ANDROID System Architecture

A central design point of the Android security architecture is that no application, by default, has permission to perform any operations that would adversely impact other applications, the operating system, or the user. This includes reading or writing the user's private data such as   contacts or e-mails, reading or writing another application's files, performing network access, keeping the device awake, etc. An application's process is a secure sandbox. It can't disrupt other applications, except by explicitly declaring the permissions.

It needs for additional capabilities not provided by the 

Basic sand box. These permissions it requests can be handled by the operating in various ways, typically by automatically allowing or disallowing based on certificates or by prompting the user. The permissions required by an application are declared statically in that application, so they can be known up-front at install time and will not change after that

·        Features:-

Connectivity:- Android supports connectivity technologies including GSM/EDGE, IDEN, CDMA, EV-DO, UMTS, Bluetooth, Wi-Fi, LTE, NFC and Wi MAX.

Multiple language support: Android supports multiple languages.

. Web browser: - The web browser available in Android is based on the open-source Web Kit layout engine, coupled with Chrome's V8 JavaScript engine. The browser scores 100/100 on the Acid3 test on Android 4.0.

Java support: - While most Android applications are written in Java, there is no Java Virtual Machine in the platform and Java byte code is not executed. Java classes are compiled into Davis executables and run on Davis, a specialized virtual machine designed specifically for Android and optimized for battery-powered mobile devices with limited memory and CPU. J2ME support can be provided via third-party applications.

 Media support:- Android supports the following audio/video/still media formats: WebMD, H.263, H.264 (in 3GP or MP4 container), MPEG-4 SP, AMR, AMR-WB (in 3GP container), AAC, HE-AAC (in MP4 or 3GP container), MP3, MIDI, Gog Verb’s, FLAC, WAV, JPEG, PNG, GIF, BMP,Web

 Additional hardware support:- Android can use video/still cameras, touch screens, GPS, accelerometers, gyroscopes, barometers, magnetometers, dedicated gaming controls, proximity and pressure sensors, thermometers, accelerated 2D bit blitz (with hardware orientation, scaling, pixel format conversion) and accelerated 3D graphics

 Multi-touch:- Android has native support for multi-touch which was initially made available in handsets such as the HTC Hero. The feature was originally disabled at the kernel level (possibly to avoid infringing Apple's patents on touch-screen technology at the time). Google has since released an update for the Nexus One and the Motorola Droid which enables multi-touch natively.