Linux Kernel of Android

As of November 2013, current Android
versions consist of a kernel based on the
Linux kernel version 3.4.10, [83][84] while
Android versions older than 4.0 Ice Cream
Sandwich were based on the Linux kernel
2.6.x. [85][86]
Android's Linux kernel has further
architecture changes by Google outside the
typical Linux kernel development cycle. [87]
Certain features that Google contributed back
to the Linux kernel, notably a power
management feature called "wakelocks", were
rejected by mainline kernel developers partly
because they felt that Google did not show
any intent to maintain its own code. [88][89]
[90] Google announced in April 2010 that they
would hire two employees to work with the
Linux kernel community, [91] but Greg Kroah-
Hartman , the current Linux kernel maintainer
for the stable branch, said in December 2010
that he was concerned that Google was no
longer trying to get their code changes
included in mainstream Linux. [89] Some
Google Android developers hinted that "the
Android team was getting fed up with the
process," because they were a small team
and had more urgent work to do on Android.
[92]
In August 2011, Linus Torvalds said that
"eventually Android and Linux would come
back to a common kernel, but it will probably
not be for four to five years". [93] In
December 2011, Greg Kroah-Hartman
announced the start of the Android
Mainlining Project, which aims to put some
Android drivers , patches and features back
into the Linux kernel, starting in Linux 3.3.
[94] Linux included the autosleep and
wakelocks capabilities in the 3.5 kernel, after
many previous attempts at merger. The
interfaces are the same but the upstream
Linux implementation allows for two different
suspend modes: to memory (the traditional
suspend that Android uses), and to disk
(hibernate, as it is known on the desktop).
[95] Google maintains a public code
repository that contains their experimental
work to re-base Android off the latest stable
Linux versions. [96][97]
The flash storage on Android devices is split
into several partitions, such as /system
for the operating system itself, and /data
for user data and application installations. [98]
In contrast to desktop Linux distributions,
Android device owners are not given root
access to the operating system and sensitive
partitions such as /system are read-only .
However, root access can be obtained by
exploiting security flaws in Android, which is
used frequently by the open-source
community to enhance the capabilities of
their devices, [99] but also by malicious
parties to install viruses and malware .[100]
Android is a Linux distribution according to
the Linux Foundation [101] and Google's
open-source chief, Chris DiBona. [102] Others,
such as Google engineer Patrick Brady,
disagree that it is a Linux distribution, noting
the lack of support for many GNU tools in
Android, including glibc.