Implements FABRIC-3.md §XXXII.2's scratch-thumbdrive mint mechanism: capsule_mint_identity_scratch() (capsule_mint.c/.h) builds a throwaway RAM-backed blkio_dev via blkio_ram.c's backend and runs capsule_mint_identity() against it completely unmodified -- same live Zuse-signing operation, same rng_get_bytes() draw for drive_uuid a real thumbdrive gets. Reads back only drive_uuid + the cert devblock; the seed devblock is written into the scratch buffer internally but never read out (no seed is ever baked into a capsule, per the ratified no-seed decision). New FORTH word MINT-SCRATCH (mama_forth_words.c), same stack signature as MINT, mints into the scratch device instead of any attached drive and never touches sk_repl_get_attached_blk_dev() or console-pairing state. Prints the drive_uuid as hex so a live boot log itself proves each call drew fresh entropy. Build correction found along the way: blkio_ram.c was excluded from the kernel build (Makefile.starkernel VM_EXCLUDE) alongside blkio_factory.c/blkio_file.c. blkio_factory_open() unconditionally references blkio_file.c's real fopen()/fread() file I/O, which has no freestanding-kernel equivalent, so the factory function couldn't be used as-is. blkio_ram.c itself is pure memcpy over a caller buffer -- pulled it alone into the kernel build and wired it directly in capsule_mint.c, the same way blkio_factory.c's own extern declarations do internally. Verified live on amd64: two MINT-SCRATCH calls produced two genuinely different drive_uuids (b533246d.../ae11b2b2...), confirming fresh entropy per call rather than stale reuse; VM stayed healthy afterward (5 6 + . -> 11). Clean 3-arch qemu boot (amd64/aarch64/riscv64), logs and DoE CSVs committed per standing convention. Remaining punch-list items (hand-transcription into a .4th block, the unattended-birth call site, the ACL cap bit) not started. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01BWpNjdwPtFLuVLaAq44L9K
capsules/
FORTH personality files loaded by the VM at boot. A capsule is an immutable, content-addressed payload; its XXHash64 hash is its identity. Any mutation changes the hash and the birth protocol rejects the image.
Key files
| File | Type | Purpose |
|---|---|---|
init.4th |
(m) MAMA_INIT |
Default Mama VM personality — loaded at LBN 2048 |
ACL.4th |
user | Word-level ACL system; self-activating at boot |
zuse.4th |
user | Bootstrap superuser; loaded by ACL.4th |
doe.4th |
user | DoE workload words (EXEC-DOE) — opt-in |
workload-0.4th … workload-9.4th |
(p) |
Numbered personality variants |
init-l8-*.4th |
(p) |
L8 Jacquard mode variants (stable/volatile/diverse/temporal/transition/omni) |
hermes/init.4th |
(p) |
Hermes baby VM personality |
artemis/init.4th |
(p) |
Artemis baby VM personality |
Block namespace
Block ranges are shared across all loaded capsules — collisions cause silent word-definition overwrites.
| Range | Owner |
|---|---|
| 2048–2099 | init.4th |
| 2100–2199 | doe.4th |
| 3000–3999 | workload capsules |
| 4000+ | user-defined (ACL.4th, zuse.4th, …) |
Each block is limited to 1024 bytes. Verify with wc -c before committing.
See also
experiments/bare_metal/README.md— DoE protocols and block namespace rulesdocs/03-architecture/word-acl/DESIGN.md— ACL system designtools/mkcapsule.c— assembles capsules intocapsule_generated.c- Project root