Android is an operating system for mobile devices such as cellular Android Phones, tablet computers and netbooks. Android is developed by Google and is based upon the Linux kernel and GNU software. It was initially developed by Android Inc. (a firm later purchased by Google) and lately broadened to the Open Handset Alliance. According to NPD Group, unit sales for Android OS smartphones ranked first among all smartphone OS handsets sold in the U.S. in the second quarter of 2010, at 33%. BlackBerry OS is second at 28%, and iOS is ranked third with 22%.
Android has a large community of developers writing application programs (“apps”) that extend the functionality ### of the devices. There are currently over 70,000 apps available for Android with some estimates saying 100,000 have been submitted, which makes it the second most popular mobile development environment. Developers write managed code in the Java language, controlling the device via Google-developed Java libraries.
The unveiling of the Android distribution on 5 November 2007 was announced with the founding of the Open Handset Alliance, a consortium of 71 hardware, software, and telecom companies devoted to advancing open standards for mobile devices. Google released most of the Android code under the Apache License, a free software and open source license.
The Android operating system 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 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 consists of 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++.