17
Android (operating system) 1 Android (operating system) Android Android 4.4 home screen Company / developer Google Open Handset Alliance Android Open Source Project (AOSP) Programmed in C (core), C++, Java (UI) OS family Unix-like Working state Current Source model Open source with proprietary components Initial release September 23, 2008 Latest stable release 4.4.2 KitKat / December 9, 2013 Marketing target Smartphones Tablet computers Available language(s) Multi-lingual (46 languages) Package manager Google Play, APK Supported platforms 32-bit ARM, MIPS, x86 Kernel type Monolithic (modified Linux kernel) Userland Bionic libc, [1] shell from NetBSD, [2] native core utilities with a few from NetBSD [3] Default user interface Graphical (Multi-touch) License Apache License 2.0 Linux kernel patches under GNU GPL v2 Official website www.android.com [4] Android is an operating system based on the Linux kernel, and designed primarily for touchscreen mobile devices such as smartphones and tablet computers. Initially developed by Android, Inc., which Google backed financially

Android (Operating System)

  • Upload
    skriikk

  • View
    94

  • Download
    2

Embed Size (px)

DESCRIPTION

Android (Operating System) Wiki

Citation preview

Page 1: Android (Operating System)

Android (operating system) 1

Android (operating system)

Android

Android 4.4 home screen

Company / developer GoogleOpen Handset AllianceAndroid Open Source Project (AOSP)

Programmed in C (core), C++, Java (UI)

OS family Unix-like

Working state Current

Source model Open source with proprietary components

Initial release September 23, 2008

Latest stable release 4.4.2 KitKat / December 9, 2013

Marketing target SmartphonesTablet computers

Available language(s) Multi-lingual (46 languages)

Package manager Google Play, APK

Supported platforms 32-bit ARM, MIPS, x86

Kernel type Monolithic (modified Linux kernel)

Userland Bionic libc,[1] shell from NetBSD,[2] native core utilities with a few from NetBSD[3]

Default user interface Graphical (Multi-touch)

License Apache License 2.0Linux kernel patches under GNU GPL v2

Official website www.android.com [4]

Android is an operating system based on the Linux kernel, and designed primarily for touchscreen mobile devices such as smartphones and tablet computers. Initially developed by Android, Inc., which Google backed financially

Page 2: Android (Operating System)

Android (operating system) 2

and later bought in 2005, Android was unveiled in 2007 along with the founding of the Open Handset Alliance: aconsortium of hardware, software, and telecommunication companies devoted to advancing open standards formobile devices. The first publicly available smartphone running Android, the HTC Dream, was released on October22, 2008.The user interface of Android is based on direct manipulation, using touch inputs that loosely correspond toreal-world actions, like swiping, tapping, pinching and reverse pinching to manipulate on-screen objects. Internalhardware such as accelerometers, gyroscopes and proximity sensors are used by some applications to respond toadditional user actions, for example adjusting the screen from portrait to landscape depending on how the device isoriented. Android allows users to customize their home screens with shortcuts to applications and widgets, whichallow users to display live content, such as emails and weather information, directly on the home screen.Applications can further send notifications to the user to inform them of relevant information, such as new emailsand text messages.Android is open source and Google releases the source code under the Apache License. This open-source code andpermissive licensing allows the software to be freely modified and distributed by device manufacturers, wirelesscarriers and enthusiast developers. In practice, Android devices ship with a combination of open source andproprietary software. Android has a large community of developers writing applications ("apps") that extend thefunctionality of devices, written primarily in the Java programming language. In October 2012, there wereapproximately 700,000 apps available for Android, and the estimated number of applications downloaded fromGoogle Play, Android's primary app store, was 25 billion. A developer survey conducted in April–May 2013 foundthat Android is the most popular platform for developers, used by 71% of the mobile developer population.[5]

Android is the world's most widely used smartphone platform, overtaking Symbian in the fourth quarter of 2010.Android is popular with technology companies who require a ready-made, low-cost, customizable and lightweightoperating system for high tech devices. Despite being primarily designed for phones and tablets, it also has beenused in televisions, games consoles, digital cameras and other electronics. Android's open nature has encouraged alarge community of developers and enthusiasts to use the open-source code as a foundation for community-drivenprojects, which add new features for advanced users or bring Android to devices which were officially releasedrunning other operating systems.As of November 2013[6], Android's share of the global smartphone market, led by Samsung products, has reached81%. The operating system's success has made it a target for patent litigation as part of the so-called "smartphonewars" between technology companies. As of May 2013[6], 48 billion apps have been installed from the Google Playstore, and as of September 2013[6], 1 billion Android devices have been activated.

HistoryAndroid, Inc. was founded in Palo Alto, California in October 2003 by Andy Rubin (co-founder of Danger), RichMiner (co-founder of Wildfire Communications, Inc.), Nick Sears (once VP at T-Mobile), and Chris White (headeddesign and interface development at WebTV) to develop, in Rubin's words "smarter mobile devices that are moreaware of its owner's location and preferences". The early intentions of the company were to develop an advancedoperating system for digital cameras, when it was realised that the market for the devices was not large enough, anddiverted their efforts to producing a smartphone operating system to rival those of Symbian and Windows Mobile.Despite the past accomplishments of the founders and early employees, Android Inc. operated secretly, revealingonly that it was working on software for mobile phones. That same year, Rubin ran out of money. Steve Perlman, aclose friend of Rubin, brought him $10,000 in cash in an envelope and refused a stake in the company.Google acquired Android Inc. on August 17, 2005; key employees of Android Inc., including Rubin, Miner and White, stayed at the company after the acquisition. Not much was known about Android Inc. at the time, but many assumed that Google was planning to enter the mobile phone market with this move. At Google, the team led by Rubin developed a mobile device platform powered by the Linux kernel. Google marketed the platform to handset

Page 3: Android (Operating System)

Android (operating system) 3

makers and carriers on the promise of providing a flexible, upgradable system. Google had lined up a series ofhardware component and software partners and signaled to carriers that it was open to various degrees of cooperationon their part.Speculation about Google's intention to enter the mobile communications market continued to build throughDecember 2006. The unveiling of the iPhone, a touchscreen-based phone by Apple, on January 9, 2007 had adisruptive effect on the development of Android. At the time, a prototype device codenamed "Sooner" had a closerresemblance to a BlackBerry phone, with no touchscreen, and a physical, QWERTY keyboard. Work immediatelybegan on re-engineering the OS and its prototypes to combine traits of their own designs with an overall experiencedesigned to compete with the iPhone. In September 2007, InformationWeek covered an Evalueserve study reportingthat Google had filed several patent applications in the area of mobile telephony.

Eric Schmidt, Andy Rubin and Hugo Barra at a press conference forthe Google's Nexus 7 tablet.

On November 5, 2007, the Open Handset Alliance, aconsortium of technology companies including Google,device manufacturers such as HTC, Sony andSamsung, wireless carriers such as Sprint Nextel andT-Mobile, and chipset makers such as Qualcomm andTexas Instruments, unveiled itself, with a goal todevelop open standards for mobile devices. That day,Android was unveiled as its first product, a mobiledevice platform built on the Linux kernel version 2.6.The first commercially available smartphone runningAndroid was the HTC Dream, released on October 22,2008.

In 2010, Google launched its Nexus series of devices — a line of smartphones and tablets running the Androidoperating system, and built by a manufacturer partner. HTC collaborated with Google to release the first Nexussmartphone, the Nexus One. The series has since been updated with newer devices, such as the Nexus 5 phone andNexus 7 tablet, made by LG and Asus respectively. Google releases the Nexus phones and tablets to act as theirflagship Android devices, demonstrating Android's latest software and hardware features. On March 13, 2013, it wasannounced by Larry Page in a blog post that Andy Rubin had moved from the Android division to take on newprojects at Google. He was replaced by Sundar Pichai, who also continues his role as the head of Google's Chromedivision, which develops Chrome OS.

Since 2008, Android has seen numerous updates which have incrementally improved the operating system, addingnew features and fixing bugs in previous releases. Each major release is named in alphabetical order after a dessert orsugary treat; for example, version 1.5 Cupcake was followed by 1.6 Donut. The latest released version is 4.4.2KitKat, which was released on 9 December 2013.

Page 4: Android (Operating System)

Android (operating system) 4

Features

Interface

Android green figure, next to its originalpackaging

Android's user interface is based on direct manipulation, using touchinputs that loosely correspond to real-world actions, like swiping,tapping, pinching and reverse pinching to manipulate on-screenobjects. The response to user input is designed to be immediate andprovides a fluid touch interface, often using the vibration capabilitiesof the device to provide haptic feedback to the user. Internal hardwaresuch as accelerometers, gyroscopes and proximity sensors are used bysome applications to respond to additional user actions, for exampleadjusting the screen from portrait to landscape depending on how thedevice is oriented, or allowing the user to steer a vehicle in a racinggame by rotating the device, simulating control of a steering wheel.

