The document details the history and architecture of the Android Open Source Project, originally founded as Android, Inc. in 2003 and acquired by Google in 2005. It covers key components such as the Linux kernel, hardware abstraction layer, and noteworthy features of the Dalvik VM. Additionally, it explains the structure and communication mechanisms within the Android platform, including the role of libraries and core services.

1. Mobile & Embedded Computing Lab
An deep dive into
Android Open Source Project
Siji Sunny
Director, MELabs
siji@melabs.in
Mobile : +91 9820896398
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History
● October 2003 - Android, Inc founded in California by Andy
Rubin, Rich Miner, Nick Sears and Chris White.
● The company's were to develop an advanced operating
system for digital cameras
● August 17, 2005 - Google acquired Android Inc.
● the team led by Rubin developed a mobile device platform
powered by the Linux kernel.
● October 22, 2008 - First Android device launched in the
market.
Ref: Wikipedia

3. History
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4. ● Source code available for download-Contains
- Kernel
- Native Libraries
- Android runtime
- Application Framework
● License -Android Open Source Project is the Apache
Software License, Version 2.0 (For userspace).
● Android originated by a group of companies - Open
Handset Alliance, led by Google.
● Freedom to implement your own device ?
- Google Apps are not open-source
- Vendor depended firmware/drivers
Concept- AOSP
Android Open-Source Project
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Architecture

6. Applications & Framework
Binder IPC
Linux Kernel
Hardware Abstraction Layer
Media Player
Services
Camera Service
Other Services
Window manager
Activity Manager
Notification
Manager
Other Services
System ServerMedia Server
Ref :http://s.android.com/devices/index.html
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Binder-IPC
●Driver to facilitate inter-process communication (IPC)
●Allows high level framework APIs to interact with Android's
system services
●At the application framework level, all of this communication
is hidden from the developer
●High performance through shared memory

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HAL
●User space C/C++ library layer
●Defines the interface that Android requires hardware
“drivers” to implement
●Separates the Android platform logic from the hardware
interface
Graphics Audio Camera Bluetooth
HARDWARE ABSTRATION LAYER

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Native Libraries
●Bionic Libc
●Function Libraries (For standard calls)
●Native Servers (for UI/Video/Audios)
●Hardware Abstraction Libraries
WebkitMedia Framework Sqlite Bionic Libc
OpenGL|ES Audio Manager FreeType SSL
LIBRARIES

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What is Bionic
●Custom libc implementation, optimized for embedded
use.
Why build a custom libc library?
●License: BSD License (Objective was to keep GPL out of
user-space)
●Size: will load in each process, so it needs to be small
●Fast: limited CPU power means we need to be fast
●Small size and fast code paths
●Very fast and small custom pthread implementation

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Bionic -Disadvantage
●Doesn't support certain POSIX features
●Not compatible with Gnu Libc (glibc)
●All native code must be compiled against bionic

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Dalvik Vm
● The software that runs the apps on Android devices
● It's fast, even on weak CPUs
● it will run on systems with little memory
● it will run in an energy-efficient way
● Provides application portability and runtime consistency
● Runs optimized file format (.dex) and Dalvik bytecode
● Java .class / .jar files converted to .dex at build time

13. Compiling & packaging
.java files
source code
.class file .dex file .apk file
Java compiler
javac
Dex compiler
(dx)
Packaging
(aapt)
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Android Runtime
● Bootloader
● Kernel
● Init
● Android runtime Dalvik/Zygote
● System Server
● Activity Manager
● Launcher (Home)

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Zygote Service
(Started at boot)
Zygote Dalvik VM
Process 1
Shared Memory
VM 1
Application 1 Process 2
VM 2
Application 2
Process 3
VM 3
Application 3

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Application Framework

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Core Platform Services
● Services that are essential to the Android platform
● Behind the scenes - applications typically donʼt
access them directly

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Core Platform Services
●Activity Manager
●Package Manager
●Window Manager
●Resource Manager
●Content Providers
●View System

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Hardware Services
●Telephony Service
●Location Service
●Bluetooth Service
●WiFi Service
●USB Service
●Sensor Service

20. Twitter : siji_sunny
Gtalk : sijisunny
siji@melabs.in
sijisunny@gmail.com
Thank You
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