The LW-30 is a 1985 word processing appliance: a simple Z180 computer with an LCD screen and 3.5” floppy disk drive built in to a daisywheel typewriter chassis. The LW-30 appears to be the French/German version of the WP-1400D. It’s got 64kB of RAM and a 80x14 screen, with an excellent keyboard attached.

It’s not really supposed to boot from floppy but Brother did release a small amount of software for it, including Tetris. I’ve managed to reverse engineer the executable format and have cpmish working on it.

Sadly, this series of typewriters doesn’t use ordinary 720kB or 1440kB DOS floppies — anything but! It’s a custom GCR encoding scheme (implemented in software!) which PC floppy disk drive controllers won’t touch. Luckily you can write these disks with a FluxEngine, but you’ll need to build a $10-15 board to connect a PC drive to to do that. See the FluxEngine Brother documentation for more information. (You’ll need it.)

What you get with this port:

  • about 230kB of storage on a 240kB GCR disk (I have to reserve four tracks for a FAT filesystem to boot from)
  • most of an ADM-3a / Kaypro II terminal emulator supporting 80x14 text
  • a pitiful 38kB TPA
  • a non-interrupt driven keyboard which drops keypresses if the machine’s busy
  • a blinking cursor
  • bugs

What you don’t get:

  • repeat key
  • reliable disk writing (there are bugs here)
  • support for the printer
  • sysgen, format etc
  • no bugs

As you may gather, it’s all a bit fragile.

How to use it

Build cpmish.

Use FluxEngine to write this to a DD 3.5” floppy, using a command line like:

fluxengine write brother -i brotherop2.img

Insert the disk into the machine’s drive, power on, and press FILE to open the disk menu.

Big warning: if you save any Brother files onto the disk, you’ll irrevocably corrupt the CP/M filesystem. Don’t do this.

Press CODE+Q to open the programs menu, and then press ENTER to load and run CPMISH.OP2. After a few seconds the screen will go blank, and after a few more seconds cpmish should start.

To exit, press FILE and the machine will instantly restart (losing all your work).

You can replace the CCP and BIOS with your own if you like, although you do need to do this from Linux (because I haven’t written the CP/M tools for this yet).

Technical details

The machine has a Z180 with 512MB of address space. The RAM is at 0x60000 to 0x6ffff, physical. cpmish lives from 0x65000 to 0x6ffff so as not to step on the Brother OS’s toes, which uses 0x60000 to 0x64fff for workspace; we rely on it to do keyboard and disk handling, as both are complex to use. Hence the very small TPA.

It’d be theoretically possible to dispense with the Brother OS entirely, and access all the hardware ourselves. This would require reverse engineering the details of how the floppy ‘controller’ works; this is done almost entirely in software, so we’d need to reproduce all the code for encoding/decoding flux patterns on the disk, etc; we’d also need to duplicate Brother’s frankly crazy microstepping logic for finding tracks on the disk (the drives don’t have adequate alignment, and make up for it by moving the head a fraction of a track until they get a clean read!).

The terminal emulator is ADM-3a with some Kaypro II extensions, using a custom (drawn by me!) 6x7 font. This appears to be a relatively common choice and most software I’ve tried (Turbo Pascal, VDE etc) works. Sadly, games tend not to work due to the non-standard screen size.


Everything here was written by me, David Given, and is covered under the terms of the whole CP/Mish project. See the documentation in the project root for more information.

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