Android devices boot to the homescreen, the primary navigation and information point on the device, which issimilar to the desktop found on PCs. Android homescreens are typically made up of app icons and widgets; appicons launch the associated app, whereas widgets display live, auto-updating content such as the weather forecast,the user's email inbox, or a news ticker directly on the homescreen. A homescreen may be made up of several pagesthat the user can swipe back and forth between, though Android's homescreen interface is heavily customisable,allowing the user to adjust the look and feel of the device to their tastes. Third-party apps available on Google Playand other app stores can extensively re-theme the homescreen, and even mimic the look of other operating systems,such as Windows Phone. Most manufacturers, and some wireless carriers, customise the look and feel of theirAndroid devices to differentiate themselves from their competitors.Present along the top of the screen is a status bar, showing information about the device and its connectivity. Thisstatus bar can be "pulled" down to reveal a notification screen where apps display important information or updates,such as a newly received email or SMS text, in a way that does not immediately interrupt or inconvenience the user.In early versions of Android these notifications could be tapped to open the relevant app, but recent updates haveprovided enhanced functionality, such as the ability to call a number back directly from the missed call notificationwithout having to open the dialer app first. Notifications are persistent until read or dismissed by the user.

ApplicationsAndroid has a growing selection of third party applications, which can be acquired by users either through an appstore such as Google Play or the Amazon Appstore, or by downloading and installing the application's APK file froma third-party site. The Play Store application allows users to browse, download and update apps published by Googleand third-party developers, and is pre-installed on devices that comply with Google's compatibility requirements.The app filters the list of available applications to those that are compatible with the user's device, and developersmay restrict their applications to particular carriers or countries for business reasons. Purchases of unwantedapplications can be refunded within 15 minutes of the time of download, and some carriers offer direct carrier billingfor Google Play application purchases, where the cost of the application is added to the user's monthly bill.As of July 2013[6], there are more than one million applications available for Android in the Play Store. As of May2013[6], 48 billion apps have been installed from the Google Play store.Applications are developed in the Java language using the Android software development kit (SDK). The SDK includes a comprehensive set of development tools, including a debugger, software libraries, a handset emulator based on QEMU, documentation, sample code, and tutorials. The officially supported integrated development environment (IDE) is Eclipse using the Android Development Tools (ADT) plugin. Other development tools are

Page 5: Android (Operating System)

Android (operating system) 5

available, including a Native Development Kit for applications or extensions in C or C++, Google App Inventor, avisual environment for novice programmers, and various cross platform mobile web applications frameworks.In order to work around limitations on reaching Google services due to Internet censorship in the People's Republicof China, Android devices sold in the PRC are generally customized to use state approved services instead.[7]

Memory managementSince Android devices are usually battery-powered, Android is designed to manage memory (RAM) to keep powerconsumption at a minimum, in contrast to desktop operating systems which generally assume they are connected tounlimited mains electricity. When an Android app is no longer in use, the system will automatically suspend it inmemory – while the app is still technically "open", suspended apps consume no resources (e.g. battery power orprocessing power) and sit idly in the background until needed again. This has the dual benefit of increasing thegeneral responsiveness of Android devices, since apps don't need to be closed and reopened from scratch each time,but also ensuring background apps don't consume power needlessly.Android manages the apps stored in memory automatically: when memory is low, the system will begin killing appsand processes that have been inactive for a while, in reverse order since they were last used (i.e. oldest first). Thisprocess is designed to be invisible to the user, such that users do not need to manage memory or the killing of appsthemselves. However, confusion over Android memory management has resulted in third-party task killers becomingpopular on the Google Play store; these third-party task killers are generally regarded as doing more harm than good.

Hardware

Tronsmart MK908, a Rockchip-based quad-coreAndroid "mini PC", with a microSD card next to

it for a size comparison.

The main hardware platform for Android is the 32-bit ARMv7architecture. There is support for x86 from the Android-x86 project,and Google TV uses a special x86 version of Android. In 2013,Freescale announced Android on its i.MX processor, i.MX5X andi.MX6X series. In 2012 Intel processors began to appear on moremainstream Android platforms, such as phones.

As of November 2013, current versions of Android require at least512 MB of RAM, and a 32-bit ARMv7, MIPS or x86 architectureprocessor, together with an OpenGL ES 2.0 compatible graphicsprocessing unit (GPU). Android supports OpenGL ES 1.1, 2.0 and 3.0.Some applications explicitly require certain version of the OpenGL ES,thus suitable GPU hardware is required to run such applications.

Android devices incorporate many optional hardware components, including still or video cameras, GPS, hardwareorientation sensors, dedicated gaming controls, accelerometers, gyroscopes, barometers, magnetometers, proximitysensors, pressure sensors, thermometers and touchscreens. Some hardware components are not required, but becamestandard in certain classes of devices, such as smartphones, and additional requirements apply if they are present.Some other hardware was initially required, but those requirements have been relaxed or eliminated altogether. Forexample, as Android was developed initially as a phone OS, hardware such as microphones were required, whileover time the phone function became optional. Android used to require an autofocus camera, which was relaxed to afixed-focus camera if it is even present at all, since the camera was dropped as a requirement entirely when Androidstarted to be used on set-top boxes.

Page 6: Android (Operating System)

Android (operating system) 6

DevelopmentAndroid is developed in private by Google until the latest changes and updates are ready to be released, at whichpoint the source code is made available publicly.[8] This source code will only run without modification on selectdevices, usually the Nexus series of devices. The source code is, in turn, adapted by OEMs to run on their hardware.Android's source code does not contain the often proprietary device drivers that are needed for certain hardwarecomponents.The green Android logo was designed for Google in 2007 by graphic designer Irina Blok. The design team wastasked with a project to create a universally identifiable icon with the specific inclusion of a robot in the final design.After numerous design developments based on science-fiction and space movies, the team eventually soughtinspiration from the human symbol on restroom doors and modified the figure into a robot shape. As Android isopen-sourced, it was agreed that the logo should be likewise, and since its launch the green logo has beenreinterpreted into countless variations on the original design.

Update schedule

From left to right: HTC Dream (G1), Nexus One,Nexus S, Galaxy Nexus

Google provides major updates, incremental in nature, to Androidevery six to nine months, which most devices are capable ofreceiving over the air. The latest major update is Android 4.4KitKat.

Nexus 5, most recent smartphone in the Nexusrange

Compared to its chief rival mobile operating system, namely iOS,Android updates are typically slow to reach actual devices. For devicesnot under the Nexus brand, updates often arrive months from the timethe given version is officially released. This is caused partly due to theextensive variation in hardware of Android devices, to which eachupdate must be specifically tailored, as the official Google source codeonly runs on their flagship Nexus devices. Porting Android to specifichardware is a time- and resource-consuming process for devicemanufacturers, who prioritize their newest devices and often leaveolder ones behind. Hence, older smartphones are frequently notupdated if the manufacturer decides it is not worth their time,regardless of whether the phone is capable of running the update. Thisproblem is compounded when manufacturers customize Android withtheir own interface and apps, which must be reapplied to each newrelease. Additional delays can be introduced by wireless carriers who,after receiving updates from manufacturers, further customize andbrand Android to their needs and conduct extensive testing on theirnetworks before sending the update out to users.

Page 7: Android (Operating System)

Android (operating system) 7

The lack of after-sale support from manufacturers and carriers has been widely criticized by consumer groups andthe technology media. Some commentators have noted that the industry has a financial incentive not to update theirdevices, as the lack of updates for existing devices fuels the purchase of newer ones, an attitude described as"insulting". The Guardian has complained that the complicated method of distribution for updates is onlycomplicated because manufacturers and carriers have designed it that way. In 2011, Google partnered with a numberof industry players to announce an "Android Update Alliance", pledging to deliver timely updates for every devicefor 18 months after its release; however, this alliance has never been mentioned since.In 2012, Google began decoupling certain aspects of the operating system (particularly core applications) so theycould be updated through Google Play Store, independently of Android itself. One of these components, Google PlayServices, is a system-level process providing APIs for Google services, installed automatically on nearly all devicesrunning Android version 2.2 and higher. With these changes, Google can add new operating system functionalitythrough Play Services and application updates without having to distribute an update to the operating system itself.As a result, Android 4.2 and 4.3 contained relatively fewer user-facing changes, focusing more on minor changesand platform improvements.

