A deep dive into Android OpenSource Project(AOSP)
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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.
A deep dive into Android OpenSource Project(AOSP)
- 1. Mobile & Embedded Computing Lab An deep dive into Android Open Source Project Siji Sunny Director, MELabs siji@melabs.in Mobile : +91 9820896398 www.melabs.in
- 2. www.melabs.in 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
- 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 www.melabs.in
- 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 www.melabs.in
- 7. www.melabs.in 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
- 8. www.melabs.in 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
- 9. www.melabs.in 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
- 10. www.melabs.in 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
- 11. www.melabs.in Bionic -Disadvantage ●Doesn't support certain POSIX features ●Not compatible with Gnu Libc (glibc) ●All native code must be compiled against bionic
- 12. www.melabs.in 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) www.melabs.in
- 14. www.melabs.in Android Runtime ● Bootloader ● Kernel ● Init ● Android runtime Dalvik/Zygote ● System Server ● Activity Manager ● Launcher (Home)
- 15. www.me-labs.com 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
- 17. www.melabs.in Core Platform Services ● Services that are essential to the Android platform ● Behind the scenes - applications typically donʼt access them directly
- 18. www.melabs.in Core Platform Services ●Activity Manager ●Package Manager ●Window Manager ●Resource Manager ●Content Providers ●View System
- 19. www.melabs.in 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 www.melabs.in