Android is an operating system based on Linux that runs on mobile devices. It includes components like an operating system, middleware and key applications. The Android architecture includes an application framework that allows applications to access APIs and system services. The application lifecycle in Android involves states like active, paused and stopped. Security and permissions are an important part of the Android architecture to isolate applications.

1. Introduction to Android
 Introduction
 Android background
 Android Architecture
 Android applications
 Application Lifecycle
 APIs
 Security and permissions
 Summary
By,
Sunil D Shivanakkanavar

2. Introduction
 Android is a complete operating environment based upon the Linux v2.6
kernel.
 Initially , the deployment target for Android was the mobile-phone
arena, including smart phones, tablet pcs.
 Android is a software stack for mobile devices that includes an operating
system, middleware and key applications.
 Over the past decade , Android has matured and evolved into an extremely
reliable ,bulletproof , embedded operating platform having gone from 1.0 to
stable versions at 1.5 ,1.6 ,2.1 ,2.2 ,2.3 ,3.0 and now 4.0.
 Android has the power of full-blown computer operating system.
 It is based on the Linux open source platform and Oracle’s(formerly Sun
Microsystems) Java, one of the worlds most popular programming language.

3. Android Background
 The Android platform is the produce of Open Handset Alliance, a group of
organizations collaborating to build a better mobile phone
 Android Inc. was founded in Palo Alto, California, United States in October
, 2003 by Andy Rich, Rich Miner, Nick Sears and many more.
 Google acquired the Android Inc. in August 2005, making wholly owned
subsidiary of Google Inc.
 On November 5 2007, the Open Handset Alliance, a consortium of several
companies which include Broadcom Corporation, Google, HTC, Motorola
, Qualcomm, Samsung Electronics and many more unveiled itself.
 On the same day they released the android first product built on Linux kernel
2.6.
 Version history of Android Operating System begin with release of version 1.0
in September 2008.
 The code names were released in Alphabetic order: Cupcake ,Donut, Éclair
, Froyo , Gingerbread, Honeycomb and Ice cream sandwidth.

4. Android Architecture
 Diagram of Android Architecture is shown below:

5. Android Application Lifecycle

6. API’s
API Level is an integer value that uniquely identifies the framework API revision
offered by a version of the Android platform.
The Android platform provides a framework API that applications can use to
interact with the underlying Android system. The framework API consists of:
 A core set of packages and classes
 A set of XML elements and attributes for declaring a manifest file
 A set of XML elements and attributes for declaring and accessing resources
 A set of Intents
 A set of permissions that applications can request, as well as permission
enforcements included in the system

7. Security and Permissions
Android is a privilege-separated operating system, in which each application runs
with a distinct system identity (Linux user ID and group ID). Parts of the system are
also separated into distinct identities. Linux thereby isolates applications from each
other and from the system.

8. Summary
Andy Rubin’s creation called Android was purchased by Google in 2005 and made freely
available to developers to create mobile device applications using Java and XML. Since
then, the Android phenomenon has grown to encompass an open industry alliance of
the leading manufacturers and become the fastest growing mobile platform today. It is
the horse to bet on for the future of not only mobile devices, but also other types of
consumer electronic devices, including tablets and iTV.
In next session you will learn about the android tools and how to configure the android
tools with the eclipse .