Linux kernelAs of January 2014[6], current Android versions consist of a kernel based on the Linux kernel's longterm 3.4 branch,varying in version numbers depending on the actual Android device. Android versions older than 4.0 Ice CreamSandwich were based on the Linux kernel versions 2.6.x.Android's Linux kernel has further architecture changes by Google outside the typical Linux kernel developmentcycle. Certain features that Google contributed back to the Linux kernel, notably a power management feature called"wakelocks", were rejected by mainline kernel developers partly because they felt that Google did not show anyintent to maintain its own code. Google announced in April 2010 that they would hire two employees to work withthe Linux kernel community, but Greg Kroah-Hartman, the current Linux kernel maintainer for the stable branch,said in December 2010 that he was concerned that Google was no longer trying to get their code changes included inmainstream Linux. Some Google Android developers hinted that "the Android team was getting fed up with theprocess," because they were a small team and had more urgent work to do on Android.In August 2011, Linus Torvalds said that "eventually Android and Linux would come back to a common kernel, butit will probably not be for four to five years". In December 2011, Greg Kroah-Hartman announced the start of theAndroid Mainlining Project, which aims to put some Android drivers, patches and features back into the Linuxkernel, starting in Linux 3.3. Linux included the autosleep and wakelocks capabilities in the 3.5 kernel, after manyprevious attempts at merger. The interfaces are the same but the upstream Linux implementation allows for twodifferent suspend modes: to memory (the traditional suspend that Android uses), and to disk (hibernate, as it isknown on the desktop). Google maintains a public code repository that contains their experimental work to re-baseAndroid off the latest stable Linux versions.The flash storage on Android devices is split into several partitions, such as /system for the operating systemitself, and /data for user data and application installations. In contrast to desktop Linux distributions, Androiddevice owners are not given root access to the operating system and sensitive partitions such as /system areread-only. However, root access can be obtained by exploiting security flaws in Android, which is used frequentlyby the open-source community to enhance the capabilities of their devices,[9] but also by malicious parties to installviruses and malware.Android is a Linux distribution according to the Linux Foundation and Google's open-source chief, Chris DiBona.Others, such as Google engineer Patrick Brady, disagree that it is a Linux distribution, noting the lack of support formany GNU tools in Android, including glibc.

Page 8: Android (Operating System)

Android (operating system) 8

Software stack

Android's architecture diagram

On top of the Linux kernel, there arethe middleware, libraries and APIswritten in C, and application softwarerunning on an application frameworkwhich includes Java-compatiblelibraries based on Apache Harmony.Android uses the Dalvik virtualmachine with just-in-time compilationto run Dalvik "dex-code" (DalvikExecutable), which is usuallytranslated from the Java bytecode.Android 4.4 also supports newexperimental runtime virtual machine,ART, which is not enabled by default.

Android uses Bionic in place of astandard C library, originallydeveloped by Google specifically forAndroid, as a derivation of the BSD'sstandard C library code. Bionic has several major features specific to the Linux kernel, and its developmentcontinues independently of other Android's source code bases. The main benefits of using Bionic instead of the GNUC Library (glibc) or uClibc are its different licensing model, smaller runtime footprint, and optimization forlow-frequency CPUs.

Android does not have a native X Window System by default nor does it support the full set of standard GNUlibraries, and this makes it difficult to port existing Linux applications or libraries to Android. Support for simple Cand SDL applications is possible by injection of a small Java shim and usage of the JNI like, for example, in theJagged Alliance 2 port for Android.[10]

Open-source communityAndroid has an active community of developers and enthusiasts who use the Android Open Source Project (AOSP)source code to develop and distribute their own modified versions of the operating system. Thesecommunity-developed releases often bring new features and updates to devices faster than through the officialmanufacturer/carrier channels, albeit without as extensive testing or quality assurance; provide continued support forolder devices that no longer receive official updates; or bring Android to devices that were officially releasedrunning other operating systems, such as the HP TouchPad. Community releases often come pre-rooted and containmodifications unsuitable for non-technical users, such as the ability to overclock or over/undervolt the device'sprocessor. CyanogenMod is the most widely used community firmware, and acts as a foundation for numerousothers.Historically, device manufacturers and mobile carriers have typically been unsupportive of third-party firmware development. Manufacturers express concern about improper functioning of devices running unofficial software and the support costs resulting from this. Moreover, modified firmwares such as CyanogenMod sometimes offer features, such as tethering, for which carriers would otherwise charge a premium. As a result, technical obstacles including locked bootloaders and restricted access to root permissions are common in many devices. However, as community-developed software has grown more popular, and following a statement by the Librarian of Congress in the United States that permits the "jailbreaking" of mobile devices, manufacturers and carriers have softened their

Page 9: Android (Operating System)

Android (operating system) 9

position regarding third party development, with some, including HTC, Motorola, Samsung and Sony, providingsupport and encouraging development. As a result of this, over time the need to circumvent hardware restrictions toinstall unofficial firmware has lessened as an increasing number of devices are shipped with unlocked or unlockablebootloaders, similar to the Nexus series of phones, although usually requiring that users waive their devices'warranties to do so. However, despite manufacturer acceptance, some carriers in the US still require that phones arelocked down.The unlocking and "hackability" of smartphones and tablets remains a source of tension between the community andindustry, with the community arguing that unofficial development is increasingly important given the failure ofindustry to provide timely updates and/or continued support to their devices.

Security and privacy

Permissions are used to controla particular application's

access to system functions.

Android applications run in a sandbox, an isolated area of the system that does nothave access to the rest of the system's resources, unless access permissions areexplicitly granted by the user when the application is installed. Before installing anapplication, the Play Store displays all required permissions: a game may need toenable vibration or save data to an SD card, for example, but should not need to readSMS messages or access the phonebook. After reviewing these permissions, the usercan choose to accept or refuse them, installing the application only if they accept. Thesandboxing and permissions system lessens the impact of vulnerabilities and bugs inapplications, but developer confusion and limited documentation has resulted inapplications routinely requesting unnecessary permissions, reducing its effectiveness.Several security firms, such as Lookout Mobile Security, AVG Technologies, andMcAfee, have released antivirus software for Android devices. This software isineffective as sandboxing also applies to such applications, limiting their ability toscan the deeper system for threats.[11]

Research from security company Trend Micro lists premium service abuse as the most common type of Androidmalware, where text messages are sent from infected phones to premium-rate telephone numbers without the consentor even knowledge of the user. Other malware displays unwanted and intrusive adverts on the device, or sendspersonal information to unauthorised third parties. Security threats on Android are reportedly growing exponentially;however, Google engineers have argued that the malware and virus threat on Android is being exaggerated bysecurity companies for commercial reasons, and have accused the security industry of playing on fears to sell virusprotection software to users. Google maintains that dangerous malware is actually extremely rare, and a surveyconducted by F-Secure showed that only 0.5% of Android malware reported had come from the Google Play store.

Google currently uses their Google Bouncer malware scanner to watch over and scan the Google Play store apps. Itis intended to flag up suspicious apps and warn users of any potential issues with an application before theydownload it. Android version 4.2 Jelly Bean was released in 2012 with enhanced security features, including amalware scanner built into the system, which works in combination with Google Play but can scan apps installedfrom third party sources as well, and an alert system which notifies the user when an app tries to send apremium-rate text message, blocking the message unless the user explicitly authorises it.Android smartphones have the ability to report the location of Wi-Fi access points, encountered as phone users move around, to build databases containing the physical locations of hundreds of millions of such access points. These databases form electronic maps to locate smartphones, allowing them to run apps like Foursquare, Google Latitude, Facebook Places, and to deliver location-based ads. Third party monitoring software such as TaintDroid, an academic research-funded project, can, in some cases, detect when personal information is being sent from applications to remote servers. In August 2013, Google released the Android Device Manager (ADM), a component

Page 10: Android (Operating System)

Android (operating system) 10

that allows users to remotely track, locate, and wipe their Android device through a web interface. In December2013, Google released ADM as an Android application on the Google Play store, where it is available to devicesrunning Android version 2.2 and higher.The open-source nature of Android allows security contractors to take existing devices and adapt them for highlysecure uses. For example Samsung has worked with General Dynamics through their Open Kernel Labs acquisitionto rebuild Jelly Bean on top of their hardened microvisor for the "Knox" project.[12]

As part of the broader 2013 mass surveillance disclosures it was revealed in September 2013 that the American andBritish intelligence agencies, the NSA and Government Communications Headquarters (GCHQ) respectively, haveaccess to the user data on iPhone, BlackBerry, and Android devices. They are able to read almost all smartphoneinformation, including SMS, location, emails, and notes.

LicensingThe source code for Android is available under free and open-source software licenses. Google publishes most of thecode (including network and telephony stacks) under the Apache License version 2.0, and the rest, Linux kernelchanges, under the GNU General Public License version 2. The Open Handset Alliance develops the changes to theLinux kernel, in public, with source code publicly available at all times. The rest of Android is developed in privateby Google, with source code released publicly when a new version is released. Typically Google collaborates with ahardware manufacturer to produce a "flagship" device (part of the Nexus series) featuring the new version ofAndroid, then makes the source code available after that device has been released. The only Android release whichwas not immediately made available as source code was the tablet-only 3.0 Honeycomb release. The reason,according to Andy Rubin in an official Android blog post, was because Honeycomb was rushed for production of theMotorola Xoom, and they did not want third parties creating a "really bad user experience" by attempting to put ontosmartphones a version of Android intended for tablets.While much of Android itself is open source software, most Android devices ship with a large amount of proprietarysoftware. Google licenses a suite of proprietary apps for Android, such as Play Store, Google Search, and GooglePlay Services—a software layer which provides APIs that integrate with Google-provided services, among others.These apps, along with the Android trademarks, can only be licensed by hardware manufacturers for devices thatmeet Google's compatibility standards; as such, forks of Android that make major changes to the OS itself, such asAmazon's Fire OS and Alibaba Group's Aliyun OS, do not include any of Google's non-free components, and areincompatible with apps that require them. Custom, certified distributions of Android produced by manufacturers(such as TouchWiz and HTC Sense) may also replace certain stock Android apps with their own proprietary variantsand add additional software not included in the stock Android operating system. With many devices, there are binaryblobs that must be provided by the manufacturer in order for Android to work. Also, device manufacturers cannotuse Google's Android trademark unless Google certifies that the device complies with their Compatibility DefinitionDocument (CDD).Several stock apps in Android's open source code used by previous versions (such as Search, Music, and Calendar)have also been effectively deprecated by Google, with development having shifted to newer but proprietary versionsdistributed and updated through Play Store, such as Google Search and Google Play Music. While these older appsremain in Android's source code, they have no longer received any major updates. Additionally, proprietary variantsof the stock Camera and Gallery apps also include certain functions (such as Photosphere panoramas and Google+album integration) that are excluded from the open source versions (however, they have yet to be completelyabandoned), and the home screen itself on the Nexus 5 is replaced by one implemented as a component of theproprietary Google Search app. Although an update for Google Search containing the relevant components wasreleased through Google Play for all Android devices, the new home screen was not enabled by the Android 4.4updates for any other Nexus devices, which still use the previous AOSP home screen.

