Operating Systems

Process Scheduler

Definition

In computing, a process scheduler is the part of the operating system that decides which process runs at a certain point in time. It usually has the ability to pause a running process, move it to the back of the running queue and start a new process.

Why It Matters

The scheduler is responsible for sharing the CPU's time among all the running applications and system processes. A good scheduler ensures that the system feels responsive and that all tasks make progress.

Contextual Example

Even on a single-core CPU, you can run a web browser, a text editor, and a music player at the same time. The process scheduler rapidly switches between these processes, giving each a small slice of CPU time, creating the illusion that they are all running simultaneously.

Common Misunderstandings

  • Scheduling algorithms can be complex, aiming to balance goals like minimizing wait time, maximizing throughput, and ensuring fairness.
  • Different operating systems use different scheduling strategies (e.g., for interactive desktop use vs. high-throughput server use).

Related Terms

Last Updated: December 17, 2025