LithosAnanake/experiments/std79-doe/README.md

std79 DoE — 3(architecture) × 9(identity) × 3(replicate) randomized full-factorial

The formal successor to experiments/std79-exerciser/'s ad hoc campaign (see FABRIC-3.md §XII), requested as a genuine randomized full-factorial design matching this project's own DoE methodology (capsules/doe.4th's Fisher-Yates run-matrix shuffle) rather than convenience batching — and written entirely in FORTH, not host-orchestrated shell scripting. See FABRIC-3.md §XV for the design writeup, §XVI for the real aarch64 Stadium/COOL scaling bug that was found, root-caused, and fixed (src/starkernel/vm/stadium.c), and §XVII for a second, related Stadium bug (stadium_grant_quota()'s donor-floor) found while writing up §XVI and fixed in a follow-up pass — the 3-boot batching workaround below is now historical only; a single boot with all 9 identities simultaneously live works cleanly on all three architectures as of both fixes.

std79-doe.fth is not a capsule loaded via EXEC — feed it as raw text to a running REPL (e.g. socat - UNIX-CONNECT:<serial_sock> < std79-doe.fth), same as the original exerciser, then invoke EXEC-STD79-DOE ( seed lo hi -- ) once loaded. lo/hi select which identity-index range (0-8) this boot's live VMs cover — pass 0 8 for a single boot with all 9 identities simultaneously attached (now confirmed working on all three architectures, see §XVI); a narrower range (e.g. 0 2, 3 5, 6 8) still works too, for running the DoE across multiple smaller boots if ever needed for an unrelated reason. Every boot must use the same seed so INIT-MATRIX/SHUFFLE-MATRIX reproduce the identical 27-slot master permutation; only the lo/hi filter differs, so run_id (always the slot's true position in the master shuffle, 0-26) stays directly comparable across boots.

results-20260911/ holds the raw captured serial output from the original campaign (pre-fix): amd64-doe-raw.log (all 27 trials, one boot, all 9 identities simultaneously live) and {aarch64,riscv64}-doe-batch{1,2,3}-raw.log (27 trials each, split across 3 boots of 3 identities, the then-necessary workaround). Result: 81/81 trials correct, 0 mismatches.

results-20260911-stadium-fix/ holds the rerun after §XVI's O(ncells)-scan fix — one boot per architecture, all 9 identities simultaneously live in every boot, same seed throughout. Result: 81/81 trials correct, 0 mismatches, byte-identical output to the original campaign — and the DOE-RUN header sequence (run_id/id_idx/id_label/rep assignment) is md5-identical across all three raw logs, confirming the master shuffle is genuinely architecture-independent. Total per-architecture wall-clock (boot + all 9 identity attaches + full 27-trial run, one continuous QEMU session): amd64 ~165s, aarch64 ~290s, riscv64 ~161s — aarch64's identity 04 attach alone, which stalled 90+ minutes before the fix, now completes in ~34s.

results-20260911-donor-floor-fix/ holds a further rerun after §XVII's donor-floor fix (same discipline: any Stadium defect repair reruns the whole DoE from the top). Result: 81/81 trials correct, 0 mismatches, DOE-RUN header sequence md5-identical to every prior run. Total wall-clock: amd64 ~161s, aarch64 ~280s (confirms no regression from §XVI's fix), riscv64 ~162s.

results-20260912-reconfirm/ holds a plain reconfirmation rerun the following day, no code changes since §XVII's fix (e51a8d2) — same seed, same single-boot-per-architecture, all 9 identities simultaneously live. Result: 81/81 trials correct, 0 mismatches, shuffle sequence still md5-identical to every prior run. Total wall-clock: amd64 ~151s, aarch64 ~276s, riscv64 ~165s.