---
name: sibo-workabout-mx-scanner
description: State of the Psion Workabout MX reverse-engineering / barcode-inventory project and how to resume it
metadata:
  node_type: memory
  type: project
  originSessionId: 74de014e-9cf4-47f6-92f4-c34197ac1858
---

Long-running project (July 2026) reverse-engineering the **Psion Workabout MX** (SIBO OS, NEC V30MX, TopSpeed C) to build a barcode **inventory demo** (scan UPC → DBF database file; add stock, consume by a quantity unit) and, alongside, **complete device programming documentation**. Repo: Gitea **lyrathorpe/sibo-playground**, working branch **`feat/inventory-phase1-scan`** (unmerged). Gitea needs hand-off / the contents API for pushes — see [[git-network-ops]]; [[git-conventions]] for branch/PR rules.

**Committed on the branch (durable, survive reboot):**

- `docs/reference/00-08` + index — the SIBO/MX programming reference (building apps, system/OS, I/O devices, PLIB core, file system & DBF, UI, hardware, and RE'd boot/OS-call internals).
- `code/inventory/` — app scaffold: `upc.c/.h` (UPC-A check-digit validation, correct), `bcode.c/.h`, `scan.c` (Phase-1 diagnostics), `README.md`, **`SCANNER-API.md`** (all scanner findings), **`CONTINUATION.md`** (the on-device debugging procedure to finish).
- `docs/mx-re/toolchain-and-plan.md` — the RE toolchain.
- The **ROM `w2mx_v7.20f_eng.bin`** and the full **SDK + HDK** (manuals as `docs/*.txt`; headers/libs/`bar*.ldd` under `code/SIBOSDK/`; HDK under `code/HDK/`) are on the branch. `/tmp/claude/sibo/` working files (ROM slices, MAME rom dir, Ghidra/decomp output) are transient and reproducible from the toolchain doc.

**Scanner — key result:** the integral laser is driven as an **OO library object** in `SCANNER.DYL` (category token **`oscanner`**) via `p_getlibh` → `p_newsend`/`f_newsend` → `p_send`, over **LIBMANAGER (INT 0x84)** / **MESSMANAGER (INT 0x83)** — NOT raw device I/O. Confirmed on the physical device: `p_open("WL2:D")` + control ops **6** then **7** (`p_iow(chan,6); p_iow(chan,7)`) fire the laser to a good decode (green LED). Default Symbol2 11-byte param block: `04 3f 01 15 06 04 1e 80 0d 0a 06` (decoded output is CR/LF-terminated). Dead ends (do not retry): raw `TTY:D` reads, and the wand `BAR:` / `bar*.ldd` decoders (probe expansion slots → `-41`).

**Blocked on / next step:** the OO **message ordinals + parameter structs** for init / set-params / trigger / read. OLIB assigns ordinals dynamically across the class hierarchy (base classes in `olib`/`hwim`), so they resolve only at runtime — capture them with the **SIBO Debugger on the physical device** (remote debug over serial; it supports breakpoints inside DYLs). MAME cannot inject a barcode, so the last mile must be on hardware. Full step-by-step is in `code/inventory/CONTINUATION.md`.

**RE toolchain (reproducible):** the ROM is MAME machine **`psionwamx`**; run its debugger headless via `xvfb-run -a mame psionwamx -rompath roms -debug -debugscript CMDS -sound none -seconds_to_run N` (MAME lua input injection into the keyboard matrix does NOT work headless — a known limitation). Static: **radare2** (16-bit x86). Decompile: **Ghidra headless** (processor `x86:LE:16:Real Mode`, a Java GhidraScript — Ghidra 12 has no bundled Python). Get MAME/radare2/Ghidra via `nix-shell -p ...`. Details in `docs/mx-re/toolchain-and-plan.md`.

**Fallback to deliver value now:** Phase 2 (the DBF inventory: add stock, consume by quantity) can be built with keyboard UPC entry against `docs/reference/05-filesystem-dbf.md`, dropping the scanner in behind the same interface once retrieval is finished. [[docs-keep-updated]]