Page 11: Android (Operating System)

Android (operating system) 11

Richard Stallman and the Free Software Foundation have been critical of Android and have recommended the usageof alternatives such as Replicant, because drivers and firmware vital for the proper functioning of Android devicesare usually proprietary, and because Google Play allows non-free software.

Reception

Android-x86 running on an ASUS EeePCnetbook; Android has been unofficially ported togeneric computers for use as a desktop operating

system.

Android received a lukewarm reaction when it was unveiled in 2007.Although analysts were impressed with the respected technologycompanies that had partnered with Google to form the Open HandsetAlliance, it was unclear whether mobile phone manufacturers would bewilling to replace their existing operating systems with Android. Theidea of an open-source, Linux-based development platform sparkedinterest, but there were additional worries about Android facing strongcompetition from established players in the smartphone market, suchas Nokia and Microsoft, and rival Linux mobile operating systems thatwere in development. These established players were skeptical: Nokiawas quoted as saying "we don't see this as a threat," and a member ofMicrosoft's Windows Mobile team stated "I don't understand theimpact that they are going to have."

Since then Android has grown to become the most widely used smartphone operating system and "one of the fastestmobile experiences available." Reviewers have highlighted the open-source nature of the operating system as one ofits defining strengths, allowing companies such as Amazon (Kindle Fire), Barnes & Noble (Nook), Ouya, Baidu andothers to fork the software and release hardware running their own customised version of Android. As a result, it hasbeen described by technology website Ars Technica as "practically the default operating system for launching newhardware" for companies without their own mobile platforms. This openness and flexibility is also present at thelevel of the end user: Android allows extensive customisation of devices by their owners and apps are freelyavailable from non-Google app stores and third party websites. These have been cited as among the main advantagesof Android phones over others.

Despite Android's popularity, including an activation rate three times that of iOS, there have been reports thatGoogle has not been able to leverage their other products and web services successfully to turn Android into themoney maker that analysts had expected. The Verge suggested that Google is losing control of Android due to theextensive customization and proliferation of non-Google apps and services—Amazon's Kindle Fire line uses FireOS, a heavily modified fork of Android which does not include or support any of Google's proprietary components,and requires that users obtain software from its competing Amazon Appstore instead of Play Store. Google SVPAndy Rubin, who was replaced as head of the Android division in March 2013, has been blamed for failing toestablish a lucrative partnership with cell phone makers. The chief beneficiary of Android has been Samsung, whoseGalaxy brand has surpassed that of Android in terms of brand recognition since 2011. Meanwhile other Androidmanufacturers have struggled since 2011, such as LG, HTC, and Google's own Motorola Mobility (whosepartnership with Verizon Wireless to push the "DROID" brand has faded since 2010). Ironically, while Googledirectly earns nothing from the sale of each Android device, Microsoft and Apple have successfully sued to extractpatent royalty payments from Android handset manufacturers.Android has suffered from "fragmentation", a situation where the variety of Android devices, in terms of both hardware variations and differences in the software running on them, makes the task of developing applications that work consistently across the ecosystem harder than rival platforms such as iOS where hardware and software varies less. For example, according to data from OpenSignal in July 2013, there were 11,868 models of Android device, numerous different screen sizes and eight Android OS versions simultaneously in use, while the large majority of

Page 12: Android (Operating System)

Android (operating system) 12

iOS users have upgraded to the latest iteration of that OS. Critics such as Apple Insider have asserted thatfragmentation via hardware and software pushed Android's growth through large volumes of low end, budget-priceddevices running older versions of Android. They maintain this forces Android developers to write for the "lowestcommon denominator" to reach as many users as possible, who have too little incentive to make use of the latesthardware or software features only available on a smaller percentage of devices. However, OpenSignal, whodevelops both Android and iOS apps, concluded that although fragmentation can make development trickier,Android's wider global reach also increases the potential reward.

Tablets

The first-generation Nexus 7 tablet

Despite its success on smartphones, initially Android tablet adoptionwas slow. One of the main causes was the chicken or the egg situationwhere consumers were hesitant to buy an Android tablet due to a lackof high quality tablet apps, but developers were hesitant to spend timeand resources developing tablet apps until there was a significantmarket for them. The content and app "ecosystem" proved moreimportant than hardware specs as the selling point for tablets. Due tothe lack of Android tablet-specific apps in 2011, early Android tabletshad to make do with existing smartphone apps that were ill-suited tolarger screen sizes, whereas the dominance of Apple's iPad wasreinforced by the large number of tablet-specific iOS apps.[13]

Despite app support in its infancy, a considerable number of Androidtablets (alongside those using other operating systems, such as the HPTouchPad and BlackBerry PlayBook) were rushed out to market in anattempt to capitalize on the success of the iPad. InfoWorld hassuggested that some Android manufacturers initially treated their firsttablets as a "Frankenphone business", a short-term low-investmentopportunity by placing a smartphone-optimized Android OS (beforeAndroid 3.0 Honeycomb for tablets was available) on a device whileneglecting user interface. This approach, such as with the Dell Streak, failed to gain market traction with consumersas well as damaging the early reputation of Android tablets. Furthermore, several Android tablets such as theMotorola Xoom were priced the same or higher than the iPad, which hurt sales. An exception was the AmazonKindle Fire, which relied upon lower pricing as well as access to Amazon's ecosystem of apps and content.

This began to change in 2012 with the release of the affordable Nexus 7 and a push by Google for developers towrite better tablet apps. Android tablet market share surpassed the iPad's in Q3 2012.

Market shareResearch company Canalys estimated in the second quarter of 2009 that Android had a 2.8% share of worldwidesmartphone shipments. By the fourth quarter of 2010 this had grown to 33% of the market, becoming the top-sellingsmartphone platform. By the third quarter of 2011 Gartner estimated that more than half (52.5%) of the smartphonemarket belongs to Android. By the third quarter of 2012 Android had a 75% share of the global smartphone marketaccording to the research firm IDC.In July 2011, Google said that 550,000 new Android devices were being activated every day, up from 400,000 perday in May, and more than 100 million devices had been activated with 4.4% growth per week. In September 2012,500 million devices had been activated with 1.3 million activations per day. In May 2013, at Google I/O, SundarPichai announced that 900 million Android devices had been activated.

Page 13: Android (Operating System)

Android (operating system) 13

Android market share varies by location. In July 2012, Android's market share in the United States was 52%, androse to 90% in China. During the third quarter of 2012, Android's worldwide smartphone market share was 75%,with 750 million devices activated in total and 1.5 million activations per day.As of March 2013, Android's share of the global smartphone market, led by Samsung products, was 64%. TheKantar market research company reported that Google’s platform accounted for over 70% of all smartphone devicesales in China during this period and that Samsung's loyalty rate in Britain (59%) is second to that of Apple (79%).As of November 2013, Android's share of the smartphone market is said to have reached 80%. Indeed, duringAugust, September, and October 2013, no less than 261.1 million smartphones were sold overall, with about 211million smartphones running Google's operating system.[]

Platform usage

Breakdown of the Android versions usage

These charts provide data about therelative number of devices accessingthe Play Store recently and running agiven version of the Android platform,as of 11 January 2014.

Version Code name Release date API level Distribution

4.4 KitKat October 31, 2013 19 1.4%

4.3.x Jelly Bean July 24, 2013 18 7.8%

4.2.x November 13, 2012 17 15.4%

4.1.x July 9, 2012 16 35.9%

4.0.3–4.0.4 Ice Cream Sandwich December 16, 2011 15 16.9%

3.2 Honeycomb July 15, 2011 13 0.1%

2.3.3–2.3.7 Gingerbread February 9, 2011 10 21.2%

2.2 Froyo May 20, 2010 8 1.3%

Application piracyThere has been some concern about the ease with which paid Android apps can be pirated. In a May 2012 interviewwith Eurogamer, the developers of Football Manager stated that the ratio of pirated players vs legitimate players was9:1 for their game Football Manager Handheld. However, not every developer agreed that piracy rates were an issue;for example, in July 2012 the developers of the game Wind-up Knight said that piracy levels of their game were only12%, and most of the piracy came from China, where people cannot purchase apps from Google Play.In 2010, Google released a tool for validating authorized purchases for use within apps, but developers complained that this was insufficient and trivial to crack. Google responded that the tool, especially its initial release, was intended as a sample framework for developers to modify and build upon depending on their needs, not as a finished

Page 14: Android (Operating System)

Android (operating system) 14

piracy solution. In 2012 Google released a feature in Android 4.1 that encrypted paid applications so that they wouldonly work on the device on which they were purchased, but this feature has been temporarily deactivated due totechnical issues.

