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Motivation Most Popular OS for mobile platform

Powers more than a Billion phones and tabletsaround the world!

About 1.5 Million new devices running android areactivated daily!

Revolutionized the mobile phone industry

There is a need to know about the Operation andother Technical aspects of the Android OS

Above all, Its free.

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Overview

The Big Picture

Linux Kernel

Binder Driver

Power Management

Android Run Time

Dalvik Virtual Machine

Other Services and Peripherals

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The Big Picture

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The Linux Kernel

Android is built on the Linux kernel, but Android is not

Based on Linux Kernel v3.4

No Native windowing system

No glibc (GNU C Library) Support

Does not include full set of standard Linux Utilities

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Binder Driver Driver to facilitate IPC (Inter Process Communication

between applications and services

Problems of Linux IPCo Applications and services may run in separate processes but must commu

and share data

o IPC can introduce significant processing overhead and security holes

Properties of Bindero High performance through Shared Memory

o Per-process thread pool for processing requests

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Binder in Action!

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Power Management

Mobile devices depend on battery power and batte

limited capacity

Properties of Power Managemento Built on top of standard Linux Power Management

o Supports more aggressive power management policy

o Components make requests to keep the power on through Wake Locks

If there is no active Wake Lock, CPU will be turned o

Use Wake Locks carefully!

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Power Management in Action

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Why Linux Kernel?

Relies on Linux Kernel for core system serviceso Memory and Process Management

o Network stack

o Driver model

o Security

Support for shared libraries

Its already Open Source!

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Android Run Time

Core Libraries and Dalvik Virtual Machine

Core Librarieso Provides most of the functionality available in the core

libraries of the Java language

o APIs, Data Structures, File Access, Network Access, Etc..

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Dalvik VM

Androids custom implementation of Virtual Machine

Register Architecture

It is a Virtual Machine too Run on a slow CPU

o With relatively little RAM

o On an OS without Swap space

o And most importantly for devices powered by Battery!

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Why DVM?

Provides Application Portability and Runtime

consistency

Designed for Embedded Environment

o Supports multiple virtual machine processes per device

o Highly CPU-optimized byte code interpreter

o Uses runtime memory very efficiently

Runs optimized file format (.dex) and Dalvik bytecode

Java .class/.jar files converted to .dex at build time

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Other Services and Peripheral

Native libraries

Application Framework

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Application Layer Application Layer

Top most layer of the Android stack All Applications such as SMS client, Dialer, Web

Browser, contact manager run in this layer

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Future Work: Android ART

Android ART is a new experimental runtime implementedin v4.4 (KitKat) that executes application instructions

Dalvik VMJust-In-Time or JIT Compiler

ART- Ahead-of-Time or AOT Compiler

Byte code is precompiled into machine language at the

time of installation!

Reported great increase in performance and battery life

May completely replace Dalvik in the future!

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Few Drawbacks!

Fragmentation

Decentralization

Unstable, Hangs if the load is more

Battery Draining and Overheating

Continuous Internet Connection

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References[1] Benjamin Speckmann, The Android mobile platform, MS.Thesis, Depart. comp. science, EUniv., Michigan, US, 2008.

[2] Benny Skogberg Android Application Development, MS.Thesis, Depart. Comp. Science, M2010.

[3] Chien-Wei Chang, Chun-Yu Lin, Chung-Ta King,Implementationof JVM Tool Interface on DaMachine,paperappears in (VLSI-DAT), 2010 International Symposium on Digital Object Identif

[4] Bimal Gadhavi & Khushbu Shah, Analysis of the Emerging Android Market , Project ReporSanJos State University May 2010

[5] Stefan Brahler, Analysis of android architecture, Department of computer science, Karlsrutechnologies, Germany, june 2010

[6] Marakana,AndroidBootcamp TrainingCourse http://marakana.com/training/android/and18 Oct, 2012.

[7] Google I/O: Anatomy and Physiology of Android by Patrick Brady

[8] Google I/O: Dalvik Virtual Machine Internals by Dan Bornstein

[9] Vaibhav Kumar, Vinod Kumar, Sarkania et al., International Journal of Advanced Research and Software Engineering 3(6), June - 2013, pp. 143-17

[10] Android Home Page: http://android.com

http://android.com/http://android.com/

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Thank YouHappy Learning!

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Questions?