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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/8/10/2019 Technical Presentation [Autosaved]
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Thank YouHappy Learning!
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Questions?
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