The Principia Machina/Diagrams/09 Lock and petition queue

Structural diagram 9 of 12. Part of the TPM hub.

• KIND: process
• LANGUAGE: Mermaid sequence
• GENERATED FROM: per-container lock page state; TPS 5.7, 5.8.5
• STATUS: hand-authored at TPS 0.1.0; superseded by TPX at its first build
• SOURCE SHA-256: e67a07601554beb77e1b559b098b92209b389956016ddf19145d5fe44e1b710f

Rendered live from the source below, which is the text equivalent; if rendering is unavailable the source still stands.

Text equivalent

The lead acquires the lock by a base-revision edit writing holder, grant, grant time and expiry (5.7.2), extends it by heartbeat never past 24 hours (5.7.3), pushes with the grant number under the fencing check with the badge written last (5.9.8, 5.10.1), and releases only after that push (5.7.5). The queue head acquires within the ACQUISITION WINDOW, else the next waiter may (5.7.4, 5.8.5); the save hook refuses any out-of-order or pre-expiry acquisition (5.7.1).