Apr 15, 2013

The differences among short-term, medium-term, and long-term scheduling


What are the differences among short-term, medium-term, and long-term scheduling

Answer:

Short-term(CPU scheduler)—selects from jobs in memory those
jobs that are ready to execute and allocates the CPU to them.

Medium-term—used especially with time-sharing systems as an
intermediate scheduling level. A swapping scheme is implemented
to remove partially run programs from memory and reinstate them
later to continue where they left off.

Long-term(job scheduler)—determines which jobs are brought into memory for processing.
The primary difference is in the frequency of their execution. The short-term must select a new process quite often. Long-term is used much less often since it handles placing jobs in the system and may wait a while for a job to finish before it admits another one.


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