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EXAMhelp · GATE notes
Operating Systems
CH 01Scheduling, deadlock, paging
Key points
- SJF gives the minimum average waiting time (among non-preemptive); SRTF is its preemptive version.
- 4 conditions for deadlock: mutual exclusion, hold & wait, no preemption, circular wait.
- Banker's algorithm is for deadlock avoidance.
- Belady's anomaly occurs in FIFO, not in LRU or Optimal.
- Deadlock-free condition: n processes, each needing max k resources → resources ≥ n(k − 1) + 1.
Formulas & facts
- Turnaround time
- Completion − Arrival
- Waiting time
- Turnaround − Burst
- EMAT (TLB)
- h(t + m) + (1 − h)(t + 2m)
- Page table size
- Entries × entry size