Android (operating system)
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Home screen displayed by Samsung Nexus S with Google running Android 2.3 "Gingerbread" | |
| Company / developer | Google Inc., Open Handset Alliance |
| Programmed in | C (core),[1] Java (UI) |
| Working state | Current |
| Source model | Free and open source software (3.0 is currently still closed source) [2] |
| Initial release | 21 October 2008 |
| Latest stable release | Tablets: 3.1 (Honeycomb)[3] Phones: 2.3.4 (Gingerbread) / 24 February 2011[3] |
| Supported platforms | ARM, MIPS,[4] x86[5][citation needed] |
| Kernel type | Linux kernel |
| Default user interface | Graphical |
| License | Apache 2.0, Linux kernel patches are under GPL v2[6] |
| Official website | android.com |
Android is a software stack for mobile devices that includes an operating system, middleware and key applications.[7][8] Google Inc. purchased the initial developer of the software, Android Inc., in 2005.[9] Android's mobile operating system is based on the Linux kernel. Google and other members of the Open Handset Alliance collaborated on Android's development and release.[10][11] The Android Open Source Project (AOSP) is tasked with the maintenance and further development of Android.[12] The Android operating system is the world's best-selling Smartphone platform.[13][14]
Android has a large community of developers writing applications ("apps") that extend the functionality of the devices. There are currently over 200,000 apps available for Android.[15][16] Android Market is the online app store run by Google, though apps can also be downloaded from third-party sites. Developers write primarily in the Java language, controlling the device via Google-developed Java libraries.[17]
The unveiling of the Android distribution on 5 November 2007 was announced with the founding of the Open Handset Alliance, a consortium of 80 hardware, software, and telecom companies devoted to advancing open standards for mobile devices.[18][19] Google released most of the Android code under the Apache License, a free software and open source license.[20]
The Android open-source software stack consists of Java applications running on a Java-based, object-oriented application framework on top of Java core libraries running on a Dalvik virtual machine featuring JIT compilation. Libraries written in C include the surface manager, OpenCore[21] media framework, SQLite relational database management system, OpenGL ES 2.0 3D graphics API, WebKit layout engine, SGL graphics engine, SSL, and Bionic libc. The Android operating system, including the Linux kernel, consists of roughly 12 million lines of code including 3 million lines of XML, 2.8 million lines of C, 2.1 million lines of Java, and 1.75 million lines of C++.[22] History
Android Inc. founded in 2003
Android, Inc. was founded in Palo Alto, California, United States in October, 2003 by Andy Rubin (co-founder of Danger),[23] Rich Miner (co-founder of Wildfire Communications, Inc.),[24] Nick Sears (once VP at T-Mobile),[25] and Chris White (headed design and interface development at WebTV) [26] to develop, in Rubin's words "...smarter mobile devices that are more aware of its owner's location and preferences."[27] Despite the obvious past accomplishments of the founders and early employees, Android Inc. operated secretively, admitting only that it was working on software for mobile phones.[27]
[edit] Android Inc. acquired by Google
Google acquired Android Inc. in August, 2005, making Android Inc. a wholly owned subsidiary of Google Inc. Key employees of Android Inc., including Andy Rubin, Rich Miner and Chris White, stayed at the company after the acquisition.[24]
Not much was known about Android Inc. at the time of the acquisition, but many assumed that Google was planning to enter the mobile phone market with this move.
[edit] Development accelerates
At Google, the team led by Rubin developed a mobile device platform powered by the Linux kernel. Google marketed the platform to handset makers and carriers on the premise 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.[28][29][30]
Speculation about Google's intention to enter the mobile communications market continued to build through December 2006.[31] Reports from the BBC and The Wall Street Journal noted that Google wanted its search and applications on mobile phones and it was working hard to deliver that. Print and online media outlets soon reported rumors that Google was developing a Google-branded handset.[32] Some speculated that as Google was defining technical specifications, it was showing prototypes to cell phone manufacturers and network operators.
