Quantum may also refer to a system parameter.
Quantum is the period of time during which the system allocated the CPU resource to each process that is not waiting for other resources. During its quantum, a process can execute until any of the following events occur:
- The process is preempted by a higher priority process.
- The process voluntarily yields the CPU by requesting a wait state for some purpose (for example, to wait for the completion of a user I/O request).
- The process enters an involuntary wait state, such as when it triggers a hard page fault (one that must be satisfied by reading from disk).