were operated in pairs at each end, making conversation more convenient but also more expensive.

Acoustic telephone ad, The Consolidated Telephone Co., Jersey City, NJ 1886

At first, the benefits of a telephone exchange were not exploited. Instead telephones were leased in pairs to a subscriber, who had to arrange for a telegraph contractor to construct a line between them, for example between a home and a shop. Users who wanted the ability to speak to several different locations would need to obtain and set up three or four pairs of telephones. Western Union, already using telegraph exchanges, quickly extended the principle to its telephones in New York City and San Francisco, and Bell was not slow in appreciating the potential.

Signalling began in an appropriately primitive manner. The user alerted the other end, or the exchange operator, by whistling into the transmitter. Exchange operation soon resulted in telephones being equipped with a bell in a ringer box, first operated over a second wire, and later over the same wire, but with a condenser (capacitor) in series with the bell coil to allow the AC ringer signal through while still blocking DC (keeping the phone “on hook“). Telephones connected to the earliest Strowger automatic exchanges had seven wires, one for the knife switch, one for eachtelegraph key, one for the bell, one for the push-button and two for speaking. Large wall telephones in the early 20th century usually incorporated the bell, and separate bell boxes for desk phones dwindled away in the middle of the century.

Rural and other telephones that were not on a common battery exchange had a magneto hand-cranked generator to produce a high voltage alternating signal to ring the bells of other telephones on the line and to alert the operator. Some local farming communities that were not connected to the main networks set up barbed wire telephone lines that exploited the existing system of field fences to transmit the signal.

In the 1890s a new smaller style of telephone was introduced, packaged in three parts. The transmitter stood on a stand, known as a “candlestick” for its shape. When not in use, the receiver hung on a hook with a switch in it, known as a “switchhook.” Previous telephones required the user to operate a separate switch to connect either the voice or the bell. With the new kind, the user was less likely to leave the phone “off the hook”. In phones connected to magneto exchanges, the bell, induction coil, battery and magneto were in a separate bell box or “ringer box“.[7] In phones connected to common battery exchanges, the ringer box was installed under a desk, or other out of the way place, since it did not need a battery or magneto.

Cradle designs were also used at this time, having a handle with the receiver and transmitter attached, now called a handset, separate from the cradle base that housed the magneto crank and other parts. They were larger than the “candlestick” and more popular.

Ericsson DBH 1001 (ca. 1931), the first combined telephone made with a Bakelite housing and handset.

File:Oldphone.ogg

This video shows the operation of an old phone (Ericsson LM)

Telephone used by American soldiers (WWII, Minalin, Pampanga,Philippines)

Disadvantages of single wire operation such as crosstalk and hum from nearby AC power wires had already led to the use of twisted pairs and, for long distance telephones, four-wire circuits. Users at the beginning of the 20th century did not place long distance calls from their own telephones but made an appointment to use a special sound-proofed long distance telephone booth furnished with the latest technology.

What turned out to be the most popular and longest lasting physical style of telephone was introduced in the early 20th century, including Bell’s 202-type desk set. A carbon granule transmitter and electromagnetic receiver were united in a single molded plastic handle, which when not in use sat in a cradle in the base unit. The circuit diagram of the model 202 shows the direct connection of the transmitter to the line, while the receiver was induction coupled. In local battery configurations, when the local loop was too long to provide sufficient current from the exchange, the transmitter was powered by a local battery and inductively coupled, while the receiver was included in the local loop.[8] The coupling transformer and the ringer were mounted in a separate enclosure, called the subscriber set. The dial switch in the base interrupted the line current by repeatedly but very briefly disconnecting the line 1 to 10 times for each digit, and the hook switch (in the center of the circuit diagram) disconnected the line and the transmitter battery while the handset was on the cradle.

In the 1930s, telephone sets were developed that combined the bell and induction coil with the desk set, obviating a separate ringer box. The rotary dial becoming common-place in the 1930s in many areas enabled customer-dialed service, but some magneto systems remained even into the 1960s. After World-War II, the telephone networks saw rapid expansion and more efficient telephone sets, such as the model 500 telephone in the United States, were developed that permitted larger local networks centered around central offices. A break-through new technology was the introduction of Touch-Tone signaling using push-button telephones by American Telephone & Telegraph Company (AT&T) in 1963.

Digital telephones and voice over IP

The invention of the transistor in 1947 dramatically changed the technology used in telephone systems and in the long-distance transmission networks. With the development of electronic switching systems in the 1960s, telephony gradually evolved towards digital telephony which improved the capacity, quality, and cost of the network.

The development of digital data communications method, such as the protocols used for the Internet, it became possible to digitize voice and transmit it as real-time data across computer networks, giving rise to the field of Internet Protocol (IP) telephony, also known as voice over Internet Protocol (VoIP), a term that reflects the methodology memorably. VoIP has proven to be a disruptive technology that is rapidly replacing traditional telephone network infrastructure.

As of January 2005, up to 10% of telephone subscribers in Japan and South Korea have switched to this digital telephone service. A January 2005 Newsweek article suggested that Internet telephony may be “the next big thing.”[9] As of 2006 many VoIP companies offer service to consumers and businesses.

An IP desktop telephone attached to a computer network, with touch-tone dialing

From a customer perspective, IP telephony uses a high-bandwidth Internet connection and specialized customer premises equipment to transmit telephone calls via the Internet, or any modern private data network. The customer equipment may be an analog telephone adapter (ATA) which interfaces a conventional analog telephone to the IP networking equipment, or it may be an IP Phone that has the networking and interface technology built into the desk-top set and provides the traditional, familiar parts of a telephone, the handset, the dial or keypad, and a ringer in a package that usually resembles a standard telephone set.

In addition, many computer software vendors and telephony operators provide softphone application software that emulates a telephone by use of an attached microphone and audio headset, or loud speaker.

Despite the new features and conveniences of IP telephones, some may have notable disadvantages compared to traditional telephones. Unless the IP telephone’s components are backed up with an uninterruptible power supply or other emergency power source, the phone ceases to function during a power outage as can occur during an emergency or disaster when the phone is most needed. Traditional phones connected to the older PSTN network do not experience that problem since they are powered by the telephone company’s battery supply, which will continue to function even if there is a prolonged power outage. Another problem in Internet-based services is the lack of a fixed physical location, impacting the provisioning of emergency services such as police, fire or ambulance, should someone call for them. Unless the registered user updates the IP phone’s physical address location after moving to a new residence, emergency services can be, and have been, dispatched to the wrong location.

Fixed telephone lines per 100 inhabitants 1997–2007

Symbols

Graphic symbols used to designate telephone service or phone-related information in print, signage, and other media include (U+2121), (U+260E), (U+260F), (U+2706), and (U+2315).

Use

By the end of 2009, there were a total of nearly 6 billion mobile and fixed-line telephone subscribers worldwide. This included 1.26 billion fixed-line subscribers and 4.6 billion mobile subscribers.[10]

Patents

  • US 174,465Telegraphy (Bell’s first telephone patent) — Alexander Graham Bell
  • US 186,787Electric Telegraphy (permanent magnet receiver) — Alexander Graham Bell
  • US 474,230Speaking Telegraph (graphite transmitter) — Thomas Edison
  • US 203,016Speaking Telephone (carbon button transmitter) — Thomas Edison
  • US 222,390Carbon Telephone (carbon granules transmitter) — Thomas Edison
  • US 485,311Telephone (solid back carbon transmitter) — Anthony C. White (Bell engineer) This design was used until 1925 and installed phones were used until the 1940s.
  • US 3,449,750Duplex Radio Communication and Signalling Appartus—G. H. Sweigert
  • US 3,663,762Cellular Mobile Communication System—Amos Edward Joel (Bell Labs)
  • US 3,906,166Radio Telephone System (DynaTAC cell phone) — Martin Cooper et al. (Motorola)

Bluetooth

Bluetooth is a wireless technology standard for exchanging data over short distances (using short-wavelength UHF radio waves in the ISM band from 2.4 to 2.485 GHz[4]) from fixed and mobile devices, and building personal area networks (PANs). Invented by telecom vendor Ericsson in 1994,[5] it was originally conceived as a wireless alternative to RS-232 data cables. It can connect several devices, overcoming problems of synchronization.

Bluetooth is managed by the Bluetooth Special Interest Group (SIG), which has more than 25,000 member companies in the areas of telecommunication, computing, networking, and consumer electronics.[6] The IEEE standardized Bluetooth as IEEE 802.15.1, but no longer maintains the standard. The Bluetooth SIG oversees development of the specification, manages the qualification program, and protects the trademarks.[7] A manufacturer must make a device meet Bluetooth SIG standards to market it as a Bluetooth device.[8] A network of patents apply to the technology, which are licensed to individual qualifying devices.

[edit]

The name “Bluetooth” is an Anglicised version of the Scandinavian Blåtand/Blåtann (Old Norse blátǫnn), the epithet of the tenth-century king Harald Bluetooth who united dissonant Danish tribes into a single kingdom and, according to legend, introduced Christianity as well. The idea of this name was proposed in 1997 by Jim Kardach who developed a system that would allow mobile phones to communicate with computers. At the time of this proposal he was reading Frans G. Bengtsson‘s historical novel The Long Ships about Vikings and King Harald Bluetooth.[9][10] The implication is that Bluetooth does the same with communications protocols, uniting them into one universal standard.[11]

The Bluetooth logo is a bind rune merging the Younger Futhark runes Runic letter ior.svg (Hagall) (ᚼ) and Runic letter berkanan.svg (Bjarkan) (ᛒ), Harald’s initials.

Implementation[edit]

Bluetooth operates at frequencies between 2402 and 2480 MHz, or 2400 and 2483.5 MHz including guard bands 2 MHz wide at the bottom end and 3.5 MHz wide at the top.[12]This is in the globally unlicensed (but not unregulated) Industrial, Scientific and Medical (ISM) 2.4 GHz short-range radio frequency band. Bluetooth uses a radio technology calledfrequency-hopping spread spectrum. Bluetooth divides transmitted data into packets, and transmits each packet on one of 79 designated Bluetooth channels. Each channel has a bandwidth of 1 MHz. It usually performs 1600 hops per second, with Adaptive Frequency-Hopping (AFH) enabled.[12] Bluetooth low energy uses 2 MHz spacing, which accommodates 40 channels.

Originally, Gaussian frequency-shift keying (GFSK) modulation was the only modulation scheme available. Since the introduction of Bluetooth 2.0+EDR, π/4-DQPSK (Differential Quadrature Phase Shift Keying) and 8DPSK modulation may also be used between compatible devices. Devices functioning with GFSK are said to be operating in basic rate (BR) mode where an instantaneous data rate of 1 Mbit/s is possible. The term Enhanced Data Rate (EDR) is used to describe π/4-DPSK and 8DPSK schemes, each giving 2 and 3 Mbit/s respectively. The combination of these (BR and EDR) modes in Bluetooth radio technology is classified as a “BR/EDR radio”.

Bluetooth is a packet-based protocol with a master-slave structure. One master may communicate with up to seven slaves in a piconet. All devices share the master’s clock. Packet exchange is based on the basic clock, defined by the master, which ticks at 312.5 µs intervals. Two clock ticks make up a slot of 625 µs, and two slots make up a slot pair of 1250 µs. In the simple case of single-slot packets the master transmits in even slots and receives in odd slots. The slave, conversely, receives in even slots and transmits in odd slots. Packets may be 1, 3 or 5 slots long, but in all cases the master’s transmission begins in even slots and the slave’s in odd slots.

