Schedulers

• Short-term scheduler is invoked very frequently (milliseconds) Þ (must be fast).
• Long-term scheduler is invoked very infrequently (seconds, minutes) Þ (may be slow).
• The long-term scheduler controls the degree of multiprogramming.
• Processes can be described as either:

1. I/O-bound process – spends more time doing I/O than computations, many short CPU bursts.
2. CPU-bound process – spends more time doing computations; few very long CPU bursts.