Jailbreaking & Rooting

iOS jailbreaking is the process of removing limitations on iOS, Apple's operating system on devices running it through the use of software and hardware exploits; such devices include the iPhone, iPod touch, iPad, and second-generation Apple TV. Jailbreaking permits root access to the iOS file system and manager, allowing the download of additional applications, extensions, and themes that are unavailable through the official Apple App Store.

Restoring a device with iTunes removes the jailbreak.

One of the reasons for jailbreaking is to expand the feature set limited by Apple and its App Store checks apps for compliance with its iOS Developer Program License Agreement before accepting them for distribution in the App Store. However, their reasons for banning apps are not limited to safety and security and may be construed as arbitrary and capricious. To access the list of banned apps, users rely on jailbreaking to circumvent Apple's censorship of content and features. Jailbreaking permits the downloading of programs not approved by Apple, such as customization apps used to change the User Interface.

Since software programs available through Cydia are not required to adhere to App Store guidelines, many of them are not typical self-contained apps but instead are extensions and customizations for iOS and other apps. Users install these programs for purposes including personalization and customization of the interface, adding desired features and fixing annoyances, and making development work on the device easier by providing access to the filesystem and command-line tools.

Many Chinese iOS device owners also jailbreak their phones to install third-party Chinese character input systems because they are easier to use than Apple's.
Rooting (Android OS)

Android rooting is the process of allowing users of smartphones, tablets, and other devices running the Android mobile operating system to attain privileged control (known as "root access") within Android's sub-system.

Rooting is often performed with the goal of overcoming limitations that carriers and hardware manufacturers put on some devices, resulting in the ability to alter or replace system applications and settings, run specialized apps that require administrator-level permissions, or perform other operations that are otherwise inaccessible to a normal Android user. On Android, rooting can also facilitate the complete removal and replacement of the device's operating system, usually with a more recent release of its current operating system.

As Android derives from the Linux kernel, rooting an Android device gives similar access administrative permissions as on Linux or any other Unix-like operating system such as FreeBSD or OS X.

Root access is sometimes compared to jailbreaking devices running the Apple iOS operating system. However, these are different concepts. Jailbreaking describes the bypass of several types of Apple prohibitions for the end user: modifying the operating system (enforced by a "locked bootloader"), installing non-officially approved apps via sideloading, and granting the user elevated administration-level privileges. Only a minority of Android devices lock their bootloaders—and many vendors such as HTC, Sony, Asus and Google explicitly provide the ability to unlock devices, and even replace the operating system entirely. Similarly, the ability to sideload apps is typically permissible on Android devices without root permissions. Thus, it is primarily the third aspect of iOS jailbreaking relating to giving users superuser administrative privileges that most directly correlates to Android rooting.
Description

Rooting lets all user-installed applications run privileged commands typically unavailable to the devices in the stock configuration. Rooting is required for more advanced and potentially dangerous operations including modifying or deleting system files, removing carrier- or manufacturer-installed applications, and low-level access to the hardware itself (rebooting, controlling status lights, or recalibrating touch inputs.) A typical rooting installation also installs the Superuser application, which supervises applications that are granted root or superuser rights. A secondary operation, unlocking the device's bootloader verification, is required to remove or replace the installed operating system.

In contrast to iOS jailbreaking, rooting is not needed to run applications distributed outside of the Google Play Store, sometimes called sideloading. The Android OS supports this feature natively in two ways: through the "Unknown sources" option in the Settings menu and through the Android Debug Bridge. However some carriers, like AT&T, prevent the installation of applications not on the Store in firmware, although several devices (including the Samsung Infuse 4G) are not subject to this rule, and AT&T has since lifted the restriction on several older devices. As of 2012 the Amazon Kindle Fire defaults to the Amazon Appstore instead of Google Play, though like most other Android devices, Kindle Fire allows sideloading of applications from unknown sources, and the "easy installer" application on the Amazon Appstore makes this easy. Other vendors of Android devices may look to other sources in the future. Access to alternate apps may require rooting but rooting is not always necessary.

Rooting an Android phone lets the owner modify or delete the system files, which in turn lets them perform various tweaks and use apps that require root access.