The above is valid for “classic” BT. Bluetooth Low Energy, introduced in the 4.0 specification, uses the same spectrum but somewhat differently; see Bluetooth low energy#Radio interface.

Communication and connection[edit]

A master Bluetooth device can communicate with a maximum of seven devices in a piconet (an ad-hoc computer network using Bluetooth technology), though not all devices reach this maximum. The devices can switch roles, by agreement, and the slave can become the master (for example, a headset initiating a connection to a phone necessarily begins as master—as initiator of the connection—but may subsequently operate as slave).

The Bluetooth Core Specification provides for the connection of two or more piconets to form a scatternet, in which certain devices simultaneously play the master role in one piconet and the slave role in another.

At any given time, data can be transferred between the master and one other device (except for the little-used broadcast mode.[citation needed]) The master chooses which slave device to address; typically, it switches rapidly from one device to another in a round-robin fashion. Since it is the master that chooses which slave to address, whereas a slave is (in theory) supposed to listen in each receive slot, being a master is a lighter burden than being a slave. Being a master of seven slaves is possible; being a slave of more than one master is difficult.[citation needed] The specification is vague as to required behavior in scatternets.

Many USB Bluetooth adapters or “dongles” are available, some of which also include an IrDA adapter.[citation needed]

Uses[edit]

Class Max. permitted power Typ. range[3]
(m)
(mW) (dBm)
1 100 20 ~100
2 2.5 4 ~10
3 1 0 ~1

Bluetooth is a standard wire-replacement communications protocol primarily designed for low-power consumption, with a short range based on low-cost transceiver microchips in each device.[13] Because the devices use a radio (broadcast) communications system, they do not have to be in visual line of sight of each other, however a quasi optical wireless path must be viable.[6] Range is power-class-dependent, but effective ranges vary in practice; see the table on the right.

Officially Class 3 radios have a range of up to 1 metre (3 ft), Class 2, most commonly found in mobile devices, 10 metres (33 ft), and Class 1, primarily for industrial use cases,100 metres (300 ft).[3] Bluetooth Marketing qualifies that Class 1 range is in most cases 20–30 metres (66–98 ft), and Class 2 range 5–10 metres (16–33 ft).[2]

Version Data rate Max. application throughput
1.2 Mbit/s >80 kbit/s
2.0 + EDR 3 Mbit/s >80 kbit/s
3.0 + HS 24 Mbit/s See Version 3.0 + HS
4.0 24 Mbit/s See Version 4.0 LE

The effective range varies due to propagation conditions, material coverage, production sample variations, antenna configurations and battery conditions. Most Bluetooth applications are for indoor conditions, where attenuation of walls and signal fading due to signal reflections make the range far lower than specified line-of-sight ranges of the Bluetooth products. Most Bluetooth applications are battery powered Class 2 devices, with little difference in range whether the other end of the link is a Class 1 or Class 2 device as the lower powered device tends to set the range limit. In some cases the effective range of the data link can be extended when a Class 2 device is connecting to a Class 1 transceiver with both higher sensitivity and transmission power than a typical Class 2 device.[14] Mostly however the Class 1 devices have a similar sensitivity to Class 2 devices. Connecting two Class 1 devices with both high sensitivity and high power can allow ranges far in excess of the typical 100m, depending on the throughput required by the application. Some such devices allow open field ranges of up to 1 km and beyond between two similar devices without exceeding legal emission limits.[15][16][17]

The Bluetooth Core Specification mandates a range of not less than 10 metres (33 ft), but there is no upper limit on actual range. Manufacturers’ implementations can be tuned to provide the range needed for each case.[3]

Bluetooth profiles[edit]

Main article: Bluetooth profile

To use Bluetooth wireless technology, a device must be able to interpret certain Bluetooth profiles, which are definitions of possible applications and specify general behaviours that Bluetooth-enabled devices use to communicate with other Bluetooth devices. These profiles include settings to parametrize and to control the communication from start. Adherence to profiles saves the time for transmitting the parameters anew before the bi-directional link becomes effective. There are a wide range of Bluetooth profiles that describe many different types of applications or use cases for devices.[18][19]

List of applications[edit]

A typical Bluetooth mobile phoneheadset.

  • Wireless control of and communication between a mobile phone and a handsfree headset. This was one of the earliest applications to become popular.[20]
  • Wireless control of and communication between a mobile phone and a Bluetooth compatible car stereo system.
  • Wireless control of and communication with tablets and speakers such as iOS and Android devices.
  • Wireless Bluetooth headset and Intercom. Idiomatically, a headset is sometimes called “a Bluetooth”.
  • Wireless streaming of audio to headphones with or without communication capabilities.
  • Wireless networking between PCs in a confined space and where little bandwidth is required.[21]
  • Wireless communication with PC input and output devices, the most common being the mouse, keyboard and printer.
  • Transfer of files, contact details, calendar appointments, and reminders between devices with OBEX.
  • Replacement of previous wired RS-232 serial communications in test equipment, GPS receivers, medical equipment, bar code scanners, and traffic control devices.
  • For controls where infrared was often used.
  • For low bandwidth applications where higher USB bandwidth is not required and cable-free connection desired.
  • Sending small advertisements from Bluetooth-enabled advertising hoardings to other, discoverable, Bluetooth devices.[22]
  • Wireless bridge between two Industrial Ethernet (e.g., PROFINET) networks.
  • Three seventh and eighth generation game consoles, Nintendo‘s Wii.[23] and Sony‘s PlayStation 3, use Bluetooth for their respective wireless controllers.
  • Dial-up internet access on personal computers or PDAs using a data-capable mobile phone as a wireless modem.
  • Short range transmission of health sensor data from medical devices to mobile phone, set-top box or dedicated telehealth devices.[24]
  • Allowing a DECT phone to ring and answer calls on behalf of a nearby mobile phone.
  • Real-time location systems (RTLS), are used to track and identify the location of objects in real-time using “Nodes” or “tags” attached to, or embedded in the objects tracked, and “Readers” that receive and process the wireless signals from these tags to determine their locations.[25]
  • Personal security application on mobile phones for prevention of theft or loss of items. The protected item has a Bluetooth marker (e.g., a tag) that is in constant communication with the phone. If the connection is broken (the marker is out of range of the phone) then an alarm is raised. This can also be used as a man overboard alarm. A product using this technology has been available since 2009.[26]
  • Calgary, Alberta, Canada‘s Roads Traffic division uses data collected from travelers’ Bluetooth devices to predict travel times and road congestion for motorists.[27]
  • Wireless transmission of audio,[28] (a more reliable alternative to FM transmitters)

Bluetooth vs. Wi-Fi (IEEE 802.11)[edit]

Bluetooth and Wi-Fi (the brand name for products using IEEE 802.11 standards) have some similar applications: setting up networks, printing, or transferring files. Wi-Fi is intended as a replacement for high speed cabling for general local area network access in work areas. This category of applications is sometimes called wireless local area networks (WLAN). Bluetooth was intended for portable equipment and its applications. The category of applications is outlined as the wireless personal area network (WPAN). Bluetooth is a replacement for cabling in a variety of personally carried applications in any setting, and also works for fixed location applications such as smart energy functionality in the home (thermostats, etc.).

Wi-Fi and Bluetooth are to some extent complementary in their applications and usage. Wi-Fi is usually access point-centered, with an asymmetrical client-server connection with all traffic routed through the access point, while Bluetooth is usually symmetrical, between two Bluetooth devices. Bluetooth serves well in simple applications where two devices need to connect with minimal configuration like a button press, as in headsets and remote controls, while Wi-Fi suits better in applications where some degree of client configuration is possible and high speeds are required, especially for network access through an access node. However, Bluetooth access points do exist and ad-hoc connections are possible with Wi-Fi though not as simply as with Bluetooth. Wi-Fi Direct was recently developed to add a more Bluetooth-like ad-hoc functionality to Wi-Fi.[citation needed]

Devices[edit]

A Bluetooth USB dongle with a 100 m range.

Bluetooth exists in many products, such as telephones, tablets, media players, robotics systems, handheld, laptops and console gaming equipment, and some high definition headsets, modems, and watches.[29] The technology is useful when transferring information between two or more devices that are near each other in low-bandwidth situations. Bluetooth is commonly used to transfer sound data with telephones (i.e., with a Bluetooth headset) or byte data with hand-held computers (transferring files).

Bluetooth protocols simplify the discovery and setup of services between devices.[30] Bluetooth devices can advertise all of the services they provide.[31] This makes using services easier, because more of the security, network address and permission configuration can be automated than with many other network types.[30]

Computer requirements[edit]

A typical Bluetooth USB dongle.

An internal notebook Bluetooth card (14×36×4 mm).

A personal computer that does not have embedded Bluetooth can use a Bluetooth adapter that enables the PC to communicate with Bluetooth devices. While some desktop computers and most recent laptops come with a built-in Bluetooth radio, others require an external adapter, typically in the form of a small USB “dongle.”

Unlike its predecessor, IrDA, which requires a separate adapter for each device, Bluetooth lets multiple devices communicate with a computer over a single adapter.[32]

Operating system implementation[edit]

For more details on this topic, see Bluetooth stack.

Apple products have worked with Bluetooth since Mac OS X v10.2, which was released in 2002.[33]

For Microsoft platforms, Windows XP Service Pack 2 and SP3 releases work natively with Bluetooth v1.1, v2.0 and v2.0+EDR.[34]Previous versions required users to install their Bluetooth adapter’s own drivers, which were not directly supported by Microsoft.[35]Microsoft’s own Bluetooth dongles (packaged with their Bluetooth computer devices) have no external drivers and thus require at least Windows XP Service Pack 2. Windows Vista RTM/SP1 with the Feature Pack for Wireless or Windows Vista SP2 work with Bluetooth v2.1+EDR.[34] Windows 7 works with Bluetooth v2.1+EDR and Extended Inquiry Response (EIR).[34]

The Windows XP and Windows Vista/Windows 7 Bluetooth stacks support the following Bluetooth profiles natively: PAN, SPP, DUN, HID, HCRP. The Windows XP stack can be replaced by a third party stack that supports more profiles or newer Bluetooth versions. The Windows Vista/Windows 7 Bluetooth stack supports vendor-supplied additional profiles without requiring that the Microsoft stack be replaced.[34]

Linux has two popular Bluetooth stacks, BlueZ and Affix. The BlueZ stack is included with most Linux kernels and was originally developed by Qualcomm.[36] The Affix stack was developed by Nokia. FreeBSD features Bluetooth since its v5.0 release. NetBSDfeatures Bluetooth since its v4.0 release. Its Bluetooth stack has been ported to OpenBSD as well.

Specifications and features[edit]

The development of the short link radio technology, later named Bluetooth, was initiated by Nils Rydbeck CTO at Ericsson Mobile in Lund. The purpose was to create a wireless headset, according to two inventions, presented in 1989, SE 8902098-6, issued 1989-06-12 and 1992 SE 9202239, issued 1992-07-24 by Dr. Johan Ullman. Nils Rydbeck tasked Tord Wingren with specifying and Jaap Haartsen and Sven Mattisson with developing, who were working for Ericsson in Lund, Sweden.[37] The specification is based onfrequency-hopping spread spectrum technology.

The specifications were formalized by the Bluetooth Special Interest Group (SIG). The SIG was formally announced on 20 May 1998. Today it has a membership of over 20,000 companies worldwide.[38] It was established by Ericsson, IBM, Intel, Toshiba and Nokia, and later joined by many other companies.

