What is Android OS?
By: Alodia Phan 
– jcyberinux.com
Android OS is an operating system for mobile devices (such as smart phones and tablet pc/computers). Android OS is developed by the Open Handset Alliance led by Google.
Android’s kernel is a fork of the Linux Kernel, and the said architecture has further changes made by Google. Android relies on Linux version 2.6 for core system services for security, memory management, process management, network stack, and driver model. The kernel also acts as an abstraction layer between the hardware and to the software stack(s).
The Android OS used Android SDK that provides the tools and APIs necessary to begin development of applications for Android platform by using Java programming language. Android used a set of core libraries that offers most of the functionality, be available in the core libraries of the Java Programming Language. Every Android application runs in its own process, within the own instance of the Dalvik virtual machine. Dalvik has been written so that a device can invoke multiple Virtual Machines’ more efficiently.
The Dalvik VM runs files in the Dalvik Executable (.dex) format, for optimization and minimal memory footprint. The VM is register-based, and runs classes compiled by a Java language compiler, and transformed into the .dex format by the included “dx” tool. The Dalvik VM relies on the Linux kernel, for functionality such as threading and low-level memory management. Android will ship with a set of core applications including an email client, SMS program, calendar, maps, browser, contacts, and others. All applications are written using the Java programming language. (To learn more click here)
