ITPEC FE Morning April 2021 Question 17
ITPEC FE Morning April 2021 — Question 17 of 80
Context Switch in Multiprogramming — three OS steps when switching processes.
When a process is interrupted, the OS performs a context switch in this order:
- •A — Save the running state of the current process (registers, program counter → PCB)
- •B — Select the next process via the scheduler
- •C — Restore the saved state of the selected process from its PCB
Mnemonic: S-S-R — Save, Select, Restore.
Why not others:
- (a) Restore → Select → Save — cannot restore before selecting which process to load
- (b) Save → Restore → Select — cannot restore before selecting
- (d) Select → Restore → Save — must save current state before doing anything else
AI-generated — may contain errors
The original exam layout is preserved in the image so diagrams, formulas, tables, and code remain accurate.
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