Sequent InfoSystems Official Blog: Android overview

ANDROID

Android is a software stack for mobile devices that includes an operating system, middleware and key applications. In July 2005, Google, co-founder with Andy Rubin who is now the director of mobile platforms at Google, started up Android Inc.

ANDROID ARCHITECTURE:

· Linux Kernel

Android uses a heavily modified GNU/Linux kernel version 2.6 to provide an abstraction layer between the hardware and the rest of the software stack. It also includes many enhancements and modifications.

· Android Runtime

A vital component in the Android stack which is composed of two major parts:

o The Dalvik virtual machine: One of the most important components in Android which is designed to run on a limited CPU and RAM (250-500MHz) (20-40 MB), an OS with no swap space and on a device with limited power

o Core libraries: Android's core libraries provide most of the functionality available in the core libraries of Java needed for applications development.

· Native Libraries

This layer, which is implemented in C/C++, houses the core libraries providing the bulk of Android functionalities: C library, SQLite, Surface management, OpenGL, Media Framework, Audio Manager

· Application Framework

This is a general purpose toolkit that all applications use. It is written in Java language to enable reusability and replacement of components.

· Applications

There is a bundle of core applications coming along with Android such as: email client SMS program, calendar, maps, browser, contacts … and thousands of useful applications on the Android market.

Figure 1: major components of the Android operating system.

OS COMPARISON:

	Android	Window Mobile 7	iOS	RIM	Symbian
Developer	Google	Microsoft	Apple	Blackberry	Nokia
Copy/Paste	✔	✘	✔	✔	✔
Multitasking	✔	✘	✔	✔	✔
Flash Support	✔	✘	✘	✘	✔
Silverlight Support	✘	✘	✘	✘	✘
HTML5 Support	✔	✘	✔	✔	✘
Unified Inbox	✔	✘	✔	✔	✔
Exchange Support	✔	✔	✔	✔	✔
Threaded Email	✔	✘	✔	✔	✔
Visual Voice Chat	✔	✘	✔	✔	✔
Video Calling	✔ Third Party	✘	✔	✔	✔
Universal Search	✔	✘	✔	✔	✔
Internet Tethering	✔	✘	✔	✔	✔
Removable Storage	✔	✘	✘	✔	✔
Facebook Integration	✔(Third Party Integration)	✔	✘(Third Party App)	✔	✔
Twitter Integration	✔(Third Party Integration)	✘	✘(Third Party App)	✔	✔
Folders	✔	Hubs	✔	✔	✔
Apps Organization	Customizable	Alphabetical	Customizable	Customizable	Customizable
App Store	90,000+ Apps	1,000+ Apps	300,000+ Apps	✔	✘
Microsoft Office Support	Third Party App	Built-in	Third Party App	Third Party App	Third Party App
Widgets	✔	Tiles on Home Screen	✘	✔	✔
Media Sync	Direct File Transfer + Third Party Software	Zune Software Mac & PC	iTunes Mac & PC	✔	✔
X-Box Live Integration	Via Third Party App	Built-in	Via Third Party App	Via Third Party App	Via Third Party App