Android is a -based such as and . It is developed by the , led by , and other companies. Google purchased the initial developer of the software, Android Inc., in 2005. The unveiling of the Android distribution in 2007 was announced with the founding of the Open Handset Alliance, a consortium of 86 , software, and companies devoted to advancing for mobile devices. Google releases the Android code as , under the . The (AOSP) is tasked with the maintenance and further development of Android. Android has a large community of developers writing applications (" ") that extend the functionality of the devices. Developers write primarily in a customized version of . Apps can be downloaded from third-party sites or through online stores such as (formerly Android Market), the app store run by Google. In October 2011, there were more than 500,000 apps available for Android, and the estimated number of applications downloaded from the Android Market as of December 2011 exceeded 10 billion. Androidbecame the world’s leading smartphone platform at the end of 2010. For the first quarter of 2012, Android had a 59% smartphone market share worldwide. At the half of 2012, there were 400 million devices activated and 1 million activations per day. Analysts point to the advantage to Android of being a multi-channel, multi-carrier OS. History Foundation Android, Inc. was founded in , United States in October 2003 by (co-founder of ), (co-founder of Wildfire Communications, Inc.), Nick Sears (once VP at ), and Chris White (headed design and interface development at ) to develop, in Rubin's words "...smarter mobile devices that are more aware of its owner's location and preferences". Despite the obvious past accomplishments of the founders and early employees, Android Inc. operated secretly, revealing only that it was working on software for mobile phones. That same year, Rubin ran out of money. , a close friend of Rubin, brought him $10,000 in cash in an envelope and refused a stake inthe company. Acquisition by Google acquired Android Inc. on August 17, 2005, making Android Inc. a wholly owned subsidiary of Google. Key employees of Android Inc., including Andy Rubin, Rich Miner and Chris White, stayed at the company after the acquisition. Not much was known about Android Inc. at the time of the acquisition, but many assumed that Google was planning to enter the market with this move. Post-acquisition development At , the team led by Rubin developed a mobile device platform powered by the . Google marketed the platform to handset makers and on the promise of providing a flexible, upgradable system. Google had lined up a series of hardware component and software partners and signaled to carriers that it was open to various degrees of cooperation on their part. Speculation about Google's intention to enter the mobile communications market continued to build through December 2006. Reports from the and noted that Google wanted its search and applications on mobilephones and it was working hard to deliver that. Print and online media outlets soon reported rumors that Google was developing a Google-branded . Some speculated that as Google was defining technical specifications, it was showing prototypes to cell phone manufacturers and network operators. In September 2007, covered an study reporting that Google had filed several applications in the area of mobile telephony. Open Handset Alliance Main article: On November 5, 2007, the Open Handset Alliance, a of several companies which include , , , , , , , , , , , and unveiled itself. The goal of the Open Handset Alliance is to develop for mobile devices. On the same day, the Open Handset Alliance also unveiled their first product, Android, a mobile device built on the version 2.6. On December 9, 2008, 14 new members joined, including , , , , , , , , , and . Android Open Source Project The is led by Google, and is tasked with the maintenance and development of Android. According to the project "Thegoal of the Android Open Source Project is to create a successful real-world product that improves the mobile experience for end users." AOSP also maintains the Android Compatibility Program, defining an "Android compatible" device "as one that can run any application written by third-party developers using the Android and ", to prevent incompatible Android implementations. The compatibility program is also optional and free of charge, with the Compatibility Test Suite also free and open-source. Version history Main article: From left to right: , , , Android has been updated frequently since the original release of "Astro", with each fixing and adding new features. Each version is named in alphabetical order, with 1.5 "Cupcake" being the first named after a and every update since following this naming convention. Design Architecture diagram Android consists of a based on the , with , and written in and running on an which includes Java-compatible libraries based on . Android uses thewith to run Dalvik dex-code (Dalvik Executable), which is usually translated from bytecode. The main hardware platform for Android is the . There is support for from the project, and Google TV uses a special x86 version of Android. Linux Android's kernel is based on the and has further architecture changes by Google outside the typical Linux kernel development cycle. Android does not have a native nor does it support the full set of standard libraries, and this makes it difficult to port existing Linux applications or libraries to Android. 