Understanding context switches

A context switch in computer science is the operation or set of tasks by which all the states associated with a running process or thread is saved and the state associated with a different process or thread to be run next is restored so that it can resume where the execution left off. The principle of context switching is the cornerstone on which modern Operating Systems' (OSs') support for multitasking is based, and which gives the illusion of running a lot more processes than the number of CPU cores available in the hardware.

Types of context switches

Context switches can be grouped into different types depending on which aspect of the context switching process we look at. We will briefly discuss them as follows.

Hardware or software context switches

Context switches can be performed in hardware or software. In hardware context switching, special hardware features such as Task State Segments (TSSs) can be used to save the register...