Legal issuesBoth Android and Android phone manufacturers have been involved in numerous patent lawsuits. On August 12,2010, Oracle sued Google over claimed infringement of copyrights and patents related to the Java programminglanguage. Oracle originally sought damages up to $6.1 billion, but this valuation was rejected by a United Statesfederal judge who asked Oracle to revise the estimate. In response, Google submitted multiple lines of defense,counterclaiming that Android did not infringe on Oracle's patents or copyright, that Oracle's patents were invalid,and several other defenses. They said that Android is based on Apache Harmony, a clean room implementation ofthe Java class libraries, and an independently developed virtual machine called Dalvik. In May 2012, the jury in thiscase found that Google did not infringe on Oracle's patents, and the trial judge ruled that the structure of the JavaAPIs used by Google was not copyrightable.In addition to lawsuits against Google directly, various proxy wars have been waged against Android indirectly bytargeting manufacturers of Android devices, with the effect of discouraging manufacturers from adopting theplatform by increasing the costs of bringing an Android device to market. Both Apple and Microsoft have suedseveral manufacturers for patent infringement, with Apple's ongoing legal action against Samsung being aparticularly high-profile case. In October 2011, Microsoft said they had signed patent license agreements with tenAndroid device manufacturers, whose products account for 55% of the worldwide revenue for Android devices.These include Samsung and HTC. Samsung's patent settlement with Microsoft includes an agreement that Samsungwill allocate more resources to developing and marketing phones running Microsoft's Windows Phone operatingsystem.Google has publicly expressed its frustration for the current patent landscape in the United States, accusing Apple,Oracle and Microsoft of trying to take down Android through patent litigation, rather than innovating and competingwith better products and services. In 2011–12, Google purchased Motorola Mobility for US$12.5 billion, which wasviewed in part as a defensive measure to protect Android, since Motorola Mobility held more than 17,000 patents. InDecember 2011, Google bought over a thousand patents from IBM.In 2013, Fairsearch, a lobbying organization supported by Microsoft, Oracle and others, filed a complaint regardingAndroid with the European Commission, alleging that its free of charge distribution model constitutedanti-competitive predatory pricing. The Free Software Foundation Europe, whose donors include Google, disputedthe Fairsearch allegations.

Usage on other devices

Ouya, a video game console which runs Android,was one of the most successful crowdfunding

campaigns on the website Kickstarter.

The open and customizable nature of Android allows it to be used onother electronics aside from smartphones and tablets, including laptopsand netbooks, smartbooks, smart TVs (Google TV) and cameras(Nikon Coolpix S800c and Galaxy Camera). In addition, the Androidoperating system has seen applications on smart glasses (GoogleGlass), smartwatches, headphones, car CD and DVD players, mirrors,portable media players, landline and Voice over IP phones. Ouya, avideo game console running Android, became one of the mostsuccessful Kickstarter campaigns, crowdfunding US$8.5m for its

Page 15: Android (Operating System)

Android (operating system) 15

development, and was later followed by other Android-based consoles, such as Nvidia's Project Shield — anAndroid device in a video game controller form factor.In 2011, Google demonstrated "Android@Home", a home automation technology which uses Android to control arange of household devices including light switches, power sockets and thermostats. Prototype light bulbs wereannounced that could be controlled from an Android phone or tablet, but Android head Andy Rubin was cautious tonote that "turning a lightbulb on and off is nothing new", pointing to numerous failed home automation services.Google, he said, was thinking more ambitiously and the intention was to use their position as a cloud servicesprovider to bring Google products into customers' homes.[14]

In August 2011, Parrot launched the first car stereo system powered by the Android platform, known as Asteroid andfeaturing voice commands. In September 2013, Clarion released more advanced car stereo systems powered by theAndroid platform, known as AX1 and Mirage, running Android 2.3.7 and 2.2 (Gingerbread), respectively, andfeaturing GPS-based navigation, 6.5-inch screen and various options for wireless data access.

References[1] android/platform/bionic/ (https:/ / android. googlesource. com/ platform/ bionic/ + / master/ libc/ )[2] android/platform/system/core/sh/ (https:/ / android. googlesource. com/ platform/ system/ core/ + / master/ sh/ )[3] android/platform/system/core/toolbox/ (https:/ / android. googlesource. com/ platform/ system/ core/ + / master/ toolbox/ )[4] http:/ / www. android. com/[5] Developer Economics Q3 2013 analyst report – http:/ / www. visionmobile. com/ DevEcon3Q13 – Retrieved July 2013[6] http:/ / en. wikipedia. org/ w/ index. php?title=Android_(operating_system)& action=edit[7] Yun Qing, Liau. "Phonemakers make Android China-friendly." (http:/ / www. zdnet. com/ cn/

phonemakers-make-android-china-friendly-7000005679/ ) ZD Net, October 15, 2012.[8] At http:/ / source. android. com[9] See rooting[10] JA2 Stracciatella Feedback » Jagged Alliance 2 Android Stracciatella Port RC2 Release – please test (http:/ / www. ja-galaxy-forum. com/

board/ ubbthreads. php?ubb=showflat& Number=273148& page=1) on the Bear's Pit Forum, October 3, 2011[11] http:/ / www. extremetech. com/ computing/ 104827-android-antivirus-apps-are-useless-heres-what-to-do-instead/ 2 Android antivirus apps

are useless, here's what to do instead — access April 10, 2012[12] "Samsung Armors Android to Take On BlackBerry." (http:/ / www. nytimes. com/ 2013/ 02/ 28/ technology/

samsung-armors-android-to-take-on-blackberry. html)

• Damon Poeter (December 27, 2012) "Non-Apple Tablets Making Small Gains on iPad" PC Magazine (http:/ / www. pcmag. com/ article2/0,2817,2413605,00. asp)

• Matt Hartley (December 24 2011) "Massacre of the Tablets" Financial Post (http:/ / business. financialpost. com/ 2011/ 12/ 24/massacre-of-the-tablets/ )

[14] Why the time has come for Android @Home to finally make a splash by Janko Roettgers (http:/ / gigaom. com/ 2013/ 05/ 07/why-the-time-has-come-for-android-home-to-finally-make-a-splash/ )

External links• Official website (http:/ / www. android. com/ )• Sergey Brin introduces the Android platform (https:/ / www. youtube. com/ watch?v=1FJHYqE0RDg) on

YouTube

Page 16: Android (Operating System)