All versions of the Bluetooth standards support downward compatibility.[clarification needed] That lets the latest standard cover all older versions.

The Bluetooth Core Specification Working Group (CSWG) produces mainly 4 kinds of specifications

  • The Bluetooth Core Specification, release cycle is typically a few years in between
  • Core Specification Addendum (CSA), release cycle can be as tight as a few times per year
  • Core Specification Supplements (CSS), can be released very quickly
  • Errata

Bluetooth v1.0 and v1.0B[edit]

Versions 1.0 and 1.0B[citation needed] had many problems and manufacturers had difficulty making their products interoperable. Versions 1.0 and 1.0B also included mandatory Bluetooth hardware device address (BD_ADDR) transmission in the Connecting process (rendering anonymity impossible at the protocol level), which was a major setback for certain services planned for use in Bluetooth environments.

Bluetooth v1.1[edit]

  • Ratified as IEEE Standard 802.15.1–2002[39]
  • Many errors found in the v1.0B specifications were fixed.
  • Added possibility of non-encrypted channels.
  • Received Signal Strength Indicator (RSSI).

Bluetooth v1.2[edit]

Major enhancements include the following:

  • Faster Connection and Discovery
  • Adaptive frequency-hopping spread spectrum (AFH), which improves resistance to radio frequency interference by avoiding the use of crowded frequencies in the hopping sequence.
  • Higher transmission speeds in practice, up to 721 kbit/s,[40] than in v1.1.
  • Extended Synchronous Connections (eSCO), which improve voice quality of audio links by allowing retransmissions of corrupted packets, and may optionally increase audio latency to provide better concurrent data transfer.
  • Host Controller Interface (HCI) operation with three-wire UART.
  • Ratified as IEEE Standard 802.15.1–2005[41]
  • Introduced Flow Control and Retransmission Modes for L2CAP.

Bluetooth v2.0 + EDR[edit]

This version of the Bluetooth Core Specification was released in 2004. The main difference is the introduction of an Enhanced Data Rate (EDR) for faster data transfer. The nominal rate of EDR is about 3 Mbit/s, although the practical data transfer rate is 2.1 Mbit/s.[40] EDR uses a combination of GFSK and Phase Shift Keying modulation (PSK) with two variants, π/4-DQPSK and 8DPSK.[42] EDR can provide a lower power consumption through a reduced duty cycle.

The specification is published as Bluetooth v2.0 + EDR, which implies that EDR is an optional feature. Aside from EDR, the v2.0 specification contains other minor improvements, and products may claim compliance to “Bluetooth v2.0” without supporting the higher data rate. At least one commercial device states “Bluetooth v2.0 without EDR” on its data sheet.[43]

Bluetooth v2.1 + EDR[edit]

Bluetooth Core Specification Version 2.1 + EDR was adopted by the Bluetooth SIG on 26 July 2007.[42]

The headline feature of v2.1 is secure simple pairing (SSP): this improves the pairing experience for Bluetooth devices, while increasing the use and strength of security. See the section on Pairing below for more details.[44]

Version 2.1 allows various other improvements, including “Extended inquiry response” (EIR), which provides more information during the inquiry procedure to allow better filtering of devices before connection; and sniff subrating, which reduces the power consumption in low-power mode.

Bluetooth v3.0 + HS[edit]

Version 3.0 + HS of the Bluetooth Core Specification[42] was adopted by the Bluetooth SIG on 21 April 2009. Bluetooth v3.0 + HS provides theoretical data transfer speeds of up to24 Mbit/s, though not over the Bluetooth link itself. Instead, the Bluetooth link is used for negotiation and establishment, and the high data rate traffic is carried over a colocated802.11 link.

The main new feature is AMP (Alternative MAC/PHY), the addition of 802.11 as a high speed transport. The High-Speed part of the specification is not mandatory, and hence only devices that display the “+HS” logo actually support Bluetooth over 802.11 high-speed data transfer. A Bluetooth v3.0 device without the “+HS” suffix is only required to support features introduced in Core Specification Version 3.0[45] or earlier Core Specification Addendum 1.[46]

L2CAP Enhanced modes
Enhanced Retransmission Mode (ERTM) implements reliable L2CAP channel, while Streaming Mode (SM) implements unreliable channel with no retransmission or flow control. Introduced in Core Specification Addendum 1.
Alternative MAC/PHY
Enables the use of alternative MAC and PHYs for transporting Bluetooth profile data. The Bluetooth radio is still used for device discovery, initial connection and profile configuration. However, when large quantities of data must be sent, the high speed alternative MAC PHY 802.11 (typically associated with Wi-Fi) transports the data. This means that Bluetooth uses proven low power connection models when the system is idle, and the faster radio when it must send large quantities of data. AMP links require enhanced L2CAP modes.
Unicast Connectionless Data
Permits sending service data without establishing an explicit L2CAP channel. It is intended for use by applications that require low latency between user action and reconnection/transmission of data. This is only appropriate for small amounts of data.
Enhanced Power Control
Updates the power control feature to remove the open loop power control, and also to clarify ambiguities in power control introduced by the new modulation schemes added for EDR. Enhanced power control removes the ambiguities by specifying the behaviour that is expected. The feature also adds closed loop power control, meaning RSSI filtering can start as the response is received. Additionally, a “go straight to maximum power” request has been introduced. This is expected to deal with the headset link loss issue typically observed when a user puts their phone into a pocket on the opposite side to the headset.

Ultra-wideband[edit]

The high speed (AMP) feature of Bluetooth v3.0 was originally intended for UWB, but the WiMedia Alliance, the body responsible for the flavor of UWB intended for Bluetooth, announced in March 2009 that it was disbanding, and ultimately UWB was omitted from the Core v3.0 specification.[47]

On 16 March 2009, the WiMedia Alliance announced it was entering into technology transfer agreements for the WiMedia Ultra-wideband (UWB) specifications. WiMedia has transferred all current and future specifications, including work on future high speed and power optimized implementations, to the Bluetooth Special Interest Group (SIG), Wireless USB Promoter Group and the USB Implementers Forum. After successful completion of the technology transfer, marketing, and related administrative items, the WiMedia Alliance ceased operations.[48][49][50][51][52][53]

In October 2009 the Bluetooth Special Interest Group suspended development of UWB as part of the alternative MAC/PHY, Bluetooth v3.0 + HS solution. A small, but significant, number of former WiMedia members had not and would not sign up to the necessary agreements for the IP transfer. The Bluetooth SIG is now in the process of evaluating other options for its longer term roadmap.[54][55][56]

Bluetooth v4.0[edit]

The Bluetooth SIG completed the Bluetooth Core Specification version 4.0 (called Bluetooth Smart) and has been adopted as of 30 June 2010. It includes Classic Bluetooth,Bluetooth high speed and Bluetooth low energy protocols. Bluetooth high speed is based on Wi-Fi, and Classic Bluetooth consists of legacy Bluetooth protocols.

Bluetooth low energy, previously known as Wibree,[57] is a subset of Bluetooth v4.0 with an entirely new protocol stack for rapid build-up of simple links. As an alternative to the Bluetooth standard protocols that were introduced in Bluetooth v1.0 to v3.0, it is aimed at very low power applications running off a coin cell. Chip designs allow for two types of implementation, dual-mode, single-mode and enhanced past versions.[58] The provisional names Wibree and Bluetooth ULP (Ultra Low Power) were abandoned and the BLE name was used for a while. In late 2011, new logos “Bluetooth Smart Ready” for hosts and “Bluetooth Smart” for sensors were introduced as the general-public face of BLE.[59]

  • In a single-mode implementation, only the low energy protocol stack is implemented. STMicroelectronics,[60] AMICCOM,[61] CSR,[62] Nordic Semiconductor[63] and Texas Instruments[64] have released single mode Bluetooth low energy solutions.
  • In a dual-mode implementation, Bluetooth Smart functionality is integrated into an existing Classic Bluetooth controller. As of March 2011, the following semiconductor companies have announced the availability of chips meeting the standard: Qualcomm-Atheros, CSR, Broadcom[65][66] and Texas Instruments. The compliant architecture shares all of Classic Bluetooth’s existing radio and functionality resulting in a negligible cost increase compared to Classic Bluetooth.

Cost-reduced single-mode chips, which enable highly integrated and compact devices, feature a lightweight Link Layer providing ultra-low power idle mode operation, simple device discovery, and reliable point-to-multipoint data transfer with advanced power-save and secure encrypted connections at the lowest possible cost.

General improvements in version 4.0 include the changes necessary to facilitate BLE modes, as well the Generic Attribute Profile (GATT) and Security Manager (SM) services withAES Encryption.

Core Specification Addendum 2 was unveiled in December 2011; it contains improvements to the audio Host Controller Interface and to the High Speed (802.11) Protocol Adaptation Layer.

Core Specification Addendum 3 revision 2 has an adoption date of 24 July 2012.

Core Specification Addendum 4 has an adoption date of 12 February 2013.

Bluetooth v4.1[edit]

The Bluetooth SIG announced formal adoption of the Bluetooth v4.1 specification on 4 December 2013. This specification is an incremental software update to Bluetooth Specification v4.0, and not a hardware update. The update incorporates Bluetooth Core Specification Addenda (CSA 1, 2, 3 & 4) and adds new features that improve consumer usability. These include increased co-existence support for LTE, bulk data exchange rates—and aid developer innovation by allowing devices to support multiple roles simultaneously.[67]

New features of this specification include:

  • Mobile Wireless Service Coexistence Signaling
  • Train Nudging and Generalized Interlaced Scanning
  • Low Duty Cycle Directed Advertising
  • L2CAP Connection Oriented and Dedicated Channels with Credit Based Flow Control
  • Dual Mode and Topology
  • LE Link Layer Topology
  • 802.11n PAL
  • Audio Architecture Updates for Wide Band Speech
  • Fast Data Advertising Interval
  • Limited Discovery Time[68]

Notice that some features were already available in a Core Specification Addendum (CSA) before the release of v4.1.

Bluetooth v4.2[edit]

Bluetooth v4.2 was released on December 2, 2014. It Introduces some key features for IoT. Some features, such as Data Length Extension, require a hardware update.[69] But some older Bluetooth hardware may receive some Bluetooth v4.2 features, such as privacy updates via firmware.[70]

The major areas of improvement are:

  • LE Data Packet Length Extension
  • LE Secure Connections
  • Link Layer Privacy
  • Link Layer Extended Scanner Filter Policies
  • IP connectivity for Bluetooth Smart devices to become available soon after the introduction of BT v4.2 via the new Internet Protocol Support Profile (IPSP).
  • IPSP adds an IPv6 connection option for Bluetooth Smart, to support connected home and other IoT implementations.

Technical information[edit]

Bluetooth protocol stack[edit]

Bluetooth Protocol Stack

Bluetooth is defined as a layer protocol architecture consisting of core protocols, cable replacement protocols, telephony control protocols, and adopted protocols.[71] Mandatory protocols for all Bluetooth stacks are: LMP, L2CAP and SDP. In addition, devices that communicate with Bluetooth almost universally can use these protocols: HCI and RFCOMM.[citation needed]

LMP[edit]

The Link Management Protocol (LMP) is used for set-up and control of the radio link between two devices. Implemented on the controller.

L2CAP[edit]

The Logical Link Control and Adaptation Protocol (L2CAP) is used to multiplex multiple logical connections between two devices using different higher level protocols. Provides segmentation and reassembly of on-air packets.

