Android is an operating system for mobile devices such as smartphones and tablet computers. It is developed by the Open Handset Alliance led by Google. The stated goal of this open source project is to create a successful real-world product that improves the mobile experience for end users.
Android's kernel is based on the Linux kernel and has further architecture changes by Google outside the typical Linux kernel development cycle. The Android OS does not have a native X Window System 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.Android Versions for different devices:
Android 2.3 is codenamed Gingerbread refined the user interface, improved the soft keyboard and copy/paste features, improved gaming performance, added SIP support
(VoIP calls), and added support for Near Field Communication.
Android 3.0 codenamed Honeycomb
was a tablet-oriented release which supports larger screen devices and introduces many new user interface features, support for multi-core processors, hardware acceleration for graphics and full system encryption. The first device featuring this version, the Motorola Xoom tablet, went on sale in February 2011.
Android 3.1 Honeycomb
released in May 2011, added support for extra input devices, USB host mode for transferring information directly from cameras and other devices, and the Google Movies and Books apps.Android 3.2 Honeycomb
, released in July 2011, added optimization for a broader range of screen sizes, new "zoom-to-fill" screen compatibility mode, loading media files directly from SD card, and an extended screen support API. Huawei MediaPad is the first 7 inch tablet to use this version.
Android 4.0 codenamed Ice Cream Sandwich
, announced on October 19, 2011, brought Honeycomb features to smartphones and added new features including facial recognition unlock, network data usage monitoring and control, unified social networking contacts, photography enhancements, offline email searching, app folders, and information sharing using NFC. Android 4.0.3 Ice Cream Sandwich is the latest Android version that is available to phones.Android Market :
The Android Market is the online software store developed by Google for Android devices. An application program ("app") called "Market" is preinstalled on most Android devices and allows users to browse and download apps published by third-party developers, hosted on Android Market.
As of October 2011 there were more than 300,000 apps available for Android, and the estimated number of applications downloaded from the Android Market as of December 2011 exceeded 10 billion. The operating system itself is installed on 130 million total devices.
Only devices that comply with Google's compatibility requirements are allowed to preinstall Google's closed-source Android Market app and access the Market. The Market filters the list of applications presented by the Market app to those that are compatible with the user's device, and developers may restrict their applications to particular carriers or countries for business reasons.
Alternatively, users can install apps directly onto the device if they have the application's APK file or from third party app stores such as the Amazon Appstore.