tehtäväkeskeytysten

Tehtäväkeskeytykset, in Finnish computing terminology, refer to the mechanisms by which a running program (a task or process) is temporarily suspended to allow another task to execute or to handle an event. These interruptions are fundamental to the operation of modern operating systems, enabling multitasking and responsiveness.

There are two primary types of task interruptions. Hardware interrupts are triggered by external hardware devices, such as a keyboard press, mouse movement, or a network packet arriving. When a hardware device needs attention, it sends a signal to the CPU, which then pauses the currently executing task, saves its state, and branches to a specific interrupt service routine to handle the event. Once the routine is complete, the interrupted task can be resumed.

Software interrupts, on the other hand, are initiated by the running program itself. This typically occurs when a program needs to request a service from the operating system kernel, such as reading from a file, writing to the screen, or allocating memory. This is often done through system calls. The program deliberately triggers an interrupt, and the kernel's interrupt service routine handles the request before returning control to the program.

Interrupts are crucial for efficient resource utilization. Without them, a CPU would have to constantly poll devices to check for input, wasting significant processing power. Interrupts allow the CPU to perform other tasks until explicitly notified of an event, leading to a more dynamic and responsive computing environment. The precise handling and management of these interruptions are a core function of the operating system kernel.