Android is an operating system for mobile
devices such as cellular phones, tablet
computers and net books.
It was initially developed by Android Inc.
which was later purchased by Google.
Google further formed the open handset
Open Handset Alliance
The Open Handset Alliance (OHA) is a business
alliance of 78 firms for developing
open standards for mobile devices
Technically the term “ OPEN STANDARDS “ refers
to a specification whose description is freely
This means that developers are free to create
applications which are valid according to the
specification and which will therefore work with
software designed for it.
Some major names in OHA
Android is open source.
The source code of the android operating system is
freely available to anyone.
Being an open source it has the following
Android relies on Linux version 2.6 for core system
services such as security, memory management,
process management, network stack, and driver
The kernel also acts as an abstraction layer between
the hardware and the rest of the software stack.
Dalvik Virtual Machine
The Dalvik VM takes the generated Java class files and
combines them into one or more Dalvik executable
It reuses duplicate information from multiple class
files, effectively reducing the space requirement
(uncompressed) by half from a traditional .jar file.
For example, the.dex file of the web browser app in
Android is about 200K, whereas the equivalent
uncompressed .jar version is about 500K.
Second, Google has fine-tuned the garbage collection
in the Dalvik VM.
Finally, the Dalvik VM uses a different kind of
assembly-code generation, in which it uses registers as
the primary units of data storage instead of the
stack.30 % fewer instructions are accomplished as a
We should point out that the final executable code in
Android, as a result of the Dalvik VM, is based not on
Java byte code but on .dex files instead.
Google android operating system can be used in
net books :
Net books are now the fastest growing segment of the
PC market, they are portable, functional and
comparatively inexpensive. It would make easier for
users of Android powered phones to share information
Virtual qwerty with SWYPE technology
This application produces a virtual
qwerty for the user
It has an additional feature that you don’t have to lift
your finger from the screen in order to type a word
The word is automatically guessed, based upon the
characters travelled across
Android is a big revolution in the field of operating
Its custom virtual machine optimize memory and
hardware resources in a mobile environment. It can be
liberally extended to incorporate new cutting edge
technologies as they emerge.
The open source platform will continue to evolve as the
developer community works together to build
innovative mobile applications.