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 kernel maintainers felt that Google did not show any intent to maintain their own code. Even though Google announced in April 2010 that they would hire two employees to work with the Linux kernel community, , the current Linux kernel maintainer for the -stable branch, saidin December 2010 that he was concerned that Google was no longer trying to get their code changes included in mainstream Linux. Some Google Android developers hinted that "the Android team was getting fed up with the process", because they were a small team and had more urgent work to do on Android. However, in September 2010, Linux kernel developer Rafael J. Wysocki added a patch that improved the mainline Linux wakeup events framework. He said that Android device drivers that use wakelocks can now be easily merged into mainline Linux, but that Android's opportunistic suspend features should not be included in the mainline kernel. In August 2011, said that "eventually Android and Linux would come back to a common kernel, but it will probably not be for four to five years". In December 2011, announced the start of the Android Mainlining Project, which aims to put some Android , patches and features back into the Linux kernel, starting in Linux 3.3. further integration being expectedfor Linux Kernel 3.4. Features The Android Emulator default home screen (v1.5, also known as "Cupcake") Current features and specifications: Handset layouts The platform is adaptable to larger, , library, library based on 2.0 specifications, and traditional smartphone layouts. Storage , a lightweight , is used for storage purposes. Connectivity Android supports connectivity technologies including / , , , , , , , , and . Messaging and are available forms of messaging, including threaded and now (C2DM) is also a part of Android Push Messaging service. Multiple language support Android supports multiple languages. Web browser The web browser available in Android is based on the open-source layout engine, coupled with 's . The browser scores 100/100 on the test on Android 4.0. Java support While most Android applications are written in , there is no in the platform and Java byte code is not executed. Java classes are compiled into Dalvik executables and run on , a specialized virtualmachine designed specifically for Android and optimized for battery-powered mobile devices with limited memory and CPU. support can be provided via third-party applications. Media support Android supports the following audio/video/still media formats: , , (in or ), , , (in 3GP container), , (in MP4 or 3GP container), , , , , , , , , , . Streaming media support RTP/RTSP streaming ( , ), HTML progressive download ( ). Adobe Flash Streaming (RTMP) and HTTP Dynamic Streaming are supported by the . Apple HTTP Live Streaming is supported by , and by the operating system in Android 3.0 (Honeycomb). Additional hardware support Android can use video/still cameras, , , , , , , dedicated gaming controls, and , , accelerated 2D (with hardware orientation, scaling, pixel format conversion) and accelerated 3D graphics. Multi-touch Android has native support for which was initially made available in handsets such as the . The feature was originally disabled at the kernel level (possibly to avoidinfringing Apple's patents on touch-screen technology at the time). Google has since released an update for the and the which enables multi-touch natively. Bluetooth Supports , , sending files ( ), accessing the phone book ( ), voice dialing and sending contacts between phones. Keyboard, mouse and joystick ( ) support is available in Android 3.1+, and in earlier versions through manufacturer customizations and third-party applications. Video calling Android does not support native video calling, but some handsets have a customized version of the operating system that supports it, either via the network (like the ) or over IP. Video calling through Google Talk is available in Android 2.3.4 and later. Gingerbread allows to place Internet calls with a SIP account. This allows for enhanced VoIP dialing to other SIP accounts and even phone numbers. Skype 2.1 offers video calling in Android 2.3, including front camera support. Multitasking Multitasking of applications, with unique handlingof memory allocation, is available. Voice based features Google search through voice has been available since initial release. Voice actions for calling, texting, navigation, etc. are supported on Android 2.2 onwards. Tethering Android supports , which allows a phone to be used as a wireless/wired . Before Android 2.2 this was supported by third-party applications or manufacturer customizations. Screen