About the cover
The cover shows the Chief Mechanic of the Ferrous Works in a workshop of gears. The crates are labelled
Arc, Mutex, epoll, and Box, and the chain ends in a crate marked unsafe. Each chapter opens
with a member of the same crew at a machine that represents the chapter’s subject.
| Chapter | Mechanic | Machine |
|---|---|---|
| 1 | Rivet | a gate marked TRY_FROM that rejects parts of the wrong shape |
| 2 | Ledger | a filing cabinet, a stack of pages, and an offset counter |
| 3 | Bins | numbered bins fed by a hashing hopper |
| 4 | Shackle | a chain on a crane, one link opened with take() |
| 5 | Conveyor | three belts feeding a heap and one output belt |
| 6 | Branch | a manifold of pipes laid out as a binary tree |
| 7 | Valve | pipes and valves wired into a weighted graph |
| 8 | Cog | a train of gears, each half the size of the last |
| 9 | Drawer | a rack of crates, the oldest leaving by an eviction chute |
| 10 | Turntable | a ring of shards around a hub gear |
| 11 | Gauge | a board of page frames and a cache-miss gauge |
| 12 | Spindle | thread spools on one axle, and a padlock |
| 13 | Carousel | a conveyor queue and a ring-buffer carousel |
| 14 | Foreman | a job hopper feeding four worker robots |
| 15 | Throttle | a token bucket under a refill valve |
| 16 | Signal | a radio mast and a socket panel |
| 17 | Courier | a pneumatic tube delivering a request to status-code slots |
| 18 | Flywheel | a flywheel driven by poll, with futures on a rail |
| 19 | Drill | a drill press and a checklist |
The plates are generated by tools/art.py.