Notes / University Notes / Operating System / Chapter 5: Process Scheduling

Chapter 5: Process Scheduling

Created: 2025-12-16Updated: 2025-12-16

Deciding which ready process gets the CPU next: what preemption buys and costs, and how the classic algorithms trade fairness against throughput.

Basic Concepts

Multiprogramming
- multiple processes in memory simultaneously
- one waits for IO, another uses the CPU -> ↑ CPU utilization, ↑ system throughput
CPU-I/O Burst Cycle
- the life of a process isn't continuous computation, but alternates between:
- CPU bursts: short periods of CPU activity
- IO bursts: longer periods of waiting for IO operations
Process Type:
- CPU-bound processes: very few, very long CPU bursts
- IO-bound processes: many very short CPU bursts
Histogram of CPU-Burst Times: the majority of CPU bursts are very short, only a few long ones