Tehtäväkeskeytykset

Tehtäväkeskeytykset, known in English as task switching or context switching, refer to the process where a computer's central processing unit (CPU) stops executing one task or process and begins executing another. This allows a single CPU to handle multiple tasks concurrently, giving the illusion of parallel execution. The operating system is responsible for managing these task switches.

When a task switch occurs, the operating system must save the current state of the task being interrupted. This state includes information such as the values of CPU registers, the program counter, and other relevant data. This saved state is often referred to as the task's context. Once the context is saved, the operating system can then load the context of the next task to be executed. This loading process restores the CPU to the state it was in when the new task was last paused.

Task switching is fundamental to multitasking operating systems. It enables users to run multiple applications simultaneously, such as browsing the web while listening to music or editing a document. The efficiency of task switching significantly impacts the overall responsiveness and performance of a computer system. Frequent or lengthy task switches can lead to a phenomenon known as "context switching overhead," where the time spent saving and loading contexts detracts from the actual work being done by the tasks. Operating system designers strive to minimize this overhead to ensure a smooth user experience.