ANDROID MOBILE OPERATING SYSTEM

Android mobile operating system is based on the Linux kernel and it is a software stack for mobile devices. This operating system is one of the world's best-selling Smartphone platform.

Android involves many developers writing applications that helps in extended the functionality of the devices. There are currently over 1,50,000 and more applications available for Android. Android Market is the online application store run by Google, though applications can also be downloaded from third-party sites. Developers write in the Java language. 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. Most of the Android code is released by Google under the Apache License. The Android open-source software stack consists of Java applications running on a Java-based, object-oriented applicationlication framework on top of Java core libraries . Libraries written in C include SQLite relational database management system, WebKit layout engine, SGL graphics engine, SSL. The Android operating system, including the Linux kernel, consists of roughly 12million lines of code including 3million lines of XML, 2.8million lines of C, 2.1million lines of Java, and 1.75million lines of C++. The main supported platform for Android is the ARM (Advanced Risc Machines) architecture.ARM is one of the most licensed and thus widespread processor cores in the world. It is used especially in portable devices due to low power consumption and reasonable performance.



 Now a days cell phones, note books and tablets, including the Dell Streak, Samsung Galaxy Tab, TV and other devices can use the functionality of Android . HTC Dream was the first phone to run android, released on 22 October 2008. Android applications are written in the Java programming language. By the help of SDK tools Android's code is compiled with data and resource file. An archive file has .apk extension. All the code in a single .apk file is considered to be one application. By the help of this file, Android devices use to install the application. Android provides the ability to build extremely rich and innovative applications due to open source platform. These are the services which are provided by it like device hardware, access location information, run background services, set alarms, add notifications to the status bar, and much more.Developers have full access to the same framework APIs used by the core applications. The application architecture is designed to simplify the reuse of components; any application can publish its capabilities and any other application may then make use of those capabilities .This same mechanism allows components to be replaced by the user.