1. Running -> Blocked
2. Running -> Ready
3. Ready -> Running
4. Blocked -> Ready

Events:

• timer interrupt
• Running process makes a system call
• A system call completes (e.g. a resource becomes available)

Scheduler: Handles transition 3. But note that transition 4 goes from Blocked to Ready, not Blocked to Running.

This typically gives more chance of implementing whatever scheduling policy is desired.