Computer multitasking

Computer multitasking is an operating system’s management of multiple tasks that make progress during the same period, by switching among them or running them concurrently.

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Process scheduling: Process scheduling selects which ready process or thread receives processor time and when. Schedulers allocate processor time among runnable tasks, shaping their progress and responsiveness.
Process (computing): A process is a running program with its own execution state, resources, and protected address space. Operating systems commonly schedule processes as independent units of work.
Interactive computing: Interactive computing lets people exchange input and output with a computer while programs are running. Responsive interaction depends on scheduling work without making active programs feel stalled.
Cooperative multitasking: Cooperative multitasking lets a running task keep the processor until it voluntarily yields control. It contrasts with preemptive systems, where the operating system can interrupt a task.
Context switch: A context switch saves one task’s execution state and restores another’s so a processor can change tasks. Switches let a processor alternate tasks while preserving each task’s state.
Thread (computing): A thread is an execution sequence within a process that shares the process’s memory and resources. Threads let one program perform several activities under the operating system’s scheduler.
Real-time operating system: A real-time operating system schedules tasks to meet timing constraints with predictable behavior. Real-time multitasking prioritizes deadlines rather than merely sharing processor time fairly.
Preemptive multitasking: Preemptive multitasking allows an operating system to interrupt a task and schedule another. This is the common form of multitasking on general-purpose operating systems.
Time-sharing: Time-sharing divides processor time into intervals so multiple programs can use a computer interactively. Short time slices create the familiar appearance that many programs run at once.
Central processing unit: A central processing unit executes instructions and coordinates operations in a computer. The number of available processor cores limits how much work runs simultaneously.