Rooting is a process that allows users of mobile phones and other devices running the Android operating system to attain privileged control (known as “root access“) within Android’s Linux subsystem with the goal of overcoming limitations that carriers and manufacturers put on some devices. It is analogous to jailbreaking on devices running the Apple iOS operating system.
Most retail devices running the Android operating system must be rooted in order to install custom versions of the Android system such as CyanogenMod. This is because in the stock configuration (unrooted), user-installed applications do not have direct access to the flash memory chip on the device and, thus, are not able to replace or modify the operating system itself. Rooting is also necessary for certain applications and widgets that require additional system and hardware rights such as for rebooting the phone, certain backup utilities, and other access to other hardware such as status LEDs. Rooting is also needed to disable or remove manufacturer-installed applications such as City ID. Rooting the phone typically also includes installing an application called Superuser that supervises which applications are granted root rights.
In contrast to iOS jailbreaking, rooting is not needed to run applications not distributed by the official Android Market (sometimes referred to as “side-loading“). However some carriers, like AT&T, prevent the installation of applications not on the Android Market in firmware.
On July 26, 2010, the U.S. Copyright office announced a new exemption making it officially legalto root a device and run unauthorized third-party applications, as well as the ability to unlock any cell phone for use on multiple carriers.
iOS jailbreaking, or simply jailbreaking, is the process of removing the limitations imposed by Apple on devices running the iOS operating system through use of custom kernels. Such devices include the iPhone, iPod Touch, iPad, and Apple TV 2G. Jailbreaking allows users to gain full access (or root access) to the operating system, allowing iOS users to download additional applications, extensions, and themes that are unavailable through the official Apple App Store, via installers such as Cydia. A jailbroken iPhone, iPod Touch, or iPad running iOS can still use the App Store, iTunes, and other normal functions, such as making telephone calls. Unlike rooting an Android device, jailbreaking is necessary if the user intends to run software not authorized by Apple.
At its core, jailbreaking an Apple iOS device gives access to its root filesystem, allowing modification and installing third-party software components. This gives the user more control over the device and may enable features that were previously unavailable. In many cases, jailbreaking also voids the device’s warranty.
Under the DMCA of 2010, jailbreaking Apple iDevices is legal in the United States, although Apple has announced that the practice “can void the warranty.”However, the jailbreaking process does not include any modification to the hardware, so it can be quickly and easily reversed simply by restoring the operating system through iTunes.