The Android operating system, used on smartphones and tablets, uses multiple user access levels to control the files and settings that you have access to. If you are the user with the highest access level, root, you're often locked by wireless service providers so you cannot make unauthorized changes to the OS. Rooting tools unlock this user level. You can completely change your Android OS configuration and add in market applications that require root permissions to run on your device.
Most Android phones can be rooted using a manual method that takes advantage of the Android Software Development Kit. The Android Debug Bridge is contained within the kit and is capable of pushing the necessary commands to an Android device to change the user's access level. Android Debug Bridge commands are sent from a computer through a terminal window in order to access parts of the Android operating system, such as the system files. You use other files in conjunction with the Android SDK to complete the manual rooting process.
Some rooting applications are installed directly to your Android based device. These applications are available through Market, the developer's website or development forums such as XDA-Developers.com. These rooting applications may support a specific type of Android phone due to hardware and firmware issues, or support many different Android based devices. When you run the application, the root access is applied to your phone. You may also need to install a custom recovery or bootloader to finish the rooting process.
One Click Rooting
Stand-alone one-click rooting software installs on your computer instead of your phone. You connect the Android device to your computer and execute the root program. Each rooting program has its own way of handling the root process. Like the root applications, computer-based rooting software may be designed for a specific device model or used for a variety of devices.
The rooting process changes the Android device's operating system in ways unsupported by the device manufacturer or service provider. This action voids the warranty and may cause problems if you need to receive support on a device issue. You also have a chance of messing up the root process due to a power loss on the Android device. If you lose power, you may encounter data corruption -- this necessitates restoring the phone to its original factory settings.