Android OPERATING SYSTEM Overview.pdf

 Android Operating System

Yogita Pathak Department of Computer Science & Engineering

Contents 

Mobile OS

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 Android History

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 Android Versions



Models

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 Architecture

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Challenges

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Merits and Demerits

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Market Share

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Opportunities

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References

Mobile Operating System A mobile operating system (OS) is a software that allows smart phones, tablet PCs and other devices to run applications and programs. Examples Symbian OS BlackBerry OS Apple’s iOS Windows Phone OS

Android OS

History The Android™ was built upon the open Linux kernel, and developed by Android, Inc., which is owned by Google. Open Handset Alliance - to develop open standards for mobile devices

 Variety of Android

Phone

HTC G1, Droid, Tattoo

Suno S880

Motorola Droid (X)

Samsung Galaxy

Sony Ericsson

 Tablets

Velocity Micro Cruz

Dawa D7

Gome FlyTouch

Toshiba Android SmartBook

Acer beTouch

Cisco Android Tablet

 Architecture

 Applications



Android provides a set of core applications:       



Email SMS Program Calendar Maps Browser Contacts Etc

All applications are written using the Java language.

Common file structure for Apps code files

Autogenerated resource list

images UI layouts

constants

GUI

 Application Framework



Enabling and simplifying the reuse of components 

 

Developers have full access to the same framework APIs used by the core applications. Users are allowed to replace components. Each application can publish its capabilities which other apps can use

Libraries





Including a set of C/C++ libraries used by components of the Android system Exposed to developers through the Android application framework

Runtime



Core Libraries  Providing most of the functionality available in the core libraries of the Java language  APIs  Data Structures  Utilities  File Access  Network Access  Graphics etc.

Runtime 

Software Development kit (Dalvik Virtual Machine )  Providing environment on which every Android application runs  Each Android application runs in its own process, with its own instance of the Dalvik VM.  Dalvik has been written such that a device can run multiple VMs efficiently.

.dex format is optimized for minimal memory footprint.

Linux Kernel





Relying on Linux Kernel for core system services 

Memory and Process Management

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Network Stack

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Driver Model

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Security

Providing an abstraction layer between the H/W and the rest of the S/W stack

Challenges 

  





CPU typically runs 500-600 Mhz RAM available to an App may only be a few megabytes Disk (flash) access is very slow Lifecycle - apps must pause/quit often, and restore to give the illusion that they are always running UI design  typical screen may be HVGA (320x480)  may be in portrait or landscape  very high DPI - small text may not be readable  touch resolution is very low (~25 pixel) Network access may be slow and (very) intermittent

Merits Highly customizable  Services can run in the background  Notifications let you know of background events  Multitasking  Widget  Can install a modified ROM  Easy access to thousands of applications via the Google Android Android App Market  Google Maniac 

Demerits  

Advertising  Continuous Internet connection

MarketShare Feb’10

May’10

Apr’11

RIM

42.1%

41.7%

29%

Apple

25.4%

24.4%

25%

Google

9%

13%

33%

Microsoft

15.1%

13.2%

7.7%

Palm

5.4%

4.8%

2.9%

Opportunities Moving towards Home Appliances

References http://www.wisegeek.org/what-are-the-different-types-of-mobilephone-operating-systems.htm 

  http://developer.android.com/training/index.html http://developer.android.com/training/articles/security-tips.html http://android-developers.blogspot.in/ http://www.anddev.org http://www.openhandsetalliance.com/

Queries

 Thanks