capture Android supports capturing a by pressing the power and volume-down buttons at the same time. Prior to Android 4.0, the only methods of capturing a screenshot were through manufacturer and third-party customizations or otherwise by using a PC connection (DDMS developer's tool). These alternative methods are still available with the latest Android. External storage Most Android devices include microSD slot and can read microSD cards formatted with , or file system. To allow use of high-capacity storage media such as and , many Android tablets also include 'A' receptacle. Storageformatted with is handled by VFAT driver, while 3rd party solutions are required to handle other popular file systems such as , and . Uses See also: home screen While Android is designed primarily for smartphones and tablets, the open and customizable nature of the operating system allows it to be used on other electronics, including and , , , and ( ). Further, the OS has seen niche applications on , , car CD and DVD players, smart glasses ( ), refrigerators, vehicle satnav systems, home automation systems, games consoles, mirrors, cameras, , and treadmills. The first commercially available phone to run Android was the , released on October 22, 2008. In early 2010 Google collaborated with to launch its flagship Android device, the . This was followed later in 2010 with the -made and in 2011 with the . and Android 2.3.3 'Gingerbread' may be set up to dual boot on a with the help of and iDroid. In December 2011 it was announced has officially approved Android for use by its personnel.Applications See also: and Applications are usually developed in the language using the , but other development tools are available, including a for applications or extensions in C or C++, , a visual environment for novice programmers and various . Applications can be acquired by end-users either through a store such as or the , or by downloading and installing the application's file from a third-party site. Google Play The on a . Main article: is an online software store developed by Google for Android devices. An application program ("app") called "Play Store" is preinstalled on most Android devices and allows users to browse and download apps published by third-party developers, hosted on Google Play. As of October 2011, there were more than 500,000 apps available for Android, and the estimated number of applications downloaded from the Play Store as of June 2012 exceeded 20 billion. The operating system itself is installed on 130 million total devices. Only devices that complywith Google's compatibility requirements are allowed to preinstall and access the Play Store. The app filters the list of available applications to those that are compatible with the user's device, and developers may restrict their applications to particular carriers or countries for business reasons. has participated in the Play Store by offering many free applications themselves, including , , Gesture Search, , Google Shopper, Listen and My Tracks. In August 2010, Google launched "Voice Actions for Android", which allows users to search, write messages, and initiate calls by voice. Security See also: An example of app permissions in the Play Store. Android applications run in a , an isolated area of the operating system that does not have access to the rest of the system's resources, unless access permissions are granted by the user when the application is installed. Before installing an application, the displays all required permissions. A game may need to enable vibration, forexample, but should not need to read messages or access the phonebook. After reviewing these permissions, the user can decide whether to install the application. The sandboxing and permissions system weakens the impact of vulnerabilities and bugs in applications, but developer confusion and limited documentation has resulted in applications routinely requesting unnecessary permissions, reducing its effectiveness. The complexity of inter-application communication implies Android has a large attack surface. Several security firms have released antivirus software for Android devices, in particular, , , , , and . This software is ineffective as sandboxing also applies to such applications, limiting their ability to scan the deeper system for threats. Privacy Android smartphones have the ability to report the location of access points, encountered as phone users move around, to build databases containing the physical locations of hundreds of millions of such access points. These databasesform electronic maps to locate smartphones, allowing them to run apps like , , , 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 March 2012 it was revealed that Android Apps can copy photos without explicit user permission, Google responded they "originally designed the Android photos file system similar to those of other computing platforms like Windows and Mac OS. [...] we're taking another look at this and considering adding a permission for apps to access images. We've always had policies in place to remove any apps [on Google Play] that