LithosAnanake/disk/README.md

disk/

QEMU disk images used for Artemis (block-storage VM) persistence testing. Mounted via Makefile.starkernel's ARTDISK variable (default disk/artemis.img) as a virtio-blk-pci device on all three architectures' kernel QEMU boots — not scripts/rundisk.sh, which targets a separate, currently-unused disks/ (plural) directory for the hosted VM's --disk-img= flag instead.

• artemis.img — standard Artemis persistence test disk. Reformatted 2026-08-02: this image had been stuck in a corrupted state (valid LithosAnanke magic header, but data not matching what ART-READ-TEST expects) since before this repo's own git history begins (git log shows it already broken at the initial commit, carried over from the pre-split monorepo). Chasing down the resulting persistent FAIL: persist-read traced to the data, not the code — the write→reboot→read round trip works correctly on a fresh image (see artemis-debug-roundtrip.img below). Reformatted by blanking the file and letting a normal boot format+write-test it; verified PASS: persist-read on amd64, aarch64, and riscv64 against the same image afterward (cross-arch resume, matching the arch-neutral on-disk format .claude/ARTEMIS.md specifies).
• artemis-debug-roundtrip.img — round-trip regression fixture created during that investigation. Known-good: format → self-test → write-test → reboot → resume → PASS: persist-read, confirmed 3 times in a row. Keep this in a passing state; if a future change breaks it, that's a real regression, not a stale-fixture artifact like artemis.img was.
• artemis-persist-test.img — persistence round-trip test image (pre-existing; history/state not re-verified during the above investigation).
• artemis-poison.img — a separate test image (exact scenario not documented elsewhere in the repo as of this writing; name suggests an adversarial/corruption test, not confirmed).
• artemis-unrecognized-test.img — exercises ART-HALT-UNRECOG (.claude/ARTEMIS.md acceptance criterion #6). Regenerated 2026-08-02: the previous copy of this file had itself been silently reformatted by a since-fixed bug in the generic block subsystem (src/block_subsystem.c) — it carried a valid low-level 'STFR'/v2 header despite being meant to represent foreign disk content, direct forensic evidence of the bug described in .claude/ARTEMIS.md's Build Status item 6. Regenerated as 30MB of a repeating POISON-UNRECOGNIZED-DISK-TEST-FIXTURE--NOT-BLANK-NOT-STFR-NOT-ARTEMIS-- ASCII pattern — deliberately neither blank, nor the block subsystem's own 'STFR' magic, nor Artemis's "ARTEMIS\0" marker. Verified on amd64 and riscv64 post-fix: boot correctly halts (ARTEMIS HALT: unrecognized disk content) and the file's sha256 is now byte-for-byte identical before and after boot. Keep this fixture in this poisoned state — if a future change makes its sha256 change across a boot, that is exactly the regression this fixture exists to catch.

Note on incidental header churn: artemis.img picks up a few changed header bytes on every ordinary boot even though no user data changes — blk_subsys_attach_device() always records a fresh mounted_time on a successfully recognized disk, which gets flushed at shutdown. This is expected bookkeeping, not a bug; revert it before committing rather than carrying timestamp noise in git history.

• usb-thumbdrive-test.img — 64MB raw image backing a QEMU usb-storage device attached to the xHCI controller's bus (xhci0.0) for Milestone 2e/ 2h hotplug testing, added 2026-08-22. Blank (all zero) — blkio_usb.c + blk_subsys_attach_device() wiring (Milestone 2h, done 2026-08-25) attach it as BLK_FMT_PROVISIONAL every time, which is the intended, exercised state; not yet BLK_FMT_FORMATTED via BLK-CONFIRM-FORMAT.

• usb-thumbdrive-test2.img — 64MB raw image, added 2026-08-25 for Milestone 2h hot-detach/re-attach verification. Filled with a repeating HOTDETACH-REATTACH-FIXTURE-2026-08-25-- ASCII pattern, deliberately distinguishable from usb-thumbdrive-test.img's all-zero content — the point is proving a block read after detaching usb-thumbdrive-test.img and re-attaching this one actually returns this pattern rather than silently replaying the old device's cached (all-zero) content, which is exactly the class of bug a same-LBN-range device swap can cause if the VM block window cache (vm->blk_vm_cbuf[]) isn't re-validated on a hit.

• artemis-reloc-test.img — 64MB raw image, added 2026-08-25 for single-block relocation (RELOCATE-BLOCK) persistence verification. Blank at creation; a genuinely fresh volume was required (not artemis.img) because relocation-table capacity (reloc_start/reloc_devblocks in blk_volume_meta_t) is only reserved by blk_compute_fresh_geometry() on a fresh format — artemis.img predates the feature and correctly reads back reloc_devblocks=0 from what was previously unused header padding. Attach via make -f Makefile.starkernel ARTDISK=disk/artemis-reloc-test.img ... (the Makefile's ARTDISK var is ?=-overridable). Not yet BLK-CONFIRM-FORMAT-committed in the repo copy — commit that step live if reusing this fixture for further reloc-table testing.

• zuse.img — 64MB raw image simulating the physical Zuse superuser thumbdrive for QEMU testing (FABRIC-3.md, Phase 8: zuse.img "bleach" mechanism, added 2026-08-26). Blank (all zero) at creation — reads back as HOMEBLOCKS_SIG_BLANK via homeblocks_sig_check(), confirmed live (xhci: USB drive not recognized (blank or foreign media)), simulating a genuine first boot for exercising the still-to-be-built one-time mint-Zuse flow. "Bleach" it back to this pristine/unminted state with scripts/bleach_zuse_img.sh before each first-boot test run, rather than hand-regenerating the file — same all-zero content either way, the script just makes the reset a single documented, repeatable command. Deliberately a flat/raw image, not GPT-partitioned, matching homeblocks_sig_check()'s current call site (repl.c, sig_start_fblock=0) — both will move to a real GPT-partition-relative offset together once a GPT parser exists, not attempted ahead of that.

Convention, standing as of 2026-08-22: every virtual disk/thumb-drive image used for testing — Artemis persistence disks above, and USB Mass Storage backing images alike — lives in this directory and is a tracked, committed file, never scratchpad. This was already artemis.img's convention; usb-thumbdrive-test.img and any future USB test images follow the same rule. Confirmed no .gitignore in this repo excludes disk/*.img.

These are regenerable QEMU raw disk images, not source — see .claude/ARTEMIS.md for the storage model they exercise.