Watch computers decide
Trace shows, one step at a time, how a computer chooses what to do next, and says why at every step. It runs in your browser. Free, no signup.
CPU
P1
P2
P3
P1
P4
P2
P1
P4
P1
P1
P1
P1
P2
P2
P2
P3
P3
P4
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P4
Operating systems
How an operating system shares one CPU between many processes. Enter your own processes, press play, and read the reason for every decision.
- CPU scheduling simulatorAll five algorithms in one place, and how to choose between them
- First Come First ServedRuns processes in the order they arrive
- Shortest Job FirstPicks the shortest waiting job when the CPU frees up
- Shortest Remaining Time FirstInterrupts for any job that would finish sooner
- Priority schedulingRuns the most important ready process, with or without interrupting
- Round RobinGives each process a fixed slice in turn
- Compare scheduling algorithmsAll five on the same processes, side by side