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5. Purpose of Scheduling

The scheduling part of the operating system has the following duties

• Process as many jobs as possible
• Make maximum use of CPU time
• Be responsive to the user so they are unaware of a delay to their process
• Make maximum use of resources such as input-output devices
• Be fair to all jobs - none left stranded for too long
• Be able to prioritise jobs
• Be able to alter priorities according to some rules built into the scheduler
• Avoid 'deadlock'

As you can see in the list above, the scheduler has many duties to fulfill. The ideal scheduler would be one that is making 100% use of the CPU, no jobs are left hanging around and the user is never aware of a time delay also no resources are left idle if a process is wanting to use it.