Android

What is that?!?!

Well,
Android is a mobile operating system initially developed by Android Inc. Android was purchased by Google in 2005. Unit sales for Android OS Smartphone ranked first among all Smartphone OS handsets sold in the U.S. in the second and third quarters of 2010!!

Android relies on Linux version 2.6 for core system services such as security, memory management, process management, network stack, and driver model. The kernel also acts as an abstraction layer between the hardware and the rest of the software stack.

The following diagram shows the major components of the Android operating system…

Underlying all applications is a set of services and systems, including:

• A rich and extensible set of Views that can be used to build an application, including lists, grids, text boxes, buttons, and even an embeddable web browser
• Content Providers that enable applications to access data from other applications (such as Contacts), or to share their own data
• A Resource Manager, providing access to non-code resources such as localized strings, graphics, and layout files
• A Notification Manager that enables all applications to display custom alerts in the status bar
• An Activity Manager that manages the lifecycle of applications and provides a common navigation backstack

Android includes a set of core libraries that provides most of the functionality available in the core libraries of the Java programming language. Every Android application runs in its own process, with its own instance of the Dalvik virtual machine. Dalvik has been written so that a device can run multiple VMs efficiently. The Dalvik VM executes files in the Dalvik Executable (.dex) format which is optimized for minimal memory footprint. The VM is register-based, and runs classes compiled by a Java language compiler that have been transformed into the .dex format by the included “dx” tool. The Dalvik VM relies on the Linux kernel for underlying functionality such as threading and low-level memory management.

 

The Android OS can be used as an operating system for cell phones, netbooks and tablet PCs, including the Dell Streak, Samsung Galaxy Tab and other devices. The world’s first TV running Android, called Scandinavia. The first commercially available phone to run the Android operating system was the HTC Dream, released on 22 October 2008.

Android has a large community of developers writing application programs (“apps“) that extend the functionality of the devices. There are currently over 100,000 apps available for Android. Android Market is the online app store run by Google. By providing an open development platform, Android offers developers the ability to build extremely rich and innovative applications. Developers are free to take advantage of the device hardware, access location information, run background services, set alarms, add notifications to the status bar, and much, much more.

Useful Videos

Android Overview

Android 2.2

Android 2.3 (latest version)

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