30-04-2011, 04:51 PM
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ANDROID MOBILE OPErATING SYSTEM
INTRODUCTION
Android is a mobile operating system initially developed by Android Inc.
Android was bought by GOOGLE in 2005.
Android is based upon a modified version of the linux kernel 2.6
Android OS is a software stack consisting of java application running on a Java application framework on top of java core library running on Dalvik virtual machine.
HISTORY
ANDROID was founded by ANDY RUBIN , RICH MINER, NICK SEARS & CHRIS WHITE who used to work at GOOGLE.
Android was bought by GOOGLE in 2005.
On the 5th of November 2007 the Open Handset Alliance, a consortium of several companies was unveiled with the goal to develop open standards for mobile devices
ARCHITECTURE
ARCHITECTURE DESCRIPTION
APPLICATION FRAMEWORK
phone software like phone diary, call setup, resource manager, installers are part of application framework.
A notification manager that enables all applications to display custom alerts in the status bar.
An activity manager that manages the lifecycle of applications and provides a common navigation backstage.
LIBRARIES
System C library - a BSD-derived implementation of the standard C system library (libc), tuned for embedded Linux-based devices.
Media Libraries -supports playback and recording of many popular audio and video formats, as well as static image files, including MPEG4, H.264, MP3, AAC, AMR, JPG, and PNG.
Surface Manager - manages access to the display subsystem and seamlessly composites 2D and 3D graphic layers from multiple applications.
LibWebCore - a modern web browser engine which powers both the Android browser and an embeddable web view.
SGL - the underlying 2D graphics engine.
3D libraries - an implementation based on OpenGL ES 1.0 APIs the libraries use either hardware 3D acceleration (where available) or the highly optimized 3D software rasterizer
FreeType - bitmap and vector font rendering
SQLite - a powerful and lightweight relational database engine available to all applications.
ANDROID RUNTIME
Every Android application runs in its own process, with its own instance of the Dalvik virtual machine.
The Dalvik VM executes files in the Dalvik Executable (.dex) format.
Dalvik has been written so that a device can run multiple VMs efficiently.
LINUX KERNEL
Android relies on Linux version 2.6 for core system services such as security, memory management, process management, network stack, and driver model.
The kernel also acts as an abstraction layer between the hardware and the rest of the software stack.
FEATURES
Application framework : enabling reuse & replacement of components.
Dalvik virtual machine optimized for mobile devices.
Integrated browser based on the open source WEBKIT engine.
Optimized graphics for 2D graphics library & 3D graphics based on the OpenGL ES 1.0 specification
SQLite for structured data storage.
Media support for common audio, video, and still image formats (MPEG4, H.264, MP3, AAC, AMR, JPG, PNG, GIF).
GSM Telephony (hardware dependent).
Bluetooth, EDGE, 3G, and WiFi (hardware dependent).
Camera, GPS, compass, and accelerometer (hardware dependent).
Rich development environment including a device emulator, tools for debugging, memory and performance profiling, and a plugin for the Eclipse IDE.
UPDATES
1.0:- Released 23 September 2008
1.1:- On 9 February 2009,released by T-mobile G1
1.5:- (Cupcake) Based on Linux Kernel 2.6.27 released on 30 April 2009.
1.6:- (Donut) Based on Linux Kernel 2.6.29 released on 15 september 2009.
2.0 / 2.1:- (Eclair) Based on Linux Kernel 2.6.29 released on 26 october 2009.
2.2:- (Froyo) Based on Linux Kernel 2.6.32 released on 20 may 2010.
2.3:- (Gingerbread) Based on Linux Kernel 2.6.35 release on 6 december 2010.
3.0:- (Honeycomb) to be launched soon.
SOFTWARE DEVELOPMENT KIT(SDK)
Android Software development kit(SDK) includes set of development tools these includes a debugger, libraries, a handset emulator (based on QEMO), documentation, sample code, and tutorials.
Development platforms include computers running linux , MAC OS X 10.4.9 or later, windows xp or later.
Android applications are packaged in format and stored under /data/app folder on the Android OS (the folder is accessible to root user only for security reasons).
APK package contains .dex files, resource files, etc
GRAPH OF SALES & SHARES OVER THE GLOBE
ADVANTAGES OF ANDROID OVER OTHER SMART PHONES
REMOVABLE BATTERY allowing users to secure an extra battery and swap them out.
Almost all phone have the removable SD card.
Run multiple applications .
Support apps designed for other manufacterer using ANDROID.
CHEAPER as compared to other smartphones.
disADVANTAGES OF ANDROID OVER OTHER SMART PHONES
Some phone forces to configure GMAIL account .
Does not deliver an on-screen keyboard that’s capable of supporting multiple language at a time.
Google does not support installing apps to the SD card , so developers are limited in what they can create.