Android mobile operating system Ppt

Mobile Operating System

Presented by:YOGENDRA KUMAR SAHU(2010IT071089)

IT VI SEM. JABALPUR ENGG. COLLEGE

What is Android?

• Android is a software stack for mobile devices that includes an OS, middleware and key applications.

• User applications can be developed using Android SDK which supplies a host of API’s needed for development using Java programming language.


A slice of history

• Google acquired Android Inc.,USA in 2005 with establishing OHA.

• Announced Android in 2007 and released source code.

• reached version 2.1 releasing Google’s Nexus.


The architecture

• consists of five software layers: 1) Linux;2) Libraries; 3) Runtime;4) Application Framework; and 5) Applications.


The architecture• Linux—the bottom layer is the Linux OS itself

—version 2.6.3x .This provides process and memory management, security, networking and an array of relevant device drivers.

• Libraries— reside on top of the OS. includes Google’s version of standard C system library

(libc), called bionic, and tuned for embedded Linux-based devices.

media and graphics libraries and SQLite (~500kb)


The architecture• Runtime—

on top of the OS, is the Android runtime—the Dalvik VM.

designed specifically for Android and is register based to conserve memory and maximize performance.

separate instance of the Dalvik VM is used to execute each Android application.

The underlying OS is used for memory management and multi-threading.

• Application framework— provides a number of services to apps implemented as Java

classes. Any application can “publish” its capabilities for use by other

applications.


The architecture• Applications—

email, SMS, calendar, contacts and Web browser. Applications are written in Java. processed with the standard Java tools with a converter

being used to translate to the Dalvik VM byte codes.

• SQLite: powerful and lightweight (approx.225kb) relational

database engine (RDBMS). SQLite library is linked in an application program. The library can be called dynamically. The app program uses SQLite’s functionality through

simple function calls which are more efficient than IPC. The entire database is stored as a single cross-platform

file on the device.

• IT VI SEM. JABALPUR ENGG. COLLEGE

Application development

• An Eclipse-based development environment is available from Google.

• An Android application consists of a number of resources that are bundled into an archive, an Android package.

• There is no single entry point to a program (like main()).


Application development• There are four types of components which are

instantiated and run as required : Activities: an executable unit that performs a specific

function and has a user interface. Services: no user interface and runs in the background.

Broadcast receivers: respond to system wide messages issued by other applications or the OS.

Content providers: make data available to other applications


Advantages of Dalvik Virtual Machine

• simple Java interpreter machine, developed to run on low-end memory mobile devices.

• capability to run along an application compilation enhancing the runtime performance of the applications.

• DRAWBACKS:– none-compatibility with Java SE libraries, Java ME class libraries

and Swing Java libraries.

• MERITS:– minimal-electrical power consumption.– vast library resources.– assures the open source status of Android since Android uses a Java

Virtual execution environment developed by Google.


Advantages of Dalvik Virtual Machine


Security and permissions • Android is a multi-process system, in which each application

runs in its own process. • Most security at the process level through standard Linux

facilities.• Additional securities through “permission” mechanism that

enforces restrictions on the specific operations that a particular process can perform.

• In Android security architecture no application, by default, has permission to perform any operations that would adversely impact other applications, the OS, or the user.

• This includes reading or writing the user’s private data,reading or writing another application’s files, performing network access.


Interesting Android links:• From Gizmodo'shttp://gizmodo.com/5395801/android-20-review-almost-human• Learn Androidhttp://developer.android.com/guide/basics/what-is-

android.html• Introduction to Android by Jason Chen who is developer

advocate at Googlehttp://www.youtube.com/watch?v=x1ZZ-R3p_w8


About OHA:• OHA - Open Handset Alliance• a consortium of several companies including

HTC,Intel,LG,Motorola,NVIDIA,Samsung,T-Mobile, Google and so on.

• Established by Google after acquiring Android Inc.,California,USA.

• Declared Android open source.


THANK YOU!


Android mobile operating system Ppt

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