Priorities and scheduling

Each process will have a priority set to it by the scheduling algorithim. Depending on the algorithim wikl depend on what priority is given to a process. For example the MFQ will give a higher priority to I/O bound processes rather than process bound.

Processes with a higher priority will normally run before processes with a lower priority. This may not always be the case otherwise low priority processes may never get a chance to run. This is known as starvation.

Priorities come into play when -

• The scheduler is adding a new process to the ready to run queue
• The scheduler decides on where to put a process back into the ready to run queue

As a process runs it may have it's priority changed. For example in SRT will increase the priority as the process runs while MFQ will increase priority if a process becomes blocked.