"First and foremost, Android is a software stack for
mobile devices. This means that high on the list of priorities is
the preservation of battery power and the efficient management of
limited memory resources. There are five distinct layers to the
Android system stack:
"The Acorn RISC Machine (ARM) Linux core forms the solid base
upon which all the other layers stand. Linux is a proven technology
that is highly reliable, and the ARM processor family is known for
high performance on very low power requirements.
"The libraries provide the reusable and sharable low-level code
for basic functions such as codecs — software for coding and
decoding digital sound and video — functions for the
presentation of rich graphics on a small displays, secure shell
support for encrypted TCP/IP traffic into the cloud, as well as
component support for Web browsing (WebKit), SQL database
functionality (SQLite), and standard C library functionality you
would expect in a Linux system.
"The Dalvik run-time byte-code interpreter, which strongly
resembles the Java language byte-code interpreter, adds a few
distinct features that uniquely define the security and
power-preserving model of Android. Every application currently
running, for example, has its own user ID and its own copy of the
interpreter running to strictly separate processes for security and
reliability.
"The open source Android operating system has allowed for
sophisticated Cloud Computing applications to run wherever you are.
Designed to be highly efficient on battery-powered devices like the
T-Mobile G1 smartphone, at heart, Android is Linux.