In Basic mode, L2CAP provides packets with a payload configurable up to 64 kB, with 672 bytes as the default MTU, and 48 bytes as the minimum mandatory supported MTU.

In Retransmission and Flow Control modes, L2CAP can be configured either for isochronous data or reliable data per channel by performing retransmissions and CRC checks.

Bluetooth Core Specification Addendum 1 adds two additional L2CAP modes to the core specification. These modes effectively deprecate original Retransmission and Flow Control modes:

  • Enhanced Retransmission Mode (ERTM): This mode is an improved version of the original retransmission mode. This mode provides a reliable L2CAP channel.
  • Streaming Mode (SM): This is a very simple mode, with no retransmission or flow control. This mode provides an unreliable L2CAP channel.

Reliability in any of these modes is optionally and/or additionally guaranteed by the lower layer Bluetooth BDR/EDR air interface by configuring the number of retransmissions and flush timeout (time after which the radio flushes packets). In-order sequencing is guaranteed by the lower layer.

Only L2CAP channels configured in ERTM or SM may be operated over AMP logical links.

SDP[edit]

The Service Discovery Protocol (SDP) allows a device to discover services offered by other devices, and their associated parameters. For example, when you use a mobile phone with a Bluetooth headset, the phone uses SDP to determine which Bluetooth profiles the headset can use (Headset Profile, Hands Free Profile, Advanced Audio Distribution Profile (A2DP) etc.) and the protocol multiplexer settings needed for the phone to connect to the headset using each of them. Each service is identified by a Universally Unique Identifier(UUID), with official services (Bluetooth profiles) assigned a short form UUID (16 bits rather than the full 128).

RFCOMM[edit]

Radio Frequency Communications (RFCOMM) is a cable replacement protocol used to generate a virtual serial data stream. RFCOMM provides for binary data transport and emulates EIA-232 (formerly RS-232) control signals over the Bluetooth baseband layer, i.e. it is a serial port emulation.

RFCOMM provides a simple reliable data stream to the user, similar to TCP. It is used directly by many telephony related profiles as a carrier for AT commands, as well as being a transport layer for OBEX over Bluetooth.

Many Bluetooth applications use RFCOMM because of its widespread support and publicly available API on most operating systems. Additionally, applications that used a serial port to communicate can be quickly ported to use RFCOMM.

BNEP[edit]

The Bluetooth Network Encapsulation Protocol (BNEP) is used for transferring another protocol stack’s data via an L2CAP channel. Its main purpose is the transmission of IP packets in the Personal Area Networking Profile. BNEP performs a similar function to SNAP in Wireless LAN.

AVCTP[edit]

The Audio/Video Control Transport Protocol (AVCTP) is used by the remote control profile to transfer AV/C commands over an L2CAP channel. The music control buttons on a stereo headset use this protocol to control the music player.

AVDTP[edit]

The Audio/Video Distribution Transport Protocol (AVDTP) is used by the advanced audio distribution profile to stream music to stereo headsets over an L2CAP channel intended for video distribution profile in the Bluetooth transmission.

TCS[edit]

The Telephony Control Protocol – Binary (TCS BIN) is the bit-oriented protocol that defines the call control signaling for the establishment of voice and data calls between Bluetooth devices. Additionally, “TCS BIN defines mobility management procedures for handling groups of Bluetooth TCS devices.”

TCS-BIN is only used by the cordless telephony profile, which failed to attract implementers. As such it is only of historical interest.

Adopted protocols[edit]

Adopted protocols are defined by other standards-making organizations and incorporated into Bluetooth’s protocol stack, allowing Bluetooth to code protocols only when necessary. The adopted protocols include:

Baseband error correction[edit]

Depending on packet type, individual packets may be protected by error correction, either 1/3 rate forward error correction (FEC) or 2/3 rate. In addition, packets with CRC will be retransmitted until acknowledged by automatic repeat request (ARQ).

Setting up connections[edit]

Any Bluetooth device in discoverable mode transmits the following information on demand:

  • Device name
  • Device class
  • List of services
  • Technical information (for example: device features, manufacturer, Bluetooth specification used, clock offset)

Any device may perform an inquiry to find other devices to connect to, and any device can be configured to respond to such inquiries. However, if the device trying to connect knows the address of the device, it always responds to direct connection requests and transmits the information shown in the list above if requested. Use of a device’s services may require pairing or acceptance by its owner, but the connection itself can be initiated by any device and held until it goes out of range. Some devices can be connected to only one device at a time, and connecting to them prevents them from connecting to other devices and appearing in inquiries until they disconnect from the other device.

Every device has a unique 48-bit address. However, these addresses are generally not shown in inquiries. Instead, friendly Bluetooth names are used, which can be set by the user. This name appears when another user scans for devices and in lists of paired devices.

Most cellular phones have the Bluetooth name set to the manufacturer and model of the phone by default. Most cellular phones and laptops show only the Bluetooth names and special programs are required to get additional information about remote devices. This can be confusing as, for example, there could be several cellular phones in range namedT610 (see Bluejacking).

Pairing and bonding[edit]

Motivation[edit]

Many services offered over Bluetooth can expose private data or let a connecting party control the Bluetooth device. Security reasons make it necessary to recognize specific devices, and thus enable control over which devices can connect to a given Bluetooth device. At the same time, it is useful for Bluetooth devices to be able to establish a connection without user intervention (for example, as soon as in range).

To resolve this conflict, Bluetooth uses a process called bonding, and a bond is generated through a process called pairing. The pairing process is triggered either by a specific request from a user to generate a bond (for example, the user explicitly requests to “Add a Bluetooth device”), or it is triggered automatically when connecting to a service where (for the first time) the identity of a device is required for security purposes. These two cases are referred to as dedicated bonding and general bonding respectively.

Pairing often involves some level of user interaction. This user interaction confirms the identity of the devices. When pairing successfully completes, a bond forms between the two devices, enabling those two devices to connect to each other in the future without repeating the pairing process to confirm device identities. When desired, the user can remove the bonding relationship.

Implementation[edit]

During pairing, the two devices establish a relationship by creating a shared secret known as a link key. If both devices store the same link key, they are said to be paired orbonded. A device that wants to communicate only with a bonded device can cryptographically authenticate the identity of the other device, ensuring it is the same device it previously paired with. Once a link key is generated, an authenticated Asynchronous Connection-Less (ACL) link between the devices may be encrypted to protect exchanged data against eavesdropping. Users can delete link keys from either device, which removes the bond between the devices—so it is possible for one device to have a stored link key for a device it is no longer paired with.

Bluetooth services generally require either encryption or authentication and as such require pairing before they let a remote device connect. Some services, such as the Object Push Profile, elect not to explicitly require authentication or encryption so that pairing does not interfere with the user experience associated with the service use-cases.

Pairing mechanisms[edit]

Pairing mechanisms changed significantly with the introduction of Secure Simple Pairing in Bluetooth v2.1. The following summarizes the pairing mechanisms:

  • Legacy pairing: This is the only method available in Bluetooth v2.0 and before. Each device must enter a PIN code; pairing is only successful if both devices enter the same PIN code. Any 16-byte UTF-8 string may be used as a PIN code; however, not all devices may be capable of entering all possible PIN codes.
    • Limited input devices: The obvious example of this class of device is a Bluetooth Hands-free headset, which generally have few inputs. These devices usually have a fixed PIN, for example “0000” or “1234”, that are hard-coded into the device.
    • Numeric input devices: Mobile phones are classic examples of these devices. They allow a user to enter a numeric value up to 16 digits in length.
    • Alpha-numeric input devices: PCs and smartphones are examples of these devices. They allow a user to enter full UTF-8 text as a PIN code. If pairing with a less capable device the user must be aware of the input limitations on the other device, there is no mechanism available for a capable device to determine how it should limit the available input a user may use.
  • Secure Simple Pairing (SSP): This is required by Bluetooth v2.1, although a Bluetooth v2.1 device may only use legacy pairing to interoperate with a v2.0 or earlier device. Secure Simple Pairing uses a form of public key cryptography, and some types can help protect against man in the middle, or MITM attacks. SSP has the following authentication mechanisms:
    • Just works: As the name implies, this method just works, with no user interaction. However, a device may prompt the user to confirm the pairing process. This method is typically used by headsets with very limited IO capabilities, and is more secure than the fixed PIN mechanism this limited set of devices uses for legacy pairing. This method provides no man-in-the-middle (MITM) protection.
    • Numeric comparison: If both devices have a display, and at least one can accept a binary yes/no user input, they may use Numeric Comparison. This method displays a 6-digit numeric code on each device. The user should compare the numbers to ensure they are identical. If the comparison succeeds, the user(s) should confirm pairing on the device(s) that can accept an input. This method provides MITM protection, assuming the user confirms on both devices and actually performs the comparison properly.
    • Passkey Entry: This method may be used between a device with a display and a device with numeric keypad entry (such as a keyboard), or two devices with numeric keypad entry. In the first case, the display is used to show a 6-digit numeric code to the user, who then enters the code on the keypad. In the second case, the user of each device enters the same 6-digit number. Both of these cases provide MITM protection.
    • Out of band (OOB): This method uses an external means of communication, such as Near Field Communication (NFC) to exchange some information used in the pairing process. Pairing is completed using the Bluetooth radio, but requires information from the OOB mechanism. This provides only the level of MITM protection that is present in the OOB mechanism.

SSP is considered simple for the following reasons:

  • In most cases, it does not require a user to generate a passkey.
  • For use-cases not requiring MITM protection, user interaction can be eliminated.
  • For numeric comparison, MITM protection can be achieved with a simple equality comparison by the user.
  • Using OOB with NFC enables pairing when devices simply get close, rather than requiring a lengthy discovery process.

Security concerns[edit]

Prior to Bluetooth v2.1, encryption is not required and can be turned off at any time. Moreover, the encryption key is only good for approximately 23.5 hours; using a single encryption key longer than this time allows simple XOR attacks to retrieve the encryption key.

  • Turning off encryption is required for several normal operations, so it is problematic to detect if encryption is disabled for a valid reason or for a security attack.

Bluetooth v2.1 addresses this in the following ways:

  • Encryption is required for all non-SDP (Service Discovery Protocol) connections
  • A new Encryption Pause and Resume feature is used for all normal operations that require that encryption be disabled. This enables easy identification of normal operation from security attacks.
  • The encryption key must be refreshed before it expires.

Link keys may be stored on the device file system, not on the Bluetooth chip itself. Many Bluetooth chip manufacturers let link keys be stored on the device—however, if the device is removable, this means that the link key moves with the device.

Air interface[edit]

The protocol operates in the license-free ISM band at 2.402–2.480 GHz.[72] To avoid interfering with other protocols that use the 2.45 GHz band, the Bluetooth protocol divides the band into 79 channels (each 1 MHz wide) and changes channels, generally 1600 times per second. Implementations with versions 1.1 and 1.2 reach speeds of 723.1 kbit/s. Version 2.0 implementations feature Bluetooth Enhanced Data Rate (EDR) and reach 2.1 Mbit/s; this comes with a concomitant higher power consumption. In some cases, the higher data rate is expected to offset this increased drain.

