Open Handset Allianceentire source code (including Google published the (OHA), a business alliance of 79 firms for developing open standardsan Apache The first commercially stacks) under for mobile network and telephonyphone to run the Android GOOGLE acquired Android Inc., a small startup devicesPalo formed. was was company based inLicense. California, USA. operating systemAlto, releasedJuly November September October2005 2007 2008 2008
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N DEFINITIAndroid is a mobile operating basedupon a modified version of the Linuxkernel.
CONNECTIVITY MISCELLANEOUS DEVELOPMENT Google provides a deviceAndroid has approximately 3,10,000 SP H.263 H.264 AVC MPEG-4 emulator, tools for 3GPP 3GPP 3GPPapplications available for download. MPEG-4 MPEG-4 debugging, memory and MEDIA performance profiling.FEATURESAndroid has native support for multi- BMP PNGtouch JPEG GIF The integrated development environment (IDE) is provided in AndroidEclipse by tethering, Android supports using the which allows a phoneAACbe used asTools (ADT) to LC/LTP AMR-NB Development a wireless/wired MIDI hotspotHE-AACv1 Plugin. AMR-WB Ogg HE-AACv2 MP3 WAVE
ARM Native Code CODE C++ (Library) C (Core) NATIVE Java (UI)
Applications are the process through whichuser give instructions to the system toaccomplish task and obtain results.Android applications can consist of fourcomponents:- • Activities • Services • Broadcast Receivers • Content providersApplications are saved with extension .apk .Android applications are written in the Javaprogramming language .
• Application framework provides the resources required for working of the applications.• Framework is designed to simplify the reuse of components; any application can publish its capabilities and any other application may then make use of those capabilities (subject to security constraints enforced by the framework).• Framework is designed in the same hierarchy as the java development kit.• It is available to developers in android software development kit.
Android includes a set of C/C++ libraries used by various components of theAndroid system. These capabilities are exposed to developers through theAndroid application framework. It has following components:-• System C library – It manages access to the display the standard• Surface Manager– A BSD-derived implementation ofsubsystem. C system library (libc).• Webkit – A modern web browser engine which powers both the Android• browser and an embeddable on PacketVideos OpenCORE; the libraries Media Libraries – It is based web view. support audio, video and image files.• FreeType - Bitmap and vector font rendering.• SGL - The underlying 2D graphics engine.• SQLite - A powerful and lightweight relational database engine available to all applications.
• Android relies on Linux version 2.6 for core system services.• The kernel also acts as an abstraction layer between the hardware and the rest of the software stack.• Android is not linux because it does not implements some of the stand feature and protocols of linux.• It uses permission based security model.• Special features like OOM, wakelock have been added to kernel by google.
A virtual machine (VM) is a software implementation of a machine (i.e. a computer) that executes programs like a physical machine.
TYPES OF VIRTUAL MACHINE System Process Virtual Machine
It Can run on slow CPU, with little ram & in OS with lesser or even without swap space It is optimized to use less space The interpreter is simplified for faster execution Dalvik (Register based) take average 47 % less executed VM instruction then JVM (Stack based).