improperly access your data." Marketing The Android logotype was designed along with the by , the robot icon was designed by Irina Blok. Android Green is the color of the Android Robot that represents the Android operating system. The print color is 376C and the valuein hexadecimal is #A4C639, as specified by the Android Brand Guidelines. The custom typeface of Android is called Norad (cf. ). It is only used in the text logo. Market share period worldwide smartphones market U.S. smartphone market global devices activations per day U.S devices source Q2 2009 2.8% 12,100 Canalys Q3 2009 4% 8% 18,000 Q4 2009 8.7% 51,100 Canalys 2009 9.7% North America, Canalys February 2010 4,09 million 9% of 45.4 million U.S. smartphones, Q1 2010 28 % NPD Group Android outsold Apple's iPhone in the U.S. May 2010 100,000 June 2010 33% 160,000 Q3 2010 25.3% 43.6% 223,000 September 2010 12.6 million 21.4% of the 58.7 million U.S. smartphones Q4 2010 32.9% 362,000 Canalys. February 2011 23.8 million comscore (63% of the number of iOS devices) Q1 2011 35% 393,000 Canalys, 4 May 2011. 10 May 2011 100 million 400,000 Google I/O 28 June 2011 500,000 a 4.4% weekly growth, Andy Rubin Q2 2011 48% 52% 568,000 Canalys, 1 August 2011 July 14, 2011 550,000 4.4% growth per week.Google Q3 2011 52.5% 658,000 October 13, 2011 190 million Google November 16, 2011 200 million during the announcement "These Go to Eleven" 3.8 million Android Honeycomb Tablets have been sold. December 20, 2011 250 million 700,000 , Google 27 February 2012 300 million 850,000 250% yearly growth rate. Andy Rubin, Google Q1 2012 59% 331 million 934,000 85 millions in 91 days, Signals and Systems Telecom 27 June 2012 400 million 1 million Google Usage share Usage share of the different versions as of June 1, 2012 Usage share of the different versions as of June 1, 2012. Most Android devices to date run the older OS version 2.3.x Gingerbread that was released on December 6, 2010, even though the newest OS version, 4.0.x Ice Cream Sandwich has been released since October 2011. Version Release date level Distribution 4.1.x Jelly Bean June 28, 2012 16 Not Yet Known 4.0.x Ice Cream Sandwich October 19, 2011 14-15 7.1% 3.x.x Honeycomb February 22, 2011 11-13 2.7% 2.3.x Gingerbread December 6,2010 9-10 65% 2.2 Froyo May 20, 2010 8 19.1% 2.0, 2.1 Eclair October 26, 2009 7 5.2% 1.6 Donut September 15, 2009 4 0.6% 1.5 Cupcake April 30, 2009 3 0.3% Intellectual property Licensing The for Android is available under licenses. publishes most of the code (including network and telephony ) under the version 2.0, and the rest, Linux kernel changes, under the version 2. The develops the changes to the Linux kernel, in public, with source code publicly available at all times. The rest of Android is developed in private, with source code released publicly when a new version is released. Typically Google collaborates with a hardware manufacturer to produce a flagship device (part of the series) featuring the new version of Android, then makes the source code available after that device has been released. In early 2011, Google chose to temporarily withhold the Android source code to the tablet-only Honeycomb release, the reason, according to in an official Android blog post, was becauseHoneycomb was rushed for production of the , and they did not want third parties creating a "really bad user experience" by attempting to put onto smartphones a version of Android intended for tablets. The source code was once again made available in November 2011 with the release of Android 4.0. Copyrights and patents Further information: Both Android and Android phone manufacturers have been the target of numerous patent lawsuits. On August 12, 2010, sued Google over claimed infringement of copyrights and patents related to the programming language. Oracle originally sought damages up to $6.1 billion, but this valuation was rejected by a federal 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 , a implementation of the Java class libraries, and anindependently developed virtual machine called . In May 2012 the jury in this case found that Google did not infringe on Oracle's patents, and the trial judge ruled that the structure of the Java APIs used by Google was not copyrightable. has also sued several manufacturers of Android devices for patent infringement, and collects patent licensing fees from others. In October 2011 Microsoft said they had signed license agreements with ten Android device manufacturers, accounting for 55% of worldwide revenue for Android devices. These include and . Google has publicly expressed its dislike for the current patent landscape in the United States, accusing , Oracle and Microsoft of trying to take down Android through patent litigation, rather than innovating and competing with better products and services. In August 2011, Google started the process of purchasing for 12.5 billion, which was viewed in part as a defensive measure to protect Android, since Motorola Mobility holds more than17,000 patents. In December 2011 Google acquired in the region of a thousand patents from . Posted in: