Android is a Linux-based operating system primarily designed for mobile devices such as smartphones and tablet computers utilizing ARM processors. A secondary target for the light weight OS is embedded systems such as networking equipment, smart TV systems including set top boxes and built in systems and various devices as varied as house hold appliances and wrist watches. Most embedded applications are for ARM based devices but notably Google's Google TV devices use Intel chips with the x86 version of Android. The x86 processor architecture is also utilized, to a lesser extent, in traditional personal computer applications most notably with netbooks and, rarely, laptops and desktops. It is developed by the Open Handset Alliance, led by Google.
Google financially backed the initial developer of the software, Android Inc., and later purchased it in 2005.The unveiling of the Android distribution in 2007 was announced with the founding of the Open Handset Alliance, a consortium of 86 hardware, software, and telecommunication companies devoted to advancing open standards for mobile devices.Google releases the Android code as open-source, under the Apache License.The Android Open Source Project (AOSP) is tasked with the maintenance and further development of Android.
Android has a large community of developers writing applications ("apps") that extend the functionality of the devices. Developers write primarily in a customized version of Java.Apps can be downloaded from third-party sites or through online stores such as Google Play (formerly Android Market), the app store run by Google. In June 2012, there were more than 600,000 apps available for Android, and the estimated number of applications downloaded from Google Play was 20 billion.
Android became 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.
Android, Inc. was founded in Palo Alto, California, United States in October 2003 by Andy Rubin (co-founder of Danger), Rich Miner (co-founder of Wildfire Communications, Inc.),Nick Sears (once VP at T-Mobile),and Chris White (headed design and interface development at WebTV 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. Steve Perlman, a close 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, 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 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 makers and carriers 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 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. Some speculated that as Google was defining technical specifications, it was showing prototypes to cell phone manufacturers and network operators.n September 2007, InformationWeek covered an Evalueserve study reporting that Google had filed several patent applications in the area of mobile telephony.
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.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. On December 9, 2008, 14 new members joined, including ARM Holdings, Atheros Communications, Asustek Computer Inc, Garmin Ltd, Huawei Technologies, PacketVideo, Softbank, Sony Ericsson, Toshiba Corp, and Vodafone Group Plc.
The Android Open Source Project (AOSP) is led by Google, and is tasked with the maintenance and development of Android.According to the project "The goal 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 SDK and NDK", 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.
Android consists of a kernel based on the Linux kernel 2.6, with middleware, libraries and APIs written in C and application software running on an application framework which includes Java-compatible libraries based on Apache Harmony. Android uses the Dalvik virtual machine with just-in-time compilation to run Dalvik dex-code (Dalvik Executable), which is usually translated from Java bytecode.The main hardware platform for Android is the ARM architecture. There is support for x86 from the Android x86 project,and Google TV uses a special x86 version of Android.
Android's kernel is based on the Linux kernel and has further architecture changes by Google outside the typical Linux kernel development cycle.Android does not have a native X Window System by default nor does it support the full set of standard GNU 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,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 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, Linus Torvalds 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, Greg Kroah-Hartman announced the start of the Android Mainlining Project, which aims to put some Android drivers, patches and features back into the Linux kernel, starting in Linux 3.3. further integration being expected for Linux Kernel 3.4.