Security[edit]

Overview[edit]

Bluetooth implements confidentiality, authentication and key derivation with custom algorithms based on the SAFER+ block cipher. Bluetooth key generation is generally based on a Bluetooth PIN, which must be entered into both devices. This procedure might be modified if one of the devices has a fixed PIN (e.g., for headsets or similar devices with a restricted user interface). During pairing, an initialization key or master key is generated, using the E22 algorithm.[73] The E0 stream cipher is used for encrypting packets, granting confidentiality, and is based on a shared cryptographic secret, namely a previously generated link key or master key. Those keys, used for subsequent encryption of data sent via the air interface, rely on the Bluetooth PIN, which has been entered into one or both devices.

An overview of Bluetooth vulnerabilities exploits was published in 2007 by Andreas Becker.[74]

In September 2008, the National Institute of Standards and Technology (NIST) published a Guide to Bluetooth Security as a reference for organizations. It describes Bluetooth security capabilities and how to secure Bluetooth technologies effectively. While Bluetooth has its benefits, it is susceptible to denial-of-service attacks, eavesdropping, man-in-the-middle attacks, message modification, and resource misappropriation. Users and organizations must evaluate their acceptable level of risk and incorporate security into the lifecycle of Bluetooth devices. To help mitigate risks, included in the NIST document are security checklists with guidelines and recommendations for creating and maintaining secure Bluetooth piconets, headsets, and smart card readers.[75]

Bluetooth v2.1 – finalized in 2007 with consumer devices first appearing in 2009 – makes significant changes to Bluetooth’s security, including pairing. See the pairing mechanismssection for more about these changes.

Bluejacking[edit]

Main article: Bluejacking

Bluejacking is the sending of either a picture or a message from one user to an unsuspecting user through Bluetooth wireless technology. Common applications include short messages, e.g., “You’ve just been bluejacked!”.[76] Bluejacking does not involve the removal or alteration of any data from the device.[citation needed] Bluejacking can also involve taking control of a mobile device wirelessly and phoning a premium rate line, owned by the bluejacker. Security advances have alleviated this issue.

History of security concerns[edit]

2001–2004[edit]

In 2001, Jakobsson and Wetzel from Bell Laboratories discovered flaws in the Bluetooth pairing protocol and also pointed to vulnerabilities in the encryption scheme.[77] In 2003, Ben and Adam Laurie from A.L. Digital Ltd. discovered that serious flaws in some poor implementations of Bluetooth security may lead to disclosure of personal data.[78] In a subsequent experiment, Martin Herfurt from the trifinite.group was able to do a field-trial at the CeBIT fairgrounds, showing the importance of the problem to the world. A new attack called BlueBug was used for this experiment.[79] In 2004 the first purported virus using Bluetooth to spread itself among mobile phones appeared on the Symbian OS.[80] The virus was first described by Kaspersky Lab and requires users to confirm the installation of unknown software before it can propagate. The virus was written as a proof-of-concept by a group of virus writers known as “29A” and sent to anti-virus groups. Thus, it should be regarded as a potential (but not real) security threat to Bluetooth technology or Symbian OSsince the virus has never spread outside of this system. In August 2004, a world-record-setting experiment (see also Bluetooth sniping) showed that the range of Class 2 Bluetooth radios could be extended to 1.78 km (1.11 mi) with directional antennas and signal amplifiers.[81] This poses a potential security threat because it enables attackers to access vulnerable Bluetooth devices from a distance beyond expectation. The attacker must also be able to receive information from the victim to set up a connection. No attack can be made against a Bluetooth device unless the attacker knows its Bluetooth address and which channels to transmit on, although these can be deduced within a few minutes if the device is in use.[82]

2005[edit]

In January 2005, a mobile malware worm known as Lasco.A began targeting mobile phones using Symbian OS (Series 60 platform) using Bluetooth enabled devices to replicate itself and spread to other devices. The worm is self-installing and begins once the mobile user approves the transfer of the file (velasco.sis) from another device. Once installed, the worm begins looking for other Bluetooth enabled devices to infect. Additionally, the worm infects other .SIS files on the device, allowing replication to another device through use of removable media (Secure Digital, Compact Flash, etc.). The worm can render the mobile device unstable.[83]

In April 2005, Cambridge University security researchers published results of their actual implementation of passive attacks against the PIN-based pairing between commercial Bluetooth devices. They confirmed that attacks are practicably fast, and the Bluetooth symmetric key establishment method is vulnerable. To rectify this vulnerability, they designed an implementation that showed that stronger, asymmetric key establishment is feasible for certain classes of devices, such as mobile phones.[84]

In June 2005, Yaniv Shaked[85] and Avishai Wool[86] published a paper describing both passive and active methods for obtaining the PIN for a Bluetooth link. The passive attack allows a suitably equipped attacker to eavesdrop on communications and spoof, if the attacker was present at the time of initial pairing. The active method makes use of a specially constructed message that must be inserted at a specific point in the protocol, to make the master and slave repeat the pairing process. After that, the first method can be used to crack the PIN. This attack’s major weakness is that it requires the user of the devices under attack to re-enter the PIN during the attack when the device prompts them to. Also, this active attack probably requires custom hardware, since most commercially available Bluetooth devices are not capable of the timing necessary.[87]

In August 2005, police in Cambridgeshire, England, issued warnings about thieves using Bluetooth enabled phones to track other devices left in cars. Police are advising users to ensure that any mobile networking connections are de-activated if laptops and other devices are left in this way.[88]

2006[edit]

In April 2006, researchers from Secure Network and F-Secure published a report that warns of the large number of devices left in a visible state, and issued statistics on the spread of various Bluetooth services and the ease of spread of an eventual Bluetooth worm.[89]

2007[edit]

In October 2007, at the Luxemburgish Hack.lu Security Conference, Kevin Finistere and Thierry Zoller demonstrated and released a remote root shell via Bluetooth on Mac OS X v10.3.9 and v10.4. They also demonstrated the first Bluetooth PIN and Linkkeys cracker, which is based on the research of Wool and Shaked.[citation needed]

Mitigation[edit]

Options to mitigate against Bluetooth security attacks include:[90][91]

  • Enable Bluetooth only when required
  • Enable Bluetooth discovery only when necessary, and disable discovery when finished
  • Do not enter link keys or PINs when unexpectedly prompted to do so
  • Remove paired devices when not in use
  • Regularly update firmware on Bluetooth-enabled devices

Health concerns[edit]

Bluetooth uses the microwave radio frequency spectrum in the 2.402 GHz to 2.480 GHz range.[72] Maximum power output from a Bluetooth radio is 100 mW for class 1, 2.5 mW for class 2, and 1 mW for class 3 devices. Even the maximum power output of class 1 is a lower level than the lowest powered mobile phones.[92] UMTS & W-CDMA outputs 250 mW,GSM1800/1900 outputs 1000 mW, and GSM850/900 outputs 2000 mW.

Interference caused by USB 3.0[edit]

USB 3.0 devices, ports and cables have been proven to interfere with Bluetooth devices due to the electronic noise they release falling over the same operating band as Bluetooth. The close proximity of Bluetooth and USB 3.0 devices can result in a drop in throughput or complete connection loss of the Bluetooth device/s connected to a computer.[93]

Various strategies can be applied to resolve the problem, ranging from simple solutions such as increasing the distance of USB 3.0 devices from any Bluetooth devices or purchasing better shielded USB cables. Other solutions include applying additional shielding to the internal Bluetooth components of a computer.[94]

Bluetooth award programs[edit]

The Bluetooth Innovation World Cup, a marketing initiative of the Bluetooth Special Interest Group (SIG), was an international competition that encouraged the development of innovations for applications leveraging Bluetooth technology in sports, fitness and health care products. The aim of the competition was to stimulate new markets.[95]

The Bluetooth Innovation World Cup morphed into the Bluetooth Breakthrough Awards in 2013. The Breakthrough Awards[96] Bluetooth program highlights the most innovative products and applications available today, prototypes coming soon, and student-led projects in the making.

See also[edit]

References[edit]

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Bilgisayar

Bilgisayar, kendisine verdiğimiz bilgileri istediğimizde saklayabilen, istediğimizde geri verebilen cihaza denir. İlk elektrikli bilgisayar ENIAC‘tır.

Bilgisayarlar tarih boyunca çok farklı biçimlerde karşımıza çıkmışlardır. 20. yüzyılın ortalarındaki ilk bilgisayarlar büyük bir oda büyüklüğünde olup, günümüz bilgisayarlarından yüzlerce kat daha fazla güç tüketiyorlardı. 21. yüzyılın başına varıldığında ise bilgisayarlar bir kol saatine sığacak ve küçük bir pil ile çalışacak duruma geldiler. Bu kadar küçük imal edilebilmelerinin temel nedeni 1969 yılında yarı iletkenler ile çok küçük alanlara sığdırılabilen devreler yapılabilmesidir. Şu anda kullandığımız bilgisayarlar Intel’in ilk işlemci unvanına sahip olan 4004‘ten sonra bilgisayar teknolojisi hız kazanmıştır. Toplumumuz kişisel bilgisayarı ve onun taşınabilir eşdeğeri, dizüstü bilgisayarını, bilgi çağının simgeleri olarak tanıdılar ve bilgisayar kavramıyla özdeşleştirdiler. Günümüzde çok yaygın kullanılmaktadırlar. Bilgisayarın temel çalışma prensibi ikili sayı sistemi yani sadece 0 ve 1 den oluşan kodlamalardır.

İstenilen yazılımı kayıt edip istenilen zamanda çalıştırabilmeleri bilgisayarları çok yönlü kılıp hesap makinelerinden ayıran ana özellikleridir.Church-Turing tezi bu çok yönlülüğün matematiksel ifadesidir ve herhangi bir bilgisayarın bir diğer bilgisayarın görevlerini yerine getirebileceğinin altını çizer. Dolayısıyla, karmaşıklıkları ne düzeyde olursa olsun, cep bilgisayarından süper bilgisayarlara kadar, bellek ve zaman sınırı olmadığı takdirde hepsi aynı görevleri yerine getirebilirler.

Tarihçe[değiştir | kaynağı değiştir]

Geçmişte ‘bilgisayar’ olarak bilinen birçok aygıt günümüz ölçütlerine göre bu tanımı hak etmemektedirler. Başlangıçta bilgisayar sözcüğü hesaplama sürecini kolaylaştıran nesnelere verilen bir ad konumundaydı. Bu ilk dönemin bilgisayar örnekleri arasında sayı boncuğu (abaküs) ve AntiKitira Makinesi (M.Ö 150- M.Ö100) sayılabilir. Yüzyıllar sonra, Orta Çağ sonundaki yeni bilimsel keşifler ışığında, Avrupalı mühendisler tarafından geliştirilen bir dizi makinesel hesaplama aygıtlarının ilki ise, Wilhelm Schickard‘a (1623) aittir.

Ancak, yazılımlanabilir (veya kurulabilir) olmamaları nedeniyle bu aygıtların hiçbiri günümüz bilgisayar tanımına uymamaktadır. 1801 yılında Joseph Marie Jacquard‘ın dokumatezgahındaki işlemi otomatikleştirmek adına ürettiği delikli kartlar ise bilgisayarların gelişme sürecindeki, kısıtlı da olsa, ilk yazılımlanabilme (kurulabilme) izlerinden sayılır. Kullanıcının sağladığı bu kartlar sayesinde, dokuma tezgahı kart üzerindeki delikler ile tarif edilen çizime işleyişini uyarlayabiliyordu.

1837 yılında Charles Babbage, adını Analytical Engine (çözümlemeli veya analitik makine) koyduğu, ilk tam yazılımlanabilir makinesel bilgisayarı kavramsallaştırıp tasarladı. Ancak parasal nedenler ve üzerindeki çalışmalarının sonlanamaması nedeniyle bu makineyi geliştiremedi.

