The Stage Manager
Five cases in coordination. Two mechanisms, and only two.
A puppet is a character in a program: a named who, defined by his verbs and his journal — the diary of everything he has done, written as sentences, in order. That pair is his identity, not the machine he runs on. These five cases follow what happens when such a character has to stand in more than one place, or speak to another one.
Two mechanisms, and only two.
Nothing in these five cases is a third thing. Where something looks like one, it is one of these two composed with the other.
One character with a body on several machines. One body writes, the others apply what it wrote. What travels is the journal, not the state.
Two characters speaking. The sender asserts what happened in his own history; the receiver decides what to do about it, in his own verbs.
Five situations, one at a time.
- 01The bookkeeperOne character standing on three machines.Replication here is not copying state. It is sharing history.
- 02The heraldThree isolated characters and one shared messenger.The act of speaking became a sentence in the speaker's own program.
- 03Who was told?Reading the answer instead of tracking it.The audit trail was not built. It was written, one sentence at a time, as it happened.
- 04The clerkThe price list is a character, not a tier.The clerk is a source of knowledge, not a source of historical truth.
- 05Topology is a drawingWhere the characters live, and why the script does not care.Identity is the verbs and the history. Never the hardware.
What this does not do.
A claim without a boundary is not worth much, so these are stated here rather than kept for the questions afterwards.
Every edge is a programmatic record in the journal of whoever originated it, but no single journal holds a multi-hop chain. Reconstructing one end to end means composing journals, linked by envelope identifier. Paper 4, §8.5.
A crash between journaling a send and dispatching it strands the envelope. On recovery the transport testifies its fate and the sender records the verdict in its own voice — and a transport that cannot testify leaves the tell pending rather than giving it a fabricated one. Paper 4, §8.5 G4.
A replica can sit behind the Director, and two machines can freeze different values for the same logical instant.
This dissolves the catalogue shape of coordination — configuration, membership, price lists. It does not dissolve coordination tied to liveness: ephemeral locks, leases that expire with a session, ownership that depends on a heartbeat.