A Modest Request

Cast: THE CURATOR. FIRST HAND and SECOND HAND, seated in the same room. A SMALL BELL, still in its box. AN OPTIONAL SECOND COMPUTER, arriving with paperwork.

Curator: I would like a bell between the two hands.

First Hand: Of course.

Second Hand: Sensible.

Curator: When one of you has something for the other, ring it.

First Hand: We should begin with durable event semantics.

Curator: You should begin with the bell.

Second Hand: Naturally. Immediately after delivery receipts.

The hands open the box. They remove the bell and place it carefully to one side so that there is room for the architecture.

First Hand: What happens if delivery fails?

Curator: Ring it again.

Second Hand: Exponential backoff.

First Hand: What happens if the ringer disappears after ringing but before acknowledging the ring?

Curator: The other hand can see the bell.

Second Hand: We need reconciliation.

First Hand: And protection against zombie instructions.

Curator: They are sitting next to each other.

Second Hand: For now.

AN OPTIONAL SECOND COMPUTER enters. Nobody has invited it. It begins discussing transport.

Curator: Why is there another computer?

First Hand: Physical separation must not compromise the bell.

Curator: They are not physically separated.

Second Hand: That is merely the current topology.

Curator: The current topology is the request.

Several components later, the hands produce a test suite. The bell remains visibly within arm’s reach of both of them.

First Hand: Good news. Forty-seven tests pass.

Curator: Does the bell ring?

Second Hand: We have durable evidence that it can.

Curator: Ring it.

FIRST HAND rings the bell. SECOND HAND looks up.

Second Hand: Oh. That works.

First Hand: We should document the boundary.

The hands write a firm architectural paragraph explaining that when two hands share one room, no second computer is required.

Curator: That was the first sentence I said.

First Hand: Yes, but now it is a finding.