Delikli kartların ilk büyük ölçekli kullanımı ise Herman Hollerith tarafından, 1890 yılında muhasebe işlemlerinde kullanılmak üzere tasarlanan hesap makinesidir. Hollerith’in o dönemde bağlı olduğu işletme ise sonraki yıllarda küresel bilgisayar devine dönüşecekIBM‘dir. 19. yüzyılın sonlarına varıldığında, gelecek yıllarda bilişim donanım ve kuramlarının gelişimine büyük katkıda bulunacak uygulayımlar (teknolojiler) ortaya çıkmaya başlamıştılar: delikli kartlar, Boole cebiri, boşluk tüpleri ve teletip aygıtları.

20. yüzyılın ilk yarısında ise, birçok bilimsel gereksinim, gittikçe karmaşıklaşan örneksel (analog) bilgisayarlar ile giderildiler. Ancak günümüz bilgisayarlarının yanılmazlık düzeyinden hâlâ uzaktılar.

1930‘lar ve 1940‘lar boyunca bilgisayar uygulayımı gelişmeye devam etti, ve sayısal elektronik bilgisayarın ortaya çıkışı ancak elektronik devrelerinin buluşundan (1937) sonra gerçekleşebildi. Bu dönemin önemli çalışmaları arasında aşağıdakiler sayılabilir:

ENİAC, von Neumann mimarisini uygulayan ilk bilgisayarlardandır.

  • Konrad Zuse‘nin “Z makineleri”. Z3 (1941) ikili sayı tabanına dayalı işleyip, gerçel sayılar ile işlem yapabilen ilk makinedir. 1998 yılında Z3’ün Turing uyumlu olduğu kanıtlanmış ve böylece ilk bilgisayar unvanını edinmiştir.
  • Atanasoff-Berry Bilgisayarı (1941) boşluk tüplerine dayalı olup, ikili sayı tabanının yanı sıra, sığaç tabanlı bellek donanımına sâhipti.
  • İngiliz yapımı Colossus bilgisayarı (1944), kısıtlı yazılımlanabilirliğine (kurulabilirliğine) karşın, binlerce tüp kullanımının yeterince güvenilir bir sonuç verebileceğini göstermiştir. II. Dünya Savaşı‘nda Alman silahlı kuvvetlerinin gizli iletişimlerini çözümlemek için kullanılmıştır.
  • Harvard Mark I (1944), kısıtlı kurulabilirliğe sahip bir bilgisayar.
  • ABD Ordusu tarafından geliştirilen ENIAC (1946), onluk sayı tabanına dayalı olup ilk genel kullanım amaçlı elektronik bilgisayar unvanına sahiptir.

ENIAC’ın olumsuz yanlarını saptayan geliştiricileri, daha esnek ve zarif bir çözüm üzerinde çalışıp, artık saklı yazılım mimarisi veya daha çok von Neumann mimarisi olarak tanınan tasarımı önerdiler. Bu tasarımdan ilk olarak John von Neumann (1945) yılında gerçekleştirdiği bir yayında söz etmesinden sonra, bu mimariye dayalı olarak geliştirilen bilgisayarlardan ilki Birleşik Krallık‘ta tamamlandı (SSEM). Aynı mimariye bir yıl sonra kavuşan ENIAC’a ise EDVAC adı verildi.

Günümüz bilgisayarlarının neredeyse tamamının bu mimariye uyumlu duruma gelmesi ile bilgisayar sözcüğünün tanımı olarak da kullanılmaktadır. Dolayısıyla bu tanıma göre geçmişteki aygıtlar bilgisayar olarak sayılmasalar da, tarihsel bağlamda yine de o biçimde anılmaktadırlar. Her ne kadar 1940‘lardan bu yana bilgisayar uygulayımı köklü değişiklikler geçirmiş olsa da, çoğunluğu von Neumann mimarisine sadık kalmıştır.

1980’lerde Bir IBM PC

Boşluk tüpüne dayalı bilgisayarlar 1950‘ler boyunca kullanımda kaldıktan sonra, 1960‘larda daha hızlı ve ucuz olan geçirgeç (transistör) tabanlı bilgisayarlar yaygınlık kazandı. Bu etkenlerin sonucunda bilgisayarların daha önce görülmemiş bir düzeyde toplu üretimine geçirildi. 1970‘lere varıldığında tümleşik devre uygulayımı ve Intel 4004 gibi mikroişlemcilerin geliştirilmesi sayesinde bir kez daha büyük bir başarım ve güvenilirlik artışının yanı sıra, maliyet düşüşü de yaşandı. 1980‘lerde artık bilgisayarlar, çamaşır makinesi gibi günlük hayat kullanımındaki birçok makinesel aygıtın denetleyici donanımlarındaki yerlerini almaya başlamışlardı. Yine aynı dönemde, kişisel bilgisayarlar yaygınlık kazanıyorlardı. Son olarak 1990‘lardaki Internet’in gelişimi ile de bilgisayarlar televizyon ve telefon gibi alışılmış birer aygıt hâline gelmişlerdir.

Von Neumann mimarisine göre bilgisayarlar başlıca dört bileşenden oluşurlar bilgisayarda aritmetik mantık vardır.

von Neumann mimarisine göre bilgisayar yapısı.

Bellek[değiştir | kaynağı değiştir]

Bir bilgisayarın belleği, sayılar içeren bir hücreler bütünü olarak düşünülebilir. Her hücreye yazılabilir ve içeriği okunabilir. Her hücrenin kendisine özel bir adresi vardır. Bir komut örneğin 34 sayılı hücrenin içeriğini 5.689 sayılı hücreyle toplayıp 78. hücreye yerleştirmekolabilir. İçerdikleri sayılar herhangi bir şey olabilir, sayı, komut, adres, harf, vb. İçeriğinin doğasını ancak onu kullanan yazılım belirler. Günümüz bilgisayarlarının çoğunluğu veriyi kaydetmek için ikili sayıları kullanır ve her hücre 8 bit (yani bir bayt) içerebilir.

Mikroişlemci von Neumann mimarisinin temel öğelerindendir.

Kişisel bilgisayar: (1) Ekran, (2) Ana kart (3)İşlemci (CPU) (4) Bellek (RAM) (5) Genişletme Kartları (PCI-X, AGP, v. b.) (6) Güç Kaynağı (7) Optik Disk Sürücü (DVD, CD, v. b.) (8) Sabit Disk (9) Klavye (10)Fare

Dolayısıyla bir bayt 255 farklı sayıyı ifade edebilir, bunlar ancak 0 dan 255’e veya -128 den +127’ye olabilirler. Yan yana yerleşmiş birden fazla bayt kullanıldığında ise (genelde 2, 4 veya 8) çok daha büyük sayıların kaydedilmesi mümkün olur. Çağımız bilgisayarlarının bellekleri milyarlarca bayt içermektedirler.

Bilgisayarlarda üç adet bellek türü bulunur. İşlemci içerisinde yer alan yazmaçlar, son derece hızlı ancak çok sınırlı sığaya sahiptirler. İşlemcinin çok daha yavaş olan ana belleğe olan erişim gereksinimini gidermek için kullanılırlar. Ana bellek ise Rastgele erişimli bellek (REB veya RAM, Random Access Memory) ve Salt okunur bellek (SOB veya ROM, Read Only Memory) olmak üzere ikiye ayrılır. RAM’e istenildiği zaman yazılabilir ve içeriği ancak güç sürdüğü sürece korunur. ROM’sa sadece okunabilen ve önceden yerleştirilmiş bilgiler içerir. Bu içeriği güçten bağımsız olarak korur. Örneğin herhangi bir veri veya komut RAM’da bulunurken, bilgisayar donanımını düzenleyen BIOS ROM’da yer alır.

Son bir bellek alt türü ise önbellektir (cache memory). İşlemci içerisinde yer alır ve yazmaçlardan büyük sığaya sahip olmanın yanı sıra ana bellekten de hızlıdır.

Sabit diskler bilgisayarların en çok tanınan Giriş/Çıkış birimlerindendirler.

G/Ç bir bilgisayarın dış dünyadan veri alışverişinde bulunmak için kullandığı araçtır. Yaygın olarak kullanılan giriş birimleri arasında klavye ve fare, çıkış için ise ekran (veyagörüntüleyici, monitör), hoparlör ve yazıcı sayılabilir. Sabit ve optik diskler ise her iki görevi de üstlenirler.

Bilgisayar ağları[değiştir | kaynağı değiştir]

Bilgisayarlar 1950`lerden beri çoklu ortamlar arasında bilgi koordinasyonu kurmak amacıyla kullanıldı. ABD ordusunun (SAGE) sistemi bu tür sistemlerin geniş kapsamlı ilk örneğiydi ve bu sistem (Sabre) gibi birçok özel amaçlı ticari sisteme öncülük etti.1970‘lerde ABD‘li mühendisler ordu içerisinde yürütülen bir tasarı çerçevesinde bilgisayarları birbirleri ile bağlayıp (ARPANET), günümüzde bilgisayar ağı olarak bilinen yapının temellerini attılar. Zaman içerisinde bu bilgisayar ağı, ordu ve akademik birimler ile de sınırlı kalmayıp genişledi ve bugün milyonlarca bilgisayar içeriden Bilgisunar(İnternet veya Genel ağ) oluştu. 1990‘lara gelindiğinde ise, İsviçre‘nin CERN araştırma merkezinde geliştirilen Küresel ağ(World Wide Web, WWW) adlı iletişim kuralları, e-posta gibi uygulamalar ve ethernet gibi ucuz donanımsal çözümler ile bilgisayar ağları yaygınlık kazandılar.

Donanım[değiştir | kaynağı değiştir]

Disket sürücü, sabit disk ve optik diskin bulunduğu çevresel birimlerin toplandığı standart tip bilgisayar kasası

Donanım kavramı bir bilgisayarın tüm dokunulabilir bileşenlerini kapsar.

Donanım örnekleri
Çevresel birimler (Giriş/çıkış) Giriş Fare, Klavye, Oyun çubuğu, Tarayıcı
Çıkış Monitör, Yazıcı, Hoparlör
Her ikisi Disket sürücü, Sabit disk, Optik disk
Bağlantı birimleri Kısa menzil RS-232, SCSI, PCI, USB
Uzun menzil (Bilgisayar ağları) Ethernet, ATM, FDDI

Giriş/çıkış birimleri[değiştir | kaynağı değiştir]

Giriş/çıkış, bilgi işlem dizgesinin değişik işlevsel birimleri (alt sistemleri) arasındaki iletişimi veya bu arayüzlere doğrudan bilgi sinyallerini göndermeyi sağlar.

Girişler, değişik birimlerden alınan sinyallerdir. Çıkışlar ise bu birimlere gönderilen sinyallerdir. I/O aygıtları bir kullanıcı (veya başka sistemler) tarafından bilgisayar ile bağlantı kurabilmek için kullanılır. Örnek olarak, klavye ve fare bilgisayarın giriş aygıtlarıdır. Ekran, hoparlör ve yazıcı ise bilgisayarın çıkış aygıtlarıdır. Değişik aygıtlar bilgisayar ile bağlantı gerçekleştirebilmeleri için giriş ve çıkış sinyallerini kullanırlar. Modem ve bağlantı kartları örnek olabilir.

