Changelog

Quantum is playable 2026-08-30

Eight schedulers over the same workload, swappable mid-run: FCFS, round robin, SJF, SRTF, priority with aging, MLFQ, a CFS-like weighted fair scheduler, and EDF.
Demand paging with four replacement policies, shifting working sets, and admission control — plus a thrashing scenario where the CPU is idle precisely because nothing is getting done.
Mutexes with a wait-for graph, cycle detection checked against brute force, lock ordering as prevention, and priority inheritance for inversion.
Nine scenarios and a sandbox, from a three-process Gantt chart to dining philosophers and a Mars Pathfinder-style priority inversion.

Raft as specified in the paper, plus a deliberately naive primary-backup mode that produces split brain on purpose.
Nine scenarios: elect a leader, minority partition, split brain, election storm, divergence and truncation, slow disk, three nodes or five, clock skew, and a sandbox.
A history checker with the global view that flags lost writes, stale reads, duplicate application and concurrent leaders — and scores correctness harder than availability.
Thirteen insights, thirty-two glossary terms, and a postmortem whose contributing factors are generated from the run rather than picked from a list.