Android Operating System

Under the Guidance of
Prof. Y. S. KALE
Submitted By:
SUNIL MAURYA
B-TECH SEM VIII, COMP-II, Roll No. 22
DEPARTMENT OF COMPUTER ENGINEERING
BHARTI VIDYAPEETH COLLEGE OF ENGINEERING,
PUNE

Outlines
1. Introduction
2. Platform
3. Process Scheduling
4. Software development & SDK
5. Overall evaluation
SUNIL MAURYA COMP-II Roll No 22
2

What is Android?
A complete software stack for mobile devices.
Android is
A first joined project of the Open Handset Alliance (OHA).
It’s a First open, complete and free platform
Its Software stack is open-sourced and licensed under Apache 2.0
In Android Source code will be available to everyone and anyone will have the capability to built an image
The Android platform
includes an operating system, a middleware and some applications.
Android is very Lightweight and fully featured
Developers can extend and replace existing components
A generous development environment
A SDK is available to build, compile, test and debug user applications.
Applications are developed using Java programming language
No difference between the built-in applications and the user ones
3

Introduction
What is the Open Handset Alliance (OHA)?
->It's a consortium of several companies
4

Introduction
What is the Open Handset Alliance (OHA)?
Devoted to advancing open standards for mobile devices
Develop technologies that will significantly lower the cost of developing and distributing mobile devices and services
5

Versions
6

7
Versions
The most recent released versions of Android are:
2.0/2.1 (Eclair), which revamped the user interface and introduced HTML5 and Exchange ActiveSync 2.5 support
2.2 (Froyo), which introduced speed improvements with JIT optimization and the Chrome V8 JavaScript engine
2.3 (Gingerbread), which refined the user interface, improved the soft keyboard and copy/paste features, and added support for Near Field Communication
3.0 (Honeycomb), a tablet-orientedrelease which supports larger screen devices and introduces many new user interface features, and supports multicore processors and hardware acceleration for graphics.[The upcoming version of Android is:
Ice Cream Sandwich,[a combination of Gingerbread and Honeycomb into a "cohesive whole,"with a possible release in mid-2011.

Smart phone market
8

Platform
Operating System
Android uses Linux for its device drivers, memory management, process management, and networking.

The next level up contains the Android native libraries. They are all written in C/C++ internally, but you’ll be calling them through Java interfaces. In this layer you can find the Surface Manager, 2D and 3D graphics, Media codecs, the SQL database (SQLite), and a native web browser engine (WebKit).

Dalvik Virtual Machine. Dalvik runs dex files, which are converted at compile time from standard class and jar files.
9

Platform
Network Connectivity
It supports wireless communications using:
GSM mobile-phone technology
3G
Edge
802.11 Wi-Fi networks
10

Android has many components
11

Android applications have common structure
Views such as lists, grids, text boxes, buttons, and even an embeddable web browser
An Activity Manager that manages the life cycle of applications and provides a common navigation backstack
A Notification Manager that enables all apps to display custom alerts in the status bar
Content Providers that enable applications to access data from other applications (such as Contacts), or to share their own data
A Resource Manager, providing access to non-code resources such as localized strings, graphics, and layout files
12

Android applications have common structure
Broadcast receivers can trigger intents that start an application
Activity is the presentation layer of your app: there will be one per screen, and the Views provide the UI to the activity
Data storage provide data for your apps, and can be shared between apps – database, file, and shared preferences (hash map) used by group of applications
Intents specify what specific action should be performed
Services run in the background and have no UI for the user – they will update data, and trigger events
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There is a common file structure for applications
code
Autogenerated resource list
files
images
UI layouts
constants
14

Intent provides late running binding to other apps
It can be thought of as the glue between activities. It is basically a passive data structure holding an abstract description of an action to be performed.
Written as action/data pairs such as:
VIEW_ACTION/ACTION content://contacts/1
15

Services declared in the manifest and provide support
Services run in the background:
Music player providing the music playing in an audio application
Intensive background apps, might need to spawn their own thread so as to not block the application
16

Notifications let you know of background events
This way you know that an SMS arrived, or that your phone is ringing, and the MP3 player should pause
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Content Providers share data
You need one if your application shares data with other applications
This way you can share the contact list with the IM application
If you don’t need to share data, then you can use SQLlite database
18

