Understanding Android - Practical Mobile Forensics - page 204

The Android model
To effectively understand the forensic concepts of Android, it would be helpful to have a
basic understanding of the Android architecture. Just like a computer, any computing sys-
tem that interacts with the user and performs complicated tasks requires an operating sys-
tem to handle the tasks effectively. This operating system (whether it's a desktop operating
system or a mobile phone operating system) takes the responsibility to manage the re-
sources of the system and to provide a way for the applications to talk to the hardware or
physical components to accomplish certain tasks. Android is currently the most popular
mobile operating system designed to power mobile devices. You can find out more about
this at http://developer.android.com/about/index.html . Android is open source and the code
is released under Apache license. Practically, this means anyone (especially device manu-
facturers) can access it, freely modify it, and use the software according to the requirements
of any device. This is one of the primary reasons for its wide acceptance. Notable players
that use Android include Samsung, HTC, Sony, LG, and so on.
As with any other platform, Android consists of a stack of layers running one above the
other. To understand the Android ecosystem, it's essential to have a basic understanding of
what these layers are and what they do. The following figure summarizes the various layers
involved in the Android software stack ( https://viaforensics.com/wp-content/uploads/2009/
08/Android-Forensics-Andrew-Hoog-viaForensics.pdf ):
Android architecture
Each of these layers performs several operations that support specific operating system
functions ( http://www.android-app-market.com/android-architecture.html ). Each layer
provides services to the layers lying on top of it.