Android Devices in the Market

• Smartphones

• Tablets

• Laptops

• Notebooks

• E-book Reader

• Smart TVs ( Google TVs)

Then OS has seen in

• Niche applications on wristwatches

•  Headphones

• Car CD and DVD players

• Smart glasses(Project Glass)

•  Refrigerators

• Vehicle satnav systems

• Home automation systems

• Games consoles

• Mirrors

• Cameras

• Portable Media Players

• Landlines

• Treadmills... etc,..

Architecture of Android

In order to understand how Android works, take a look at given below Figure, which shows the various layers that make up the Android operating system (OS).

The Android OS is roughly divided into five sections in four main layers:

➤ Linux kernel             — This is the kernel on which Android is based. This layer contains all the lowlevel device drivers for the various hardware components of an Android device.

➤ Libraries                   — These contain all the code that provides the main features of an Android OS. For example, the SQLite library provides database support so that an application can use it for
data storage. The WebKit library provides functionalities for web browsing.

➤ Android runtime          — At the same layer as the libraries, the Android runtime provides a set of core
libraries that enable developers to write Android apps using the Java programming language. The
Android runtime also includes the Dalvik virtual machine, which enables every Android application
to run in its own process, with its own instance of the Dalvik virtual machine (Android
applications are compiled into the Dalvik executables). Dalvik is a specialized virtual machine
designed specifically for Android and optimized for battery-powered mobile devices with limited
memory and CPU.

➤Application framework   — Exposes the various capabilities of the Android OS to application
developers so that they can make use of them in their applications.

➤ Applications                    — At this top layer, you will find applications that ship with the Android device (such as Phone, Contacts, Browser, etc.), as well as applications that you download and install
from the Android Market. Any applications that you write are located at this layer.

Features of Android

As Android is open source and freely available to manufacturers for customization, there are no fixed
hardware and software configurations.

 However, Android itself supports the following features:

➤ Storage              —     Uses SQLite, a lightweight relational database, for data storage. Chapter 6 discusses  data storage in more detail.

➤ Connectivity      — Supports GSM/EDGE, IDEN, CDMA, EV-DO, UMTS, Bluetooth (includes
A2DP and AVRCP), WiFi, LTE, and WiMAX. Chapter 8 discusses networking in more detail.

➤ Messaging         — Supports both SMS and MMS. Chapter 8 discusses messaging in more detail.

➤ Web browser      — Based on the open-source WebKit, together with Chrome’s V8 JavaScript engine

➤ Media support    — Includes support for the following media: H.263, H.264 (in 3GP or MP4
container), MPEG-4 SP, AMR, AMR-WB (in 3GP container), AAC, HE-AAC (in MP4 or
3GP container), MP3, MIDI, Ogg Vorbis, WAV, JPEG, PNG, GIF, and BMP

➤ Hardware support — Accelerometer Sensor, Camera, Digital Compass, Proximity Sensor,
and GPS

➤ Multi-touch            — Supports multi-touch screens

➤ Multi-tasking         — Supports multi-tasking applications

➤ Flash support          — Android 2.3 supports Flash 10.1.

➤ Tethering                 — Supports sharing of Internet connections as a wired/wireless hotspot

What Is Android?

Android is a mobile operating system that is based on a modified version of Linux. It was originally
developed by a startup of the same name, Android, Inc. In 2005, as part of its strategy to enter the
mobile space, Google purchased Android and took over its development work (as well as its development team).

Google wanted Android to be open and free; hence, most of the Android code was released under
the open-source Apache License, which means that anyone who wants to use Android can do so by
downloading the full Android source code. Moreover, vendors (typically hardware manufacturers)
can add their own proprietary extensions to Android and customize Android to differentiate their
products from others. This simple development model makes Android very attractive and has thus
piqued the interest of many vendors. This has been especially true for companies affected by the phenomenon

of Apple’s iPhone, a hugely successful product that revolutionized the smartphone industry.
Such companies include Motorola and Sony Ericsson, which for many years have been developing
their own mobile operating systems. When the iPhone was launched, many of these manufacturers
had to scramble to find new ways of revitalizing their products. These manufacturers see Android as
a solution — they will continue to design their own hardware and use Android as the operating system
that powers it.

The main advantage of adopting Android is that it offers a unified approach to application development.
Developers need only develop for Android, and their applications should be able to run on numerous
different devices, as long as the devices are powered using Android. In the world of smartphones, applications are the most important part of the success chain. Device manufacturers therefore see Android as their best hope to challenge the onslaught of the iPhone, which already commands a large base of applications.

Android Versions

Android has gone through quite a number of updates since its first release. Table 1-1 shows the various
versions of Android and their codenames.


Tab le 1-1: A Brief History of Android Versions


Android Version                   ReleaseDate                                                Codename

1.1 9                                    February 2009                                                  -

1.5 30                                  April 2009                                                      Cupcake
 
1.6 15                                  September 2009                                              Donut

2.0/2.1                                 26 October 2009                                            Eclair

2.2                                        20 May 2010                                                   Froyo

2.3                                        6 December 2010                                       Gingerbread

3.0                                        Unconfirmed at the time of writing           Honeycomb

4.0                                        November 14, 2011                                IceCream Sandwich

4.1                                         June 27, 2012                                                 Jelly Bean