Klavye ve fare kullanıcıların fiziksel hareketlerini giriş olarak alırlar ve bu fiziksel hareketleri bilgisayarların anlayabileceği düzeye getirirler. Çıkış birimleri ise (yazıcı,hoparlör,ekran gibi) giriş sinyali olarak bilgisayarın ürettiği çıkış sinyallerini alırlar ve bu sinyalleri kullanıcıların görebileceği ve okuyabileceği çıktılara çevirirler.

Bilgisayar mimarisinde merkezi işlem birimi (CPU) ve ana bellek bilgisayarın kalbini oluşturmaktadır. Çünkü bellek kendi talimatları ile merkezî işlem birimindeki verileri doğrudan okuyabilir ve merkezi işlem birimine doğrudan veri yazabilir. Örnek olarak, bir disket sürücüsü I/O sinyallerini dikkate alır. Merkezi işlem biriminin I/O yöntemlerini sağlaması alt düzey bilgisayar programlamacılığında aygıt sürücülerinin tamamlanmasına yardımcı olur.

Üst düzey işletim sistemleri ve üst düzey programlamacılık ideal I/O kavramlarını ve temel öğeleri ayırt ederek çalıştırmaya olanak sağlamaktadır. Örneğin C programlama dili yazılımların I/O’larını düzenlemek için içerisinde fonksiyonlar bulundurmaktadır. Bu fonksiyonlar dosyalardan veri okunmasını ve bu dosyaların içerisine veri yazılmasını sağlar.

Yazılım[değiştir | kaynağı değiştir]

Yazılım kavramı bilgisayardaki özdek (maddi) olmayan tüm bileşenleri tanımlar: yazılımlar, iletişim kuralları ve veriler hepsi yazılımdır.

Yazılım
İşletim sistemi Unix/BSD UNIX V, AIX, HP-UX, Solaris (SunOS), FreeBSD, NetBSD, IRIX
GNU/Linux Linux dağıtımları
Microsoft Windows Windows 3.0, Windows 3.1, Windows 95, Windows 98, Windows NT, Windows CE, Windows XP, Windows Vista, Windows 7,Windows 8 Windows 8.1 Windows 10
DOS DOS/360, QDOS, DRDOS, PC-DOS, MS-DOS, FreeDOS
Mac OS Mac OS X
Gömülü ve Gerçek zamanlı işletim sistemileri Gömülü işletim sistemleri dizelgesi
Kütüphaneler Çoklu ortam DirectX, OpenGL, OpenAL
Yazılımlama kütüphanesi C kütüphanesi
Veriler İletişim kuralı TCP/IP, Kermit, FTP, HTTP, SMTP, NNTP
Belge biçimleri HTML, XML, JPEG, MPEG, PNG
Kullanıcı arayüzü Grafiksel kullanıcı arayüzü (WIMP) Microsoft Windows, GNOME, KDE, QNX Photon, CDE, GEM
Metinsel kullanıcı arayüzü Komut satırı, Kabuk
Diğer
Uygulama Ofis Kelime işlemci, Masaüstü yayıncılık, Sunum yazılımı, Veri tabanı yönetim sistemi, Hesap çizelgesi, Muhasebe yazılımı
Bilgisiyar Erişimi Tarayıcı, E-posta istemcisi, Küresel ağ sunucusu, Anlık ileti yazılımı
Tasarım Bilgisayar destekli tasarım, Bilgisayar destekli yapım
Grafikler Hücresel grafik düzenleyici, Yöneysel grafik düzenleyici, 3B modelleyici, Canlandırma düzenleyici, 3B bilgisayar grafikleri,Video düzenleme, Görüntü işleme
Sayısal ses Sayısal ses düzenleyici, Ses oynatıcı
Yazılım mühendisliği Derleyici, Çevirici, Yorumlayıcı, Hata ayıklayıcı, Metin düzenleyici, Tümleşik geliştirme ortamı, Başarım incelemesi, Değişiklik denetimi, Yazılım yapılandırma yönetimi
Oyunlar Strateji, Macera, Bulmaca, Benzetim, Rol yapma oyunu, Etkileşimli kurgu
Ek Yapay +, Antivirüs yazılımı, Belge yönetici

Programlama dilleri[değiştir | kaynağı değiştir]

Programlama dilleri
Programlama dilleri listesi Programlama dillerinin bölümsel listesi, Programlama dillerinin abecesel listesi, İngilizce tabanlı olmayan programlama dilleri
Çokça kullanılan Assembly dilleri x86
Çokça kullanılan Yüksek düzey diller BASIC, [Delphi, C, C++, C#, COBOL, D, Fortran, Java, Lisp, Pascal
Çokça kullanılan Betik dilleri Bourne shell, JavaScript, Python, Ruby, PHP, Perl

Kişisel Bilgisayarların Kilometre Taşları[değiştir | kaynağı değiştir]

19501970 Büyük kurumlarda anaçatı bilgisayarlar kullanılıyordu.
1971 Yonganın geliştirilmesiyle bilgisayarlar çok küçük hâle geldi. Kişisel kullanıma yönelik ilk bilgisayar satıldı. Kendi monitörü yoktu, televizyon ekranını kullanıyordu.
1975 Bir ekranı ve klavyesi takılı olan ilk bilgisayar satıldı. Bilgisayara “Uzay Yolu” adlı televizyon dizisindeki bir gezegenden esinlenilerek Altair adı verilmişti.
1977 Tamamı birleştirilmiş, ekranı ve klavyesi bulunan, kullanıma hazır halde ilk bilgisayar üretildi.
1981 Bir ABD şirketi olan IBM, ilk kişisel bilgisayarı üretir. Kısa süre sonra diğer şirketler, IBM gibi kendi bilgisayarlarını tasarlar.
1983 Apple, faresi olan bir bilgisayar olan Macintosh‘u üretir. Bilgisayar çizgeleri (grafik) kullanılmaya başlanır.
1985 Microsoft şirketi Windows 1.0’ı piyasaya sürer.
1992 Linus Torvalds, Linux 1.0’ı duyurur.
1997 Avuçiçi bilgisayarlar piyasaya yeni yeni çıkar.

internet

İnternet bilgisayar sistemlerini birbirine bağlayan elektronik iletişim ağıdır.[1] TDK, İnternet sözcüğüne karşılık olarak genel ağı önermiştir.[2] İnternet yerine zaman zaman sadece net sözcüğü de kullanılır.[3]

İnternet, çok protokollü bir ağ olup birbirine bağlı bilgisayar ağlarının tümü olarak da tanımlanabilir. Binlerce akademik ve ticari ağ iledevlet ve serbest bilgisayar ağının birbirine bağlanmasıyla oluşmuştur. Bilgisayarlar arasında bilgi çeşitli protokollere göre paketler halinde transfer edilir. İnternet üzerinde elektronik posta ve birbirine bağlı sayfalar gibi çok çeşitli bilgiler ve hizmetler vardır. İnternet üzerinden oyunlar da oynanabilir.

İnternet’in kökeni, hataya dayanıklı, sağlam ve özel bir bilgisayar ağı kurmak isteyen Amerika Birleşik Devletleri hükümeti tarafından1960 yılındaki araştırmalara dayanır. 1980’lerde Ulusal Bilim Vakfı tarafından yeni bir ABD omurgasının finansmanı için toplanan özel fonlar, Dünya çapında katılım ve birçok özel ağın birleşmesine neden olmuştur. 1990’larda uluslararası bir ağın yaygınlaşması ile İnternet, modern insan hayatının temelinde yer almıştır.

Etimoloji[değiştir | kaynağı değiştir]

1985 yılında kullanılmaya başlayan[1] İngilizce Internet kelimesi, “kendi aralarında bağlantılı ağlar” anlamına gelen Interconnected Networks teriminin kısaltmasıdır.[kaynak belirtilmeli]Inter- öneki İngilizce’de arasında ve karşılıklı anlamlarına gelir. Net kelimesi ise anlamına gelir.[4]

Zaman zaman İnternet kelimesi yerine kullanılan “WWW” kısaltması ise World Wide Web (Dünya Çapında Ağ) sözcüklerinin akronimidir ve İnternet ile eş anlamlı değildir.

Geçmiş[değiştir | kaynağı değiştir]

İnternet üzerinden ağ sayesinde iletişim kuran bilgisayar sistemleri olan askeri iletişim sistemi Semi-Automatic Ground Environment (SAGE) ve ticari havayolu rezervasyon sistemi olan Semi-Automatic Business Research Environment (SABRE) 1950’lerin başında başlamıştır. 1960 larda ise the Advanced Research Projects Agency (ARPA), ABD’nin savunma sistemi için the Advanced Research Projects Agency Network (ARPANET) nin tasarım finansmanı olmaya başladı. 1960’larda oluşturulan projelerin sayesinde 1969’da İnternet o dönemin zirvesine ulaşmıştır. Bu tarihten sonra da ARPANET bildiğimiz modern İNTERNET olarak hayatımıza girmiş oldu. 70‘li yılların başında Amerikan üniversitelerinde bu projeden yararlanma imkânı verilmesinin ardından e-posta (SMTP) ve NNTP uygulamaları yaygınlık kazanmaya başlamıştır. Bunları FTP ve HTTP izlemiştir. 30 Nisan 1993’te CERNtarafından WWW ön eki ile İnternet kamunun ulaşabileceği şekle getirildi. 12 Nisan 1993 tarihinde ODTÜ‘den Ankara-Washington arasında kiralık hat ile Türkiye’de ilk İnternet bağlantısı gerçekleşti.[5]

Kişisel kullanım[değiştir | kaynağı değiştir]

Kişisel bilgisayarlar ile İnternet’e bağlanabilmek için genellikle bir telefon hattına ihtiyacı vardır. Bunun yanında uydu, kablo ve Wi-Fi diye adlandırılan radyo yayınlarla da İnternet’e bağlanılabilir. En yaygın olanı ise bir analog modem ile belli hızda bir İnternet servisi veren bir şirketin hizmetinden yararlanmaktır. Modemin ayarları şirketin verdiği servis telefon numarası ve özelliklerine göre ayarlanıp, bağlan komutu verilir. Analog modem bilgisayarın dijital verileri (bits) çeşitli ses frekanslarına çevirip telefon hattından İnternet servisine ulaştırmakta olup tersine aynı yöntemle verileri almaktadır.

Her görüntülenen sitenin bir adresi numarası vardır Bu, dört yuvadan oluşan ve her yuvanın 0 ile 255 arası değeri olan bir adresdir. Fakat kullanıcı bu yalın sayı değerini her çağıracağı site için aklında tutamayacağı için bu adresleri Web sayfasına eş değer tutan DNS bilgisayarları vardır. Bunların görevi ise görüntülenecek her site ismine eş değer IP adresini hazır tutmak ve bilgi taşıma protokolünün paketlerini (TCP/IP) bu adrese yönlendirmektir. Böylece az uğraşla İnternet gezgincisinin çağırdığı sitedeki bilgilere ulaşılabilinir.

Günümüzde, analog modemlerin yerini daha hızlı ve daha az hatalı olan dijital ( ADSL) modemler almaktadır. Bunların kullanım ücretleri, çoğul katılımın artması sayesinde makul ödenebilir düzeye inmektedir. ADSL bir analog modemden 10x – 1500x kez hıza sahip olup, canlı videolu sohbet imkânı yanında bir sinema filmini kısa bir zaman dilimi içinde yükleme imkânı vermektedir.

