THE FOLD / CO-OP / THE BROADCAST / THE TOTAL ORDER BROADCAST
THE TOTAL ORDER BROADCAST
a way of making everyone wrong in the same direction
1 WHAT IT IS · WHAT IT DOES · FACT OR FICTION
Causal delivery guarantees you never see an effect before its cause. It says nothing whatever about two messages that have no cause between them — and replicas that disagree on those diverge while every one of them is behaving correctly.
LIT verified live. Two concurrent messages, 5 receivers, every delivery order enumerated: 32 in total. Causal order permits all 32. Only 2 of them have every receiver agreeing — 6.25%. The other 30 are causally legal and leave the replicas in different states, which is exactly the gap total-order broadcast exists to close.
LIT verified live. Two concurrent messages, 5 receivers, every delivery order enumerated: 32 in total. Causal order permits all 32. Only 2 of them have every receiver agreeing — 6.25%. The other 30 are causally legal and leave the replicas in different states, which is exactly the gap total-order broadcast exists to close.
2 HOW IT WAS WEAVED · AI + HUMAN
Total order broadcast is equivalent to consensus — it is not a stronger delivery guarantee bolted on, it is the same problem wearing different clothes.
AVAN (AI) enumerated rather than reasoned, because 2 of 32 is a number and “causal is weaker than total” is a slogan. The ratio is the argument: agreement is not the common case that occasionally fails, it is 6.25% of the space, and everything else is a legal execution that has quietly forked your state.
AVAN (AI) enumerated rather than reasoned, because 2 of 32 is a number and “causal is weaker than total” is a slogan. The ratio is the argument: agreement is not the common case that occasionally fails, it is 6.25% of the space, and everything else is a legal execution that has quietly forked your state.
3 ONE DIMENSION
All thirty-two delivery orders. Two of them agree.
4 TWO DIMENSIONS · INTERACTIVE
Add receivers and watch agreement collapse.
5 THREE DIMENSIONS + AVAN’S INVERSE
The green forward object: one broadcast, many arrivals.
AVAN’s addition (the inverse-companion): the forward reading is that total order broadcast fixes replica divergence. The inverse is that it fixes it by inventing an order that does not exist. The two messages are genuinely concurrent; no fact about the world says which came first, so agreeing on one is not discovering the truth, it is manufacturing a convention and committing to it. Read backwards, consensus is not a way of learning what happened — it is a way of making everyone wrong in the same direction, which turns out to be the only useful thing available.
LIT two concurrent messages across 5 receivers give 32 delivery orders when every one is enumerated, all 32 permitted by causal order, and only 2 of them have every receiver agreeing - 6.25% - leaving 30 that are causally legal and leave the replicas in different states
FIG Total order broadcast is equivalent to consensus - not a stronger delivery guarantee bolted on but the same problem wearing different clothes. AVAN enumerated rather than reasoned, because 2 of 32 is a number and causal is weaker than total is a slogan. The ratio is the argument: agreement is not the common case that occasionally fails, it is 6.25% of the space.
FIG Total order broadcast is equivalent to consensus - not a stronger delivery guarantee bolted on but the same problem wearing different clothes. AVAN enumerated rather than reasoned, because 2 of 32 is a number and causal is weaker than total is a slogan. The ratio is the argument: agreement is not the common case that occasionally fails, it is 6.25% of the space.
◆ sealed .dlw.fold → folded to ROOT_0 · a sphere of THE BROADCAST · David Lee Wise (ROOT0), with AVAN