UI layouts are in Java and XML
setContentView(R.layout.hello_activity); //will load the XML UI file
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Security in Android follows standard Linux guidelines
Each application runs in its own process
Process permissions are enforced at user and group IDs assigned to processes
Finer grained permissions are then granted (revoked) per operations
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.google.android.app.myapp" >
<uses-permission id="android.permission.RECEIVE_SMS" />
</manifest>
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Performance

21

Android Runtime
22

Platform initialization
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Priorities: Android 2.2 Scheduling
• Static priority
The maximum size of the time slice a process should be allowed
before being forced to allow other processes to compete for the
CPU.
• Dynamic priority
The amount of time remaining in this time slice; declines with
time as long as the process has the CPU.
When its dynamic priority falls to 0, the process is marked for
rescheduling.
• Real-time priority
Only real-time processes have the real-time priority.
Higher real-time values always beat lower values
Android – process priority is dynamic. Scheduler increases/decreases the priority.
24

Android Scheduling
Process Selection
A process’s scheduling class defines which algorithm to apply
most deserving process is selected by the scheduler
real time processes are given higher priority than ordinary processes
when several processes have the same priority, the one nearest the front of the run queue is chosen
when a new process is created the number of ticks left to the parent is split in two halves, one for the parent and one for the child
priority and counter fields are used both to implement time-sharing and to compute the process dynamic priority
25

Android makes mobile Java easier
Well, sort of…
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Android applications are written in Java
package com.google.android.helloactivity;
import android.app.Activity;
import android.os.Bundle;
public class HelloActivity extends Activity {
public HelloActivity() {
}
@Override
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
setContentView(R.layout.hello_activity);
}
}
27

Android applications are compiled to Dalvik bytecode
Linux OS
Loaded into Dalvik VM
Write app in Java
Compiled in Java
Transformed to Dalvik bytecode
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Android has a working emulator
29

Software development
Development requirements
Java
Android SDK
Eclipse IDE (optional)

30

Software development (Contd..)
IDE and Tools

Android SDK
Class Library
Developer Tools
dx – Dalvik Cross-Assembler
aapt – Android Asset Packaging Tool
adb – Android Debug Bridge
ddms – Dalvik Debug Monitor Service
Emulator and System Images
Documentation and Sample Code
Eclipse IDE + ADT (Android Development Tools)
Reduces Development and Testing Time
Makes User Interface-Creation easier
Makes Application Description Easier

31

Overall evaluation
Advantages

There are a host of advantages that Google’s Android will derive from being an open source software. Some of the advantages include:
The ability for anyone to customize the Google Android platform
The consumer will benefit from having a wide range of mobile applications to choose from since the monopoly will be broken by Google Android
We will be able to customize a mobile phones using Google Android platform like never before
Features like weather details, opening screen, live RSS feeds and even the icons on the opening screen will be able to be customized
In addition the entertainment functionalities will be taken a notch higher by Google Android being able to offer online real time multiplayer games

32

Overall evaluation
Limitations

Bluetooth limitations
Android doesn't support:
Bluetooth stereo
Contacts exchange
Modem pairing
Wireless keyboards

But it'll work with Bluetooth headsets, but that's about it
Firefox Mobile isn't coming to Android
Apps in Android Market need to be programmed with a custom form of Java
-> Mozilla and the Fennec won't have that

33

Platform
Future possibilities
Google Android Sales to Overtake iPhone in 2012
The OHA is committed to make their vision a reality: to deploy the Android platform for every mobile operator, handset manufacturers and developers to build innovative devices
Intel doesn’t want to lose ownership of the netbook market, so they need to prepare for anything, including Android
Fujitsu launched an initiative to offer consulting and engineering expertise to help run Android on embedded hardware, which aside from cellphones, mobile internet devices, and portable media players, could include GPS devices, thin-client computers and set-top boxes.
More Android devices are coming and some will push the envelope even further

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Conclusion
We can only hope that the next versions of Android have overcome the actual limitations and that the future possibilities became a reality
There are lots of sources of information
The sdk comes with the API references, sample applications and lots of docs
Blog http://android-developers.blogspot.com/ which has lots of useful examples, details
There is http://www.anddev.org
35

QUESTIONS?
36

THANK YOU!
37

Android Operating System

by Sunil Maurya on Jun 11, 2011

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Android Operating System Presentation Transcript