In September 2007, InformationWeek covered an Evalueserve study reporting that Google had filed several patent applications in the area of mobile telephony.[33][34]
[edit] Open Handset Alliance
Main article: Open Handset Alliance
"Today's announcement is more ambitious than any single 'Google Phone' that the press has been speculating about over the past few weeks. Our vision is that the powerful platform we're unveiling will power thousands of different phone models."
Eric Schmidt, former Google Chairman/CEO[10]
On November 5, 2007 the Open Handset Alliance, a consortium of several companies which include Broadcom Corporation, Google, HTC, Intel, LG, Marvell Technology Group, Motorola, Nvidia, Qualcomm, Samsung Electronics, Sprint Nextel, T-Mobile and Texas Instruments unveiled itself. The goal of the Open Handset Alliance is to develop open standards for mobile devices.[10] On the same day, the Open Handset Alliance also unveiled their first product, Android, a mobile device platform built on the Linux kernel version 2.6.[10]
On December 9, 2008, 14 new members joined, including ARM Holdings, Atheros Communications, Asustek Computer Inc, Garmin Ltd, PacketVideo, Softbank, Sony Ericsson, Toshiba Corp, and Vodafone Group Plc.[35][36]
[edit] Licensing
With the exception of brief update periods, Android has been available under a free software/open source license since October, 21 2008. Google published the entire source code (including network and telephony stacks)[37] under an Apache License.[38] Google also keeps the reviewed issues list publicly open for anyone to see and comment.[39]
Even though the software is open-source, device manufacturers can not use Google's Android trademark unless Google certifies that the device complies with their Compatibility Definition Document (CDD). Devices must also meet this definition to be eligible to license Google's closed-source applications, including the Android Market.[40]
In September 2010, Skyhook Wireless filed a lawsuit against Google in which they alleged that Google had used the compatibility document to block Skyhook's mobile positioning service (XPS) from Motorola's Android mobile devices.[41] In December 2010 a judge denied Skyhook's motion for preliminary injunction, saying that Google had not closed off the possibility of accepting a revised version of Skyhook's XPS service, and that Motorola had terminated their contract with Skyhook because Skyhook wanted to disable Google's location data collection functions on Motorola's devices, which would have violated Motorola's obligations to Google and its carriers.[42]
[edit] Version history
Main article: Android version history
Android has seen a number of updates since its original release. These updates to the base operating system typically fix bugs and add new features. Generally, each new version of the Android operating system is developed under a code name based on a dessert item. Past updates included Cupcake and Donut. The code names are in alphabetical order (Cupcake, Donut, Eclair, Froyo, Gingerbread, Honeycomb, and the upcoming Ice Cream Sandwich).
The most recently released versions of Android are:
- 2.0/2.1 (Eclair), which revamped the user interface and introduced HTML5 and Exchange ActiveSync 2.5 support[43]
- 2.2 (Froyo), which introduced speed improvements with JIT optimization and the Chrome V8 JavaScript engine, and added Wi-Fi hotspot tethering and Adobe Flash support[44]
- 2.3 (Gingerbread), which refined the user interface, improved the soft keyboard and copy/paste features, and added support for Near Field Communication[45]
- 3.0/3.1 (Honeycomb), a tablet-oriented[46][47][48] release which supports larger screen devices and introduces many new user interface features, and supports multicore processors and hardware acceleration for graphics.[49] The Honeycomb SDK has been released and the first device featuring this version, the Motorola Xoom tablet, went on sale in February 2011.[50] Google has chosen to withhold the Honeycomb source code, which called into question the "open-ness" of this Android release.[51] Google's Andy Rubin stated that the latest Android source code would be released "when it is ready". The reason for the delay, according to Rubin in an official Android blog post, was because Honeycomb was rushed for production of the Motorola Xoom.[52] Google later confirmed that the Honeycomb source code would not be released until after it was merged with the Gingerbread release in Ice Cream Sandwich.[53] The 3.1 update has been announced at the 2011 Google I/O on 10 May 2011.[54]
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