Article Sources and Contributors 16

Article Sources and ContributorsAndroid (operating system)  Source: http://en.wikipedia.org/w/index.php?oldid=591706491  Contributors: 12visakhva, 336, 51kwad, 777sms, 842U, 9th jinchuriki, A bit iffy, A.sutton, A412, A520, A5b, A665321, Aadadurov, Aalok.sathe, Abhishek191288, Abhishekitmbm, Abledsoe78, Abrahami, AbstractClass, Acalamari, Aceleo, Acery, Adambiswanger1, Adamjacobd, Adamwatters, Adi19956, Adileader, AdjustablePliers, Adm.Wiggin, Adnan.jsr, Afriza, Aftekology, Aftershave, Agentlame, Akbarzpro, Akshayjain123, AladdinSE, Albert Lee1, Alboran, Alejo2083, Alex, AlexKucherenko, AlexMS, Alexey Izbyshev, Alexius08, Alfasst, Alfredo ougaowen, Alfstar1997, Algedrez609, Ali'i, Aliendude5300, Alisha.4m, AlistairMcMillan, Allen Moore, Allstarecho, Alphaaslam, Alphius, Alunphillips, Alvestrand, Amarenderjannu, Amatulic, Ambictus, Amckern, Ameliorate!, Amy Ratcliffe, Ancheta Wis, Andareed, Anderssl, Andreas Bischoff, Andreas Carter, Andrejavus, Andresfi, Andrew Delong, AndrewHowse, Andrewkantor, Android4.0, Androidliscence, Androidmids, AndyTheGrump, Andyjsmith, Angstygangsta, Anindya Bakshi, Ankitasdeveloper, AnonMoos, Anoopan, Anoopmichael, Anthonyhcole, Anthonynon, Antnee, Anton.akhmerov, Anupamcin, Aoeuser, Aoidh, Apobilgin, Aquarat, Aradius, Arancı, Arc Orion, Arcanis, Archangelsk, ArgetlahmSource, Arghya139, Arichnad, Arjun G. Menon, ArjunTemurnikano, Armunalam, Arthas01, Aryamanjain, Aryndar, Ash Crow, Ashishjain999, Ashwin18, Aspensti, Astonmartini, Asymmetric, Athzai Khaine, Atlantia, AtteL, Attilios, Audi152, Audriusa, Automate, AwamerT, AwesomeSaucer9, Axl, Ayd00, Ayd000, Ayd86, Aydceri, Aydcery00, Aydcery86, Aydchery00, Aydin00, Azza-bazoo, BD2412, BY.Apps, Back ache, Bagelfat101010, Bahua, Bangbang.S, Banksbr2, Barek, Baronnet, Barte, Bayonetblaha, Bbaumer, Bbisgard, Bdesham, Bearda, Bedna, Beland, Belunga40, Ben Tillman, Bender235, Benjaminb, Benlisquare, Berelv, Betmenko, Bevo, Bgwhite, Bhny, Biker Biker, Bilbo571, Bill william compton, Binarybits, Bios Element, Blackfireshocker, Blahbabe61, Blethering Scot, Blindwaves, Blogfactor, Bloggus1225, Blowdart, Bomazi, Bonadea, Bongwarrior, Boo14940, Bosqueschool, Bovineone, Bpave777, Brandorr, Brettchawkins, Brianreading, Brianski, Briantist, Bryan.burgers, BucsWeb, Bungalowbill, Bweono, C.Logan, C628, CCalo, CJLL Wright, CJMiller, CPGustafson511, CRGreathouse, CTF83!, Cacophony, Caltas, Calvinst, Can't sleep, clown will eat me, Capouch, Captpossum, CaribDigita, Carlton.northern, Carrlos, CaseyBorders, CastAStone, Causa sui, Cbmaster, Cbr1000f, Cburnett, Cgtdk, Ch Th Jo, Chainz, Chancer1001, ChaosData, Chardot, [email protected], CharlesC, Cheekeong123, Cherie327, Cherkash, Chezi-Schlaff, Chicago brian, Chiles Malesters, Chillpenguin, Chillum, Chirags, Chr1syr, Chris Bainbridge, Chris the speller, Chris.p.wu, ChrisHeller, ChrisfromHouston, Chrismiceli, Chrispilot2293, Christian75, Ciphergoth, Ciphers, Claratte, ClaudeReigns, Clovis Sangrail, Codename Lisa, Coffee, Colonies Chris, CommonsDelinker, Comp.arch, Compfreak7, ComputerGeek706, Conan, Conquerist, Conti, Conzorz, Coolbho3000, Coolstoryhansel, CoordinateFreak, Cootiequits, Corevette, Cornlad, Costa Discordia, Count Chockula, Cpl Syx, CrabbyPatrick, Crackerspeanut12, Craigbarnes85, Craigbrass, Cresdajv, Cruiserbmw, Crysb, Csrempert, Cybercobra, Cyrotux, Czarkoff, D-Notice, D20sheets, DGMDGM, DHN, DPRoberts534, DStoykov, DVdm, Daabomb, Daev, Dagelf, Dale Arnett, Dancter, Dandyandroid, Danger, Daniel.Cardenas, DanielPharos, Dano55555, Danrok, DarTar, Daranz, Dark-Fire, Darkspy945, DarrenW, Darrenm540, David Edgar, David Gerard, David Hedlund, David Woodward, Davidhorman, Dawnseeker2000, Dbachmann, Dcxf, Deattitude, Decode, Degorr, Demysc, Denniss, Dennisthe2, Desbest, Dgw, Dhaluza, Diamondland, Diannaa, Diblidabliduu, Diego Moya, Diego.viola, Digana, Digilee, Dikaalnas, Dingar, Dismas, Dj.cowan, Dlrohrer2003, Dmit, DmitryKo, Docu, Donmike10, Donner60, Dontmitchell, Douglaswth, Download, Dpupkov, Dr.Soft, Dra.vladvamp, DragonLord, Drbreznjev, Dreaded Walrus, Drmonocle, Drogonov, Drrll, Dsh13, Dsimic, Dsrivallabha, Dstruct2k, DudeThinking, Dudyk, Dueynz, DuhAmericanDream, Dusti, Dvyjones, Dziedrius, E258, E2eamon, EEMIV, ESkog, Eaefremov, EagerToddler39, Eagle-slayor, Eapache, Ebe123, Echeese, Eciepecie, Ed Burnette, Ed Poor, EdBever, Edoe, Edward, Ej159, Ekerazha, Electricmuffin11, ElectroPro, Electron9, Elektron, Eleman, ElfMage, Elronxenu, Emurphy42, EngineerFromVega, Enigmaticland, Ennustaja, Eno, EonOmega, Epicgenius, Erc, Eric 324, ErkinBatu, Erwin Mulialim, Esebi95, Espertus, Essayemyoung4009, Estemi, Ettrig, EugeneKay, Eugrus, Excirial, Exien, Explorer25, Faddykeyboard, Fanatic.manav, Fangfufu, Fastily, FatalError, Fattmann, Favonian, Fbarousse, Fbtjock, Feedmecereal, Ferengi, Feudonym, Ffinder, Filmore, Finalius, Firefoxian, Fish and karate, Fjmustak, Flatterworld, Fleminra, FlieGerFaUstMe262, Flintb, Floating Boat, Flohack, Fluffylouis, Fly fly fly, Found5dollar, Fox hyx, Fraggle81, Fran Rogers, Frankie, Frap, FredTubale, Freddicus, Free French, Freebiekr, Friginator, Frmorrison, Frood, Fryn, Fsamuels, Funandtrvl, FurrySings, Furrykef, Fxhomie, G&CP, GJB 70, Gabriel A. Zorrilla, Gainesk, Gaius Cornelius, Galaxytab, Gallagher783, Games Yes!, Gareth E Kegg, Gareth Griffith-Jones, Gary King, Gautamkishore, Gboxdance, Gchangetok, Gdm, Geary, Gegorg, George Ponderevo, Gerhman, Gh5046, Ghepeu, Ghettoblaster, Ghost650, GioGziro95, Giraffedata, Glany222, GlasGhost, GlassCobra, Glen 3B, Goa103, Gogo Dodo, Gogoloid, GoingBatty, Gokberks, Gokul.gk7, GoldKanga, Golftheman, Gooberfox, Good Olfactory, Googlemobileplatform, Googlesubculture, Gopi.satya, Gordon Ecker, GorillaWarfare, Gouranga Gupta, Gourinath, GraemeL, Grafen, Graft, Graham87, Graig123, Grandscribe, Granty24, GreenpeaceUbuntuMan, Greenrd, Gregconquest, Grika, Gronky, Grshiplett, Gsarwa, Gscshoyru, Gsonnenf, Gu1dry, Gudeldar, Gugu2903, Guitarguy99081, Gurch, Guru4321, Guyjohnston, Guzzyron, Gyro Copter, Götz, H4lfN3ls0n, HJ Mitchell, Haakon, Hacheema, Haeinous, Haggisfarm, Hammersoft, Hanamanteo, Hanifbbz, Hannes1983, HardCorwen, Harimohan07, Harizotoh9, Harp, Haseo9999, Hateman20, Hcaandersen, Hcobb, Headinthedoor, Hedge777, Hellclanner, Henriok, Henry W. Schmitt, Herakleitoszefesu, Hervegirod, Hgb asicwizard, Himanis Das, Hockeyc, Hominid, Honeymanl, Hoss789, HotXRock, Hotcrocodile, Howlingmadhowie, Htchien, Htinlinn90, Hu12, Hucz, Hughcharlesparker, Hugo 87, Huku-chan, Hutchinsonam, Hvn0413, Hydarnes, Hydrox, Hymek, I Feel Tired, I, Podius, I5bala, IBoy2G, IGEL, IRWolfie-, ISTB351, Ian1337, IceHunter, Icep, Icydesign, Iggymwangi, Ijon, Iknowyourider, IlPisano, Illegal Operation, Imagine Reason, Immunmotbluescreen, Imroy, Indianstar, InternetMeme, Invenio, InverseHypercube, InvertedPendulum, Ionistii, Iridescent, Irishguy, Irislia, Ironmagma, Isaacwaller, Isacdaavid, Island Monkey, Itsmeard, Iuhkjhk87y678, Ivant, Ivario, J.delanoy, JAMJAM1666, JCDenton2052, JEN9841, JHunterJ, JLMCGE01, JRHorse, Jabberwoch, Jack Greenmaven, Jack007, Jackmcbarn, Jacob Poon, Jacob Steven Smith, JacobSheehy, Jacobmathias, Jadden14, Jairodz, Jaizovic, Jalabi99, Jamadagni, James Foster, JamesBWatson, JamesNBarnes, Jamesmcmahon0, Jamgraham88, Jamougha, Jarble, JaredMT, JasonS2101, Jasper Deng, Javachan, JavierCane, JavierMC, Javierito92, Jayant2164, Jb0807, Jboyens, Jbreckenridge, Jcogbil, Jdthood, JeR, Jeff G., Jeffq, Jeffrey Sharkey, Jeffwang, Jenova20, Jenskristian, Jerebin, JeremyA, Jerome Charles Potts, Jeromeds99, Jerrinsg, Jerryobject, Jesant13, Jessica23, Jeysaba, Jfayel, Jhonnyx1000, Jiess, Jim1138, Jimmin, Jimthing, Jimv1983, Jinmyo, Jlav78, Jmcdon10, Jmecimore, Joancdocyogen, JobiWan144, Joconnor, Joe Sewell, Joe2832, Joeblow398847232, Joeinwap, Joemalt1832, Joepearson, Johantheghost, John Ericson, JohnSawyer, Johnathe, Johnconorryan, Johndburger, JohnnotJon, Jokonek, Jonabbey, Jonathan-Morris711, JonathonSimister, Jonhope123, Jonkerz, Jontintinjordan, Jopo, Jordi Burguet Castell, Jorge Stolfi, Joriki, JosJuice, JoseREMY, Josh.e.stroud, JoshDuffMan, Jpvinall, Jreferee, Jrishel, Jtalledo, Jtangsw, Jtfcobra, Jubeidono, Julesd, Jurisnipper, Jusses2, Justin.Parallax, Jvosika, Jwkilgore, KAMiKAZOW, KSEltar, Kaicarver, Kaisersushi, Karam.Anthony.K, Karthickmad, Katherine, Katoh, Kawasakik, KayoWikiP069, KenSharp, Kenneth Gershom, Kenny Strawn, Kentyman, Kepwick, Keshava G N, Kevin James Field, Kevin3179, Kevthegreat55, Kforeman1, Khalid hassani, Khanayub1986, Khr0n0s, Kiddington, Kien64, KimDabelsteinPetersen, King Arthur6687, Kingdowney, Kingpin13, Kinkate18nic, Kiore, Kitsunegami, Kkm010, Klemen Kocjancic, Klingoncowboy4, Kmdowns, Knud Winckelmann, Koavf, Kokken Tor, Koman90, Komitsuki, Kontar, Korkut00, Korkut000, Kozuch, Kraaghavin, Kraftlos, Krazywrath, Krc1185, Kris cs1, Kronox android, Krushia, Ksyrie, Ktlynch, KumardipSarkar, Kungming2, Kushal one, Kwamikagami, Kylelnny, Kylesamani, L.tak, LSUniverse, Labalius, LafinJack, LancerEvolution ;, Lanilsson, Larrymcp, Larryn1030, LarsHolmberg, LarsPensjo, Lbstone27, Ldfleur, Legnaw, Legoboy920, Lenar, Lesmin, Lester, Lethe, Leuk he, Leuko, Levineps, Lexischemen, Lfcohen, Libcub, LightSpeed3, Lightenoughtotravel, Lightmouse, Limefrost Spiral, Lindamilton, Lindberg, LinuxOne, Ljfeliu, Lkt1126, Llancast, Llewelyn MT, Logan, Logical Cowboy, Lokpest, Lolametro, Longhornkate, LookingGlass, Lopifalko, LorenzoB, Lotje, Lovetinkle, Lucas.Yamanishi, Luckerr, Lukini, Lun Esex, M0sia1, MER-C, MKar, MZMcBride, Mac, Macungie, Madeincat, Magioladitis, Mahanga, Male1979, Manop, Mantrik00, Mappum, Marc Lacoste, Marc44, Marcus Brute, Marcus Qwertyus, Marcus2020, Marcuslim, Mardus, Marek69, Mark Renier, Mark0528, Markmcwiggins, Marko Gargenta, Markpb91, Marksagent, Marksbark, Marqueed, Martarius, Martin.komunide.com, Mastrsushi, Materialscientist, Mathewsherdil, Matt Darby, Matthew0028, MatthewBurton, MattieTK, Mattkap, Mattkap2, Maulikdave05, Maurice Carbonaro, Mauripop, Maxdeutc, Maxime Caudebec, Maximus06, Maxviwe, Maxí, McGeddon, Mcld, Mdikici, Mdy66, Meepzip, Meersmaj, Melab-1, Melizg, Melmann, Melonkelon, Mendaliv, Mentifisto, Messiisking, MetaManFromTomorrow, Mewtu, Mharen, Michaelplourde66, Midgetman433, Mikael Häggström, Mike Rosoft, Mike.lifeguard, Milan Keršláger, Mild Bill Hiccup, Millstream3, Miltonhowe, Mimihitam, Mindmatrix, Minterior, Mirabilos, Mirko Raner, Miserlou, Mistral Mktg, Mistral Solutions, Mkouklis, Mobilecushion, Mobilepush, Modamoda, Moe Epsilon, Mogism, Mohanpram, Mohit kesarwani, Moneytoo, Moocha, Mordka, MoreNet, MoreThings, Morian27, Morning277, Mortense, Moshi Monster Fan303, Mr Stephen, Mr. Met 13, Mr. Stradivarius, Mr. Strong Bad, MrGALL, MrOllie, Ms2ger, Muelaner, Mugsywwiii, Mugunth Kumar, Muhdhanis, My name is not dave, MyNameWasTaken, Myas012, Myscrnnm, N Vale, N2e, N5iln, NTox, NYKevin, Naddy, Nagy Dániel, Nagytam, Nahado, Namures, Nantasatria, Nathanloop, Ne0Freedom, NeMeSiS, Nealmcb, NeilN, Neinsun, NetHunter, Newone, Newsoxy, NexuSix, Nexus26, NickGarvey, Nico357, Nicolas Love, Nigelj, Nightscream, Nikhilj1, NiklasBr, Nikpapag, Ninly, Njonji, Nodekeeper, Nogburt, Noloader, Noozgroop, Norm mit, NorthCoastReader, Now wiki, Npx122sy, Nthep, Nuclearmoose, Nuujinn, Nxavar, Nyco, OZODOR, Oatmealr101, Obiwankenobi, Ofennell, Ohaaron, Ohconfucius, Ohnoitsjamie, OlavN, Old Number7, Oldmokmok, Oleg Alexandrov, Oli Filth, Omiqa, Omshivaprakash, Orange Suede Sofa, Originalwana, Ortcutt, OsamaK, OspreyPL, OwenBlacker, Oxwil, P.Shack, P2jones, PILZI, Papatenor, Pascal.Honore, Patrick, Paulmlieberman, Paulscrawl, Paxfeline, Pdfpdf, Pelago, Pelthais, Peter712, Peterkagey, Pgan002, Phalinshah, Phatom87, Philip Trueman, PhosphoricX, Phy1729, Piast93, PieterDeBruijn, Pigr8, Pinball22, Pinecar, PizzaMan, Pjedicke, Pkkasu, Plankhead, PlantRunner, Plarem, Platypus333, Plop, Pluma, Pmod, Pmsyyz, Pmyteh, Poisoncrush2, Pokstad, Pol098, PolarYukon, Pomegranate, Poooooooooo123, Potentials, Pr4733k, PriceChild, Pringo, Prius 2, Privateboz, Procedure, ProfPolySci45, Profvladthethird, Prolog, Prosfilaes, Prototypecreative, Pryanni, Psantora, Pseudomonas, PublicAmpersand, PutzfetzenORG, Pvanderlee, Pwnage97, Quarkgluonsoup, Quartermaster, Quebec99, Queenmomcat, Quiksilver895, Quoth, Qwyrxian, RA0808, RScheiber, Raburton, Rachel263, Ragesoss, Raghualluri, Rahil.kassamali, Rajanbalana, Rajeshsweb, Ral725, Ralfsmouse, RameshaLB, Ramonrabello, Random name, Randomname66, Rapjul, Rapomon, Rapture's Sander Cohen, Ratnok, Ravensfan5252, RaviC, Ravipokemon, Raybob95, Raysonho, Rborghese, Rchandra, RcketScientist, Reaper Eternal, Reatlas, RedHillian, Redekopmark, Reebsauce, Reedy, RegenerateThis, RenamedUser01302013, Renergade1, RenniePet, Renzoy16, Res2216firestar, Resplendent, Return 0 programmer, Rhododendrites, Rich Farmbrough, Richard Arthur Norton (1958- ), Richi, Richiekim, Riffic, Rigelt, Riki, Ringbang, RingtailedFox, Rishav999, Rishify, Rjwilmsi, Rmanke, Robbrown, Robert Moyse, RobertMfromLI, Roberth Edberg, Roberto.larcher, Robferrer, Robzz, Rocboronat, RockJuno, RockMFR, Rockysmile11, Rod92p, Rodeosmurf, Roguegeek, Roif456, Ronnies1312, RotaryAce, Rotlink, Roxx12345, RoyBoy, Royce, Rprpr, Rsrikanth05, Rugops, Runtime, Rush2009, Rwalker, Ryan8374, RyanQuinlan, Ryftstarr, Ryry17354, RzR, Rzęsor, S1lencing, S2333, SCrid2000, SF007, Sachinchavan.in, Sagarwal1981, Saggy84, Saifuddinap, Sailsbystars, Sainath468, Sakthisam, Salamurai, Salazasu, Salvio giuliano, Sam4others, SamJohnston, SamanthaPuckettIndo, Samdman95, Samkass, Samoscool, Samuh, Sandstein, SarekOfVulcan, Sasank, Satellizer, Sayden, Sbmeirow, Sbookface, Scampy11, Sciencewatcher, Scientus, Scl98029, ScotXW, Scott Martin, ScottyWZ, Seanjacksontc, Searchmaven, Secret Agent Julio, Secretlondon, SephirothXIIIX, Seven.cardwell, SeyedKevin, Sfierce, Sfm 7, Shachar, Shaddim, Shadez08, Shadowjams, ShakataGaNai, Shaolinx, SharkD, Shaswat Narendra, Shevett, Shirsakbc, SidP, Sierra1bravo, Sigma2488, Sijil cv, Silvio Marano, Simonrleung, Simple Bob, Sin2x, Sinatosk, Sirlancer, Six words, SixSix, Sjames1, Sjl0523, Skier Dude, Skierpage, Skudo900630, Skype565, Slakr, Slasher-fun, Slatedorg, Sleepy Sentry, Sligocki, Small.is.powerful, Smashville, Smitty, Smurfy, Smyth, Snakeskincowboy, SoWhy, Socialmaven1, Solinym, Solipsys, Solomon Douglas, Soma6, Some jerk on the Internet, Someguy1221, Soulparadox, Southpitt, Sp33dyphil, Spaghetti64, Speculatrix, Spiel, Spiked105, Sreyan, Sriram sh, Staka, StaticGull, Stausifr, Steel, Stefan, Stephenb, Stephenwanjau, Steve03Mills, Steve1428, Stevedel7, Stevejobs24021955, Steveklein, Steven Walling, Stevenbz9, Stevenmitchell, Stevenwagner, StewieK, Strcat, Strz4life, Subbu, Subhanu.bhattacharya, Suckystraw, Suction Man, Sudip1203, Sukael, Sun Creator, Sunnypsyop, Sunray, Superm401, Surv1v4l1st, Suzals3, SvGeloven, Svetovid, Svick, Swampyank, Swatjester, Sygmoral, Sylvainchevalierfu, Syndicate, Syp, T-Nod, T-Rex84, TBrandley, TECfilms, TMO KOTOR, TXI59, Tabletop, Tagrb03f, Tagremover, Tahir mq, Tahitiville, Taras, TarzanJr, TastyCakes, Tavilis, Tazio99, Tbhotch, Tbird20d, Tcncv, Technopat, Tedder, Tedickey, Teeks99, Teginc, Teleprinter

Page 17: Android (Operating System)

Article Sources and Contributors 17

Sleuth, Teles, TempTTC, Tentinator, Tgeairn, The Anome, The Anonymouse, The Letter J, The Ubik, The.rahul.nair, The359, The9Man, TheEditrix2, TheTechFan, TheWishy, Thealexweb,Theanphibian, Theartfullodger, Thecurran91, Themfromspace, Thesamami, Thingg, Thomas.W, ThomasWilson2, Thorwald, Thumperward, Thunder Wolf, Thunderbird8, Thundersoap,Thüringer, Tide rolls, Timeshifter, TimmmmCam, Timneu22, Tobby72, Tobias Bergemann, TobiasPersson, Tobziez, Tomchen1989, Tomlzz1, Tondi5, Tony Sidaway, Tony1, TonyW, TorQueAstur, Torqueing, Traal, Tracer9999, TrbleClef, Trebek Skates, Trefork, Tri400, Trlovejoy, Troed, Trollered32145, Trollskini, Trusilver, Tsriopensourceblueprints, Tuxcantfly, Tweisbach,Txaggiemichael, TyA, Tzw9373, U5K0, UKER, UU, Uffish, Uirauna, Ujimatcha, Ulric1313, Unamed102, Uniwersalista, Unknownwarrior33, Urashimataro, Urfavoritemija, Usafshah, User931,Usmanahmed25, Uvegla, Uzimaster, Vadmium, Vahid83, Vaibhav376, Vald, Van helsing, Varlaam, Vcelloho, Venona, Victorpardosi, Vincenzo.romano, Vineetdhanawat, Vinhtantran,ViperSnake151, Voidvector, Voidxor, VoluntarySlave, Vrenator, Vujke, WakiMiko, Walkop, Walter Görlitz, Walterlmitchell3, Waltonkbbl, Watchcars, Wbison3, Wbm1058, Webclient101,Wednesday Next, Wello95, Werbej, Werdna, Wertydm, Wesleyarchbell, WhatMeWork, Whatiknow, Wickedjacob, Wickorama, Widr, Wifuk, WikiLaurent, WikiRedactor, Wikigod,Wikipedian2009, Wikipelli, Wild mine, William Leadford, Williameis, Windofkeltia, Wintermute115, Wislam, Wizardist, Wknight94, Wlindley, Woohookitty, Woolfy123, WordyMcWordWord, Writermonique, Wschlitz, Wtmitchell, Wwoods, XJaM, Xavierorr, Xcrivener, XdaLive, Xhienne, Xiutwel-0003, Xnamkcor, Xomm, Xrobau, Xsspider, Xx3nvyxx,Y2kcrazyjoker4, YEqxhRDR8pyEqxhRDR8p, YICbaby, Yadavjpr, Yahia.barie, Yamla, Yaohong3914, YasharF, Yellowdesk, Yintan, Yiosie2356, Yizhan, Yngvarr, Yousou, Yowanvista,YuMaNuMa, Yug, Yunshui, Yuriybrisk, Yworo, ZacBowling, Zack0602, Zalunardo8, Zaratoustra, Zbutler7, Zeek Aran, Zeldex, Zero sharp, Zhaofeng Li, ZimZalaBim, Zipcodeman,ZirconiumTwice, Zorak950, Zouzzou, Zundark, Zunmun, ZzRayzZ, ^musaz, Ævar Arnfjörð Bjarmason, Δ, Սահակ, け い ち ゃ, 彭 家 杰, 音 乐 小 白, 계정명뭘로하지, 2857 anonymousedits

Image Sources, Licenses and ContributorsFile:Android robot.svg  Source: http://en.wikipedia.org/w/index.php?title=File:Android_robot.svg  License: Creative Commons Attribution 3.0  Contributors: GoogleFile:Android.svg  Source: http://en.wikipedia.org/w/index.php?title=File:Android.svg  License: Trademarked  Contributors: AndroidFile:Android 4.4 with stock launcher.png  Source: http://en.wikipedia.org/w/index.php?title=File:Android_4.4_with_stock_launcher.png  License: GNU General Public License  Contributors:Screenshot:Himanis Das Operating system: .File:A Press Conference for the Launch of Nexus 7 on September 27, 2012 in Seoul from acrofan 3.JPG  Source:http://en.wikipedia.org/w/index.php?title=File:A_Press_Conference_for_the_Launch_of_Nexus_7_on_September_27,_2012_in_Seoul_from_acrofan_3.JPG  License: unknown  Contributors:ALE!, Mineralsab, RogDel, ViscontinoFile:Android green figure, next to its original packaging.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Android_green_figure,_next_to_its_original_packaging.jpg  License: GNUFree Documentation License  Contributors: DsimicFile:Quad-core Android "mini PC", with a microSD card next to it for a size comparison.jpg  Source:http://en.wikipedia.org/w/index.php?title=File:Quad-core_Android_"mini_PC",_with_a_microSD_card_next_to_it_for_a_size_comparison.jpg  License: GNU Free Documentation License Contributors: DsimicFile:G1, Nexus One, Nexus S, Galaxy Nexus.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:G1,_Nexus_One,_Nexus_S,_Galaxy_Nexus.jpg  License: Creative CommonsAttribution-Sharealike 2.0  Contributors: Duke Q, FlickreviewR, Infrogmation, Materialscientist, OspreyPL, RaviC, SunOfErat, 2 anonymous editsFile:Nexus 5 Front View.png  Source: http://en.wikipedia.org/w/index.php?title=File:Nexus_5_Front_View.png  License: Creative Commons Attribution 2.5  Contributors: Google AndroidFile:Android-System-Architecture.svg  Source: http://en.wikipedia.org/w/index.php?title=File:Android-System-Architecture.svg  License: Creative Commons Attribution-Sharealike 3.0 Contributors: User:SmiehFile:Android App Permissions.png  Source: http://en.wikipedia.org/w/index.php?title=File:Android_App_Permissions.png  License: Apache  Contributors: ScreenshotFile:Android x86 on EeePC 701 4G.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Android_x86_on_EeePC_701_4G.jpg  License: Creative Commons Attribution-Sharealike 3.0 Contributors: User:NzeeminFile:Front view of Nexus 7 (cropped).png  Source: http://en.wikipedia.org/w/index.php?title=File:Front_view_of_Nexus_7_(cropped).png  License: Creative Commons Attribution 2.5 Contributors: Cdwn, DerComputerChecker, Sp33dyphil, TheMostAmazingTechnikFile:Android chart.png  Source: http://en.wikipedia.org/w/index.php?title=File:Android_chart.png  License: Creative Commons Attribution 2.5  Contributors: Android Open Source projectFile:Ouya video game microconsole (9172860385) with transparency.png  Source:http://en.wikipedia.org/w/index.php?title=File:Ouya_video_game_microconsole_(9172860385)_with_transparency.png  License: Creative Commons Attribution-Sharealike 3.0  Contributors:User:Czar

LicenseCreative Commons Attribution-Share Alike 3.0//creativecommons.org/licenses/by-sa/3.0/