v86's async loaders leave the ATAPI drive in BSY across an event-loop
turn after a READ(10) CDB. Win95's ESDI_506 reads status twice, sees
BSY both times, and issues DEVICE RESET ~165 instructions later, which
cancels the in-flight read — the drive enumerates but D: never mounts.
Serve the ISO through a small fs.readSync-backed buffer so the data is
available before the next emulated instruction runs, and re-enable the
CD-ROM settings tab.
Also: WIN95_PROBE_CDROM / WIN95_PROBE_CDTRACE harness hooks, and pump
one screen-adapter frame before screenshotting so probe captures work
when the Electron window is occluded.
Rebuilds libv86.js from felixrieseberg/v86@windows95-base, which now
carries vga-defer-vbe-disable-v86: when a windowed DOS VM's vgabios
writes dispi[4]=0, Win9x's VDD passes that through (it doesn't know
about ports 1CE/1CF) while virtualising the rest of the mode-set, so
v86 used to drop out of LFB rendering with the legacy registers still
holding SVGA values and the screen turned to planar garbage. The fix
defers the disable until a legacy attribute-mode write actually
reaches the hardware.
debug-harness: WIN95_PROBE_DOSBOX=1 opens command from Run, types
dir, optionally Alt+Enters (WIN95_PROBE_DOSBOX_ALTENTER=1).
WIN95_PROBE_VGATRACE=1 wraps the VGA io.ports[] entries (not the
VGAScreen methods, which are captured by-value at registration) and
dumps [port, op, value, eip+VM/PE/CPL] tuples to
/tmp/win95-vgatrace.json — that EIP/mode column is what pinned the
leak on V86-mode vgabios at C000:2C8x.
* Rewrite update-v86.js for the current build pipeline
Both v86 fixes we've been carrying are now real branches on the fork
(PR #1540 electron-renderer-fs-loader, PR #1541 ide-shared-registers)
combined as felixrieseberg/v86:windows95-base. update-v86.js no longer
needs to patch sources at build time — it just builds whatever's checked
out and copies the result.
Gone: the fallback-to-copy.sh path, the skew-day check, the structural
regex patches for load_file/exportSymbol/fetch-bind, the phantom-slave
guard (both are in the branch), the --js-only flag. If you don't have
cargo/clang/java/closure, the script fails loudly — no silent fallbacks.
Added: sanity checks against the installed libv86.js for the invariants
our SMB integration and parcel-build shim depend on, so if upstream
changes something load-bearing we see it as a WARN at update time
instead of a runtime failure.
Tested end-to-end: 5/5 sanity checks, fresh boot SUCCESS in 32s.
* docs and skills: capture SMB/v86/testing knowledge from the session
- docs/smb-share.md: user-facing SMB integration overview (how to mount in
Win95, what's implemented, what's not). Points at the protocol-level
README inside src/renderer/smb/ for wire-level gotchas.
- .claude/skills/probe-win95: how to boot and test the VM without a human.
Env vars, file locations, failure modes, the XT scancode keyboard trick,
bisect rules of thumb.
- .claude/skills/update-v86: how to pull upstream v86 changes, what the
five sanity-check WARNs mean, how to retire the fork branches when the
PRs merge upstream.
.gitignore narrowed to exclude only the runtime dirs (scheduled_tasks.lock,
worktrees) instead of the whole .claude/ tree, so skills can be committed.
