Presented by: Saurabh Kumar Sinha (MRT07UGBIT 186) IT VII Semester, Shobhit University Meerut

Android is a software stack for mobile devices that includes an OS, middleware and key applications. User applications can be developed using Android SDK which supplies a host of API’s needed for development using Java programming language. IT VII Semester, Shobhit University Meerut

Google acquired Android Inc.USA in 2005 with establishing OHA. Announced Android in 2007 and released source code. reached version 2.1 releasing Google’s Nexus. IT VII Semester, Shobhit University Meerut

consists of five software layers: Linux; Libraries; Runtime; Application Framework; and Applications.

Linux—the bottom layer is the Linux OS itself— version 2.6.3x.This provides process and memory management, security, networking and an array of relevant device drivers. Libraries—  reside on top of the OS.  includes Google’s version of standard C system library (libc), called bionic, and tuned for embedded Linux based devices.  media and graphics libraries and  SQLite (~500kb) IT VII Semester, Shobhit University Meerut

Runtime—  on top of the OS, is the Android runtime—the Dalvik VM.  designed specifically for Android and is register based to conserve memory and maximize performance.  separate instance of the Dalvik VM is used to execute each Android application.  The underlying OS is used for memory management and multi-threading. IT VII Semester, Shobhit University Meerut

Application framework—  provides a number of services to apps implemented as Java classes.  Any application can “publish” its capabilities for use by other Applications—  , SMS, calendar, contacts and Web browser.  Applications are written in Java.  processed with the standard Java tools with a converter being used to translate to the Dalvik VM byte codes. SQLite:  powerful and lightweight(approx.225kb) relational database engine (RDBMS).  SQLite library is linked in an application program.  The library can be called dynamically. IT VII Semester, Shobhit University Meerut

An Eclipse-based development environment is available from Google. An Android application consists of a number of resources that are bundled into an archive, an Android package. There is no single entry point to a program (like main()) IT VII Semester, Shobhit University Meerut

There are three types of components which are instantiated and run as required :  Activities: an executable unit that performs a specific function and has a user interface.  Services: no user interface and runs in the background.  Broadcast receivers: respond to system wide messages issued by other applications or the OS. IT VII Semester, Shobhit University Meerut

simple Java interpreter machine, developed to run on low- end memory mobile devices. capability to run along an application compilation enhancing the runtime performance of the applications. DRAWBACKS: – none-compatibility with Java SE libraries, Java ME class libraries and Swing Java libraries. MERITS: – minimal-electrical power consumption. – vast library resources. – assures the open source status of Android since Android uses a Java Virtual execution environment developed by Google. IT VII Semester, Shobhit University Meerut

Android is a multi-process system, in which each application runs in its own process. Most security at the process level through standard Linux facilities. Additional securities through “permission” mechanism that enforces restrictions on the specific operations that a particular process can perform. In Android security architecture no application, by default, has permission to perform any operations that would adversely impact other applications, the OS, or the user. This includes reading or writing the user’s private data, reading or writing another application’s files, performing network access. IT VII Semester, Shobhit University Meerut

OHA - Open Handset Alliance  a consortium of several companies including  HTC, Intel, LG, Motorola, NVIDIA, Samsung, T-Mobile, Google and so on.  Established by Google after acquiring Android Inc., California,USA.  Declared Android open source. IT VII Semester, Shobhit University Meerut

From Gizmodo's Learn Android isandroid.html Introduction to Android by Jason Chen who is developer advocate at Google IT VII Semester, Shobhit University Meerut

THANK YOU!