Android : Introduction

•      Linux-based operating system

•     Designed primarily for touchscreen mobile devices such as smartphones and tablet computers.

•     Currently developed by Google.

•     Initially developed by Android Inc, whom Google financially backed and later purchased in 2005.

•      The Android Software Development Kit (Android SDK) provides all necessary tools to develop Android applications. This includes a compiler, debugger and a device emulator, as well as its own virtual machine to run Android programs

Android is open source and Google releases the code under the Apache License

Android applications run in a sandbox, an isolated area of the system that does not have access to the rest of the system's resources, unless access permissions are explicitly granted by the user when the application is installed. Before installing an application, the Play Store displays all required permissions

The source code for Android is available under free and open source software licenses. Google publishes most of the code (including network and telephony stacks)^[104] under the Apache License version 2.0  

The version history of the Android mobile operating system began with the release of the Android beta in November 2007. The first commercial version, Android 1.0, was released in September 2008

Below is List of Android Version and API Level

 

Version	Code name	Release date	API level
4.2	Jelly Bean	November 13, 2012	17
4.1.x	Jelly Bean	July 9, 2012	16
4.0.x	Ice Cream Sandwich	December 16, 2011	15
3.2	Honeycomb	July 15, 2011	13
3.1	Honeycomb	May 10, 2011	12
2.3.3–2.3.7	Gingerbread	February 9, 2011	10
2.3–2.3.2	Gingerbread	December 6, 2010	9
2.2	Froyo	May 20, 2010	8
2.0–2.1	Eclair	October 26, 2009	7
1.6	Donut	September 15, 2009	4