Jailbreaking simply means getting the root access of your Apple iPhone, Jailbreaking your iPhone will remove the Default Apple made kernel( Kernel is the Heart of the OS in this case iOS ) and install a custom kernel, which is used to grant root access to your device. Fix iPhone Overheating Issues Jailbroken devices have the ability to install App’s that aren’t in the app store due to some reason. With root access to kernel you can do many customizations to your device which Apple don’t provide in their Default kernal.
Defination according to wikipedia of jailbreaking is as follows:
“iOS jailbreaking is the removing of software restrictions imposed by iOS, Apple’s operating system, on devices running it through the use of software exploits; devices include the iPhone, iPod touch, iPad, and the AppleTV 2 and 4. 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.” source wikipedia.
Jailbreaking of iPhone is started from the launch of the first Generation of iPhone and it is present till date every time the new iOS is released Jailbreaking communities find some way to jailbreak the version of the iOS and it is continues process will not stop communities will keep on updating and improving.
Types of Jailbreaks
there are mainly 2 types of Jailbreak
“untethered” jailbreak it simply means that the once you have jailbroken your device you don’t need computer to access the patched kernel.You can say untethered jailbreak as permanent jailbreak.
Tethered Jailbreak is opposite of untethered jailbreak you need to attach the device to computer every time your reboot your device to access patched kernel. Themacinsider Tethered jailbreak is also called temporary jailbreak.
Legal or illegal :
Many countries don’t have such laws, but some countries like USA has legalized jailbreaking but iPhone and iPod touch not iPad you can jailbreak iPhone and iPod touch but it is illegal to jailbreak iPad.