Recap of Schedulers

Long-term Scheduler

• Function: Decides the degree of multiprogramming
• Action: Brings jobs from New State to Ready State
• Decision: Whether to bring a process into RAM or not

Short-term Scheduler

• Function: Decides which process to pick from the ready state
• Action: Assigns processor to selected processes
• Importance: Most critical part of scheduling algorithms

Medium-term Scheduler

• Function: Swapping processes between RAM and hard disk
• Actions: Swapping out (RAM to disk) and swapping in (disk to RAM)

Key Point: All scheduling algorithms studied in operating systems courses are designed for the short-term scheduler and focus on processes in the ready state.

Operating System Queues

Ready Queue

• Contains multiple processes in the ready state
• Most important queue from scheduling perspective
• Focus of all scheduling algorithms

Job Queue

• Queue of jobs wanting to be created as processes