Corrected substrate: this OS is anti-POSIX, anti-file by design -- the prior "dedicated system-identity disk" framing was wrong vocabulary, caught before any code was written (saved as feedback_no_files_anti_posix.md). The real primitives are content-addressed capsules and raw LBN blocks, never a filesystem. Design (agreed on request): a growable metadata fence at the TOP of a device's block space, mirroring block_subsystem.c's existing bottom BAM reservation from the opposite end -- the two grow toward each other, never colliding, same shape as a stack/heap. Starts at BLK_META_FENCE_INIT (128 blocks), explicitly never RAM-backed. Reuses Artemis's already-attached, already-proven virtio-blk device -- no new device. Rejected reusing BAM's own reserved zone directly: those blocks are fully claimed by BAM bookkeeping, not free space. Step 1 only: new meta_fence_blocks field in blk_volume_meta_t, appended after reloc_devblocks and carved from _pad[] -- identical graceful- default technique reloc_devblocks already established (a pre-existing volume reads it back as 0, not a format break). Added a compile-time _Static_assert on the struct's total size, same discipline homeblocks_sig.h uses -- caught a real bug immediately: the hand-summed _pad[] formula was off by 4 bytes (a compiler alignment gap the manual count missed), found via offsetof() rather than re-deriving by hand. Worked against disposable clones throughout, never the real disk/artemis.img (ARTDISK is ?=-overridable) -- artemis-metafence-fresh.img (blank, fresh-format path) and artemis-metafence-test.img (copy of the pre-existing artemis.img, graceful-default-on-reload path), kept as regression fixtures matching disk/README.md's existing convention. Verified independently via direct byte reads of the disk image, not the kernel's own log output (log_message(LOG_INFO,...) doesn't reach serial in this build -- unrelated pre-existing gap): fresh format writes 128 at header offset 184, a reboot without reformatting preserves it, the old pre-fence image reads back 0. Full 3-arch acceptance boot against the real, untouched disk/artemis.img also clean. Allocator (user_blocks math) and zone read/write accessors both still open -- next steps, documented in FABRIC-3.md. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01U14ET9CWAtbQMbYqomKgXd
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 |
init-0.4th … init-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