# Context Switching in Operating Systems Context Switching is a core process in modern, multitasking operating systems. It allows a single CPU to manage multiple processes or threads by temporarily storing and restoring the computational state of a process. A context of a process or thread is essentially its state, represented by the values in registers, program counter, and stack pointer at a particular point in time. When an interrupt occurs, or when an operating system's scheduler decides to switch control from one running process to another, a context switch must happen. Here's a simplified example of what a context switch might look like in pseudo code: ```code function context_switch(from, to) { save_state(from); load_state(to); } ``` During `save_state(from)`, the operating system saves the context of the currently executing process 'from' into its Process Control Block (PCB). The PCB is a data structure that the OS maintains for each process to store its state and other administrative information. ```code function save_state(process) { process.PCB.program_counter = CPU.program_counter; process.PCB.stack_pointer = CPU.stack_pointer; process.PCB.registers = CPU.registers; } ``` Subsequently, `load_state(to)` loads the context of the next process 'to' from its PCB into the CPU. ```code function load_state(process) { CPU.program_counter = process.PCB.program_counter; CPU.stack_pointer = process.PCB.stack_pointer; CPU.registers = process.PCB.registers; } ``` The context switch process is inherent to the design of multitasking operating systems and its efficient execution is crucial for system performance.