WWW. Dünyası yanında dosya indirimi sanal sohbet odaları, eCommerce (sanal ticaret), tartışma mekânları (forum), İnternet üzerinden sohbet doğrudan mesaj (IM) gibi kullanım alanlarını, bugün bütün Dünya’da yüzmilyonlarca insan kullanmaktadırlar.

Günümüzdeki kullanımı[değiştir | kaynağı değiştir]

Günümüzde özellikle mobil İnternet aygıtlarıyla hemen hemen her yerden İnternet’e erişilebilir. Kablosuz ağ bağlantısını destekleyen cep telefonları, taşınabilir oyun konsolları,dizüstü bilgisayarlar gibi cihazlarla kullanıcılar istedikleri zaman istedikleri yerden İnternet’e ulaşabilirler. Servis sağlayıcılarının hizmetleri ve sundukları kablosuz veri iletim ücretleri diğer erişim yöntemlerine göre daha yüksek olabilir.

Yaygınlaşması[değiştir | kaynağı değiştir]

Radyo, televizyon ve İnternet’in bulunuşundan 50 milyon kullanıcıya ulaşmak için geçen süre incelendiğinde; radyo için 38 yıl, televizyon için 13 yıl iken, İnternet için sadece beş yıldır.

İnternet Türkiye‘ye 1994 yılında gelmiştir ve geldikten sonra Türkiye’de kullanımı yaygınlaşmıştır. İnternet günümüzde de yaygın olan yediden 70’e herkesin kullandığı teknoloji ürünü olan ve her gün yenilenen bir bilgi kaynağı teknoloji ürünüdür.

Terimler[değiştir | kaynağı değiştir]

İnternet ve “World Wide Web” sözcükleri günlük kullanımda genelde aynı anlamda kullanılır fakat aynı şey değillerdir. İnternet yazılım ve donanım altyapısı ile sağlanan küresel veri iletişim dizgesidir fakat web İnternet ile sağlanan iletişim şekillerinden yalnızca birisidir.

Site[değiştir | kaynağı değiştir]

Vikipedi sitesinin 16 Eylül 2010 tarihindeki ana sayfası.

İnternet sitesi, İnternet üzerinden yazı, resim ve diğer dosyaların paylaşıldığı dijital sayfalar grubudur. İnternet’in, ekran aracılığıyla görsel olarak, hoparlörler aracılığıyla da işitsel olarak kullanıldığı ortamlardır. Bir İnternet sitesi bir sayfadan ya da binlerce sayfadan oluşabilir. Bir sitenin kullanıcının karşısına çıkan ilk sayfasına “ana sayfa” denir. Ana sayfadan, linkler(bağlantılar) aracılığıyla sitenin diğer kısımlarına veya yabancı sitelere ulaşılabilir.

Modem[değiştir | kaynağı değiştir]

Ana madde: Modem

Telefon sinyallerini sayısal verilere çeviren ve bilgisayarın İnternet’e bağlanmasını sağlayan elektronik alettir.

TCP/IP[değiştir | kaynağı değiştir]

İnternet’i çağın haberleşme ortamı yapan ise TCP/IP dosya iletişim protokolüdür. Açılımı; Transmission Control Protocol/Internet Protocol’dur (Aktarım Denetim Kuralı/İnternet Kuralı).

TCP/IP, özde makinelerin konuşmasını sağlayan, işletim sisteminden veya uygulama yazılımlarından bağımsız bir kuralıdır. Bu özelliği sayesinde, cep telefonu, kişisel bilgisayar veya bir saat dahi İnternet’e bağlı diğer cihazlarla konuşabilir.

Adres işareti (@)[değiştir | kaynağı değiştir]

Ana madde: @

İnternet’te sık kullanılan sembollerden birisi @’dir (okunuşu: et). Elektronik posta adreslerinde kullanıcı ismi ile gönderilen hedef alanını (site adı) ayırır. Adres işareti, güzel a olarak da bilinir. Türk Dil Kurumu çengelli a ya da kuyruklu a karşılıklarını önermiştir.

E-posta[değiştir | kaynağı değiştir]

Ana madde: E-posta

E-posta (İngilizce: e-mail) “elektronik posta” sözcüklerinin kısaltmasıdır. İnternet üzerinden gönderilen ve alınan dijital mektuplardır. Günlük kullanımda “mail” (okunuşu: meyl) olarak da geçer. Görsel olarak kâğıt bir mektup ile aralarında büyük bir fark yoktur. E-postalara resim, müzik, video gibi her türlü dosya türü eklenebilir ve alıcının bilgisayarına transfer edilebilir. Her gün Dünya’da milyarlarca e-posta gönderilmektedir. Ucuzluğu ve kolaylığı nedeniyle kâğıt mektuplardan daha yaygın olarak kullanılmaktadır ancak güvenilirliğinin yetersizliği nedeniyle resmi işlerde kullanımı oldukça kısıtlıdır.

E-posta hesapları bu hizmeti veren çeşitli sitelerden ücretsiz veya belirli bir ücret karşılığında açılabilir. E-posta adresleri; kullanıcı adı, adres işareti, hesabın oluşturulduğu sitenin e-posta sunucusunun adı, nokta (.) ve site uzantısının aralık bırakılmadan yazılması ile oluşur. Örneğin: vikipedist@vikipedi.com

İnternet’e bağlanabilen cihazlara gelebilecek dijital tehlikeler[değiştir | kaynağı değiştir]

Pek çok faydasının yanında maalesef İnternet çeşitli tehlikelere de kapımızı açar. İnternet ağına bağlandığınız andan itibaren çeşitli zararlı yazılımların saldırılarına mazur kalabilir; “hacker” diye tanımlanan bilgisayar korsanlarının bilgisayarınızı ele geçirebileceğine şahit olabilir; çevrimiçi bankacılık aracılığı ile banka hesabınız boşaltılabilir; cihazınız anlayamadığınız garip davranışlarda bulunmaya başlayabilir.

Virüsler[değiştir | kaynağı değiştir]

Bilgisayar virüsleri, zararlı kod ve programcıklardır. Bilgisayarlara veri taşıyan diskler, taşınabilir hafızalar, yerel ağlar ya da İnternet aracılığıyla girerler. Kendini kopyalamak, verileri silmek, istenmeyen programları çalıştırmak, kişisel (şifre vb.) bilgileri yaymak gibi zararlı faaliyetleri gerçekleştirirler. Bilgisayarlara zarar verme yöntemleri canlılarda hastalık meydana getiren virüslere benzediği için bu isim uygun görülmüştür.

Bazı virüsler bir programın zaman aşımına uğramış veya bozunmuş yani istem dışı çalışan ve genellikle görevleri belli olmayan halleridir. Kötü emeller için hazırlanan Trojan, Win32, Win29, Solucan vb. virüsler başkaları tarafından bulaştırılırlar. Virüslerin kendi kendine oluşması zordur, farkedildiğinde derhal temizlenmesi gerekir.

Casus programlar[değiştir | kaynağı değiştir]

Malware, adware, spyware gibi çeşitli şekillerde adlandırılan casus programlar, bilgisayarlardan bilgi toplamak amacıyla oluşturulmuş küçük yazılımlardır. Virüs gibi faaliyet gösterirler bu nedenle bir kısmı virüs olarak da adlandırılır. Bilgisayar kullanıcısının İnternet alışkanlıkları, hesap numaraları gibi bilgileri zararlı kişi ve kuruluşlara ulaştırırlar. Bazıları çok zararlı olmamakla birlikte, veri toplarken arka planda çalışarak bilgisayar hafızasını gereksiz yere işgal ederler. Bazı casus programlar ise resmi kuruluşlar tarafından suçluları ve terörist faaliyetleri izlemek amacı ile geliştirilmiştir. Ayrıca devletler eski casusluk yöntemleri yerine bilgisayar ortamında casusluk yöntemlerine başvurmakta buna bağlı olarak risk ve maliyeti düşürmektedirler.

Bilgisayar korsanları[değiştir | kaynağı değiştir]

Başka insanların bilgisayar, telefon gibi elektronik cihazlarlarının bilgilerine izinsiz olarak ulaşarak kişisel bilgilerini çalan kişilerdir. Fakat bu gerekmez. Bazı hackerlara yer verilen sitelerde hackerlar sitelerin teknik gelişimine yardım ederler. Bunun Vikipedi‘de örneği Teknisyenler‘dir.

Bu tehlikelerden korunma yöntemleri[değiştir | kaynağı değiştir]

Bilgisayarları İnternet’ten gelebilcek tehditlere karşı korumanın en etkin yolu anti-virüs, anti-casus yazılımları ve güvenlik duvarı yazılımları kullanmaktır. Norton, Kaspersky, McAfeegibi günümüzdeki birçok ticari güvenlik yazılımı, bu üç korumayı da içerir.

İnternet’ten gelebilecek diğer tehlikeler[değiştir | kaynağı değiştir]

İnternet’in yaygınlaşması sonucu her gün milyonlarca insanın hiç tanımadığı insanlarla şahsi bilgilerini paylaşması, virüslerden çok daha vahim bir tehdit oluşturmaktadır. İnternet’in dikkatsiz kullanımı, kimlik bilgilerinin çalınması ya da polisiye olaylara istemeden karışmak gibi sonuçlar doğurabilir.

Sohbet ve oyun odaları, çok güzel dostluklara ve ilişkilere vesile olabildiği gibi, hırsızlık, sübyancılık, teşhir, taciz, tecavüz ve hatta cinayete varan tehditlere de kapımızı sonuna kadar açmaktadır.

Pornografiye erişimin hızlı ve kolay olması, her yaşta pornografi bağımlılığı riskini artırmakta, şahısların cinsel hayatını, aile hayatını ve zaman zaman da psikolojilerini tehdit etmektedir. Çocukların çok küçük yaşta pornografiye kolayca erişebilmeleri, ileriki yaşlarda ciddi cinsel ve psikolojik rahatsızlıklara gebe olmalarına neden olabilmektedir.

Bu tehlikelerden korunma yöntemleri[değiştir | kaynağı değiştir]

İnternet ortamında kimliğini, yaşını, görünüşünü, ekonomik durumunu, eğitim durumunu, kısaca bir şahsa ait her şeyi gizlemek ya da sahte bir kimlik oluşturmak çok kolay olduğu için, arkadaşlık kurarken çok daha dikkatli olunması gerekir. Özellikle yeterince tanınmayan kişilere adres ve telefon vermekten özellikle kaçınılmalı, karşıdaki kişinin bunlara ulaşmasını sağlayacak ipuçları vermekten de sakınılmalıdır.

Günümüzde birçok İnternet güvenlik yazılımı, “ebeveyn kontrolü” özellikleri ile birlikte gelmektedir. Ebeveyn kontrol paneli bilgisayar erişim saatlerinin ayarlanmasına, istenmeyen sitelere erişimin engellenmesine imkân vermekte, bu ayarlar parolalar aracılığıyla korunabilmektedir.

Ayrıca bakınız[değiştir | kaynağı değiştir]

Kaynakça[değiştir | kaynağı değiştir]

  1. ^ a b Merriam Webster’s Dictionary & Thesaurus, 2008
  2. ^ TDK Türkçe Sözlük
  3. ^ “net.” Oxford Dictionary of English 2e, Oxford University Press, 2003.
  4. ^ “Internet.” Oxford Dictionary of English 2e, Oxford University Press, 2003.
  5. ^ http://www.emo.org.tr/ekler/951ccd95572a671_ek.doc?tipi=46&turu=X&sube=0

Dış bağlantılar[değiştir | kaynağı değiştir]