I'll necro an old thread, just for the sake of this page being indexed by google, and people landing here, even if the OP never reads it.

I've seen similar cards, but not that specific card.

It's a 'ROMDOS' card. Usually a 1mb or so ROM, that maps into the adapter rom region, and then has some latching circuitry to page parts of itself in and out of that owned chunk of address, that responds using an int13h handler routine.

Contains a version of DOS and some mission critical files for early embedded computer applications. You mentioned PoS, but other uses included xray machines and metal detectors (like airports use.) along with scientific and medical equipment.

This is such a similar card.

The one you have appears to have a battery, so it may be a hardware ramdisk, rather than a rom-dos card.

There were a lot of 'bespoke' (custom made) boards back then, so finding exact data may be difficult. I'd suggest using an FCC-ID search, if you can find the fcc-id on the card.

A quick peek inside the romdump suggests a csrd ID and a manufacturer.

"Copyright (c) 1993,94 by MTB GmbH - RAM-/ROM-Disk RARODI-1 V1.3"

MTB GmbH makes aerospace and scientific equipment, and still exists. No current public facing data exists on this old product that I can find.

The identity string in the dump suggests a writable ramdisk with a romdos backing.

You might wtite to MTB GmbH, and see if they have any product documentation/utilities in their archives.

The KM681000BL chips are 128K SRAM (x4 = 512K total), and they're -L variants with low standby current (probably preserved by the battery) so those are probably used for a static ramdisk. Which I guess doesn't really make it a ramdisk at all.

I have some sort of similar ISA card that boots NT4.0, I posted a picture and links here: Re: Bought these (retro) hardware today

That, (your RW-XT-001), is basically an IDE hardcard, but with a compact flash module baked on instead.

CompactFlash is designed to be electrically identical to IDE.

That makes it more useful than a paged ramdisk, like this is, as it can work with any OS that knows how to communicate with an IDE controller. (In your case, NT4.0)

A poor-man's version can be made with a 90deg header and a CF->IDE adapter slapped onto any period 8bit IDE controller. (Or by putting a Disk-On-Module [DOM] directly on the IDE port of said card.)

ROMDOS cards are different beasts. They are memory-mapped IO devices with the equivalent of a bootable option rom, like a pxe bios, or like the bios in an xt-ide uses. This rom takes over boot, inserts its hook into the int13h vector so dos disk access requests get handled there, and then likely uses 'write on rom' style banking to intercept a message bound for the card, to drive its latching chips. A chunk of the memory addressed option rom is used as the IO 'window' through which data io operations are trapped by the latching chips. This causes this portion of address to get moved around to parts of the ROM present, based on some control method. (Could be 'write a magic word to an io port number, could be 'write on rom' paging.)

The romdump of the option rom (which contains the ident string) contains a homogenous block of data, which looks like the area where such writes would be directed.

Since it is ALSO a RAMDISK, it's likely that some portion of the landing area are treated differently than others.

It's more trouble than I want to go through, but it is likely possible to reverse-derive the method of operation just by tracing out the latch circuitry and SRAM/ROMs attached, and where the board's IO traces go.

It boots directly from the ROM, the IDE connection is only needed if using a CF card.
Some pictures and the card specs:

Oh, Neat.

I did not see the "evolved romdos" rom there.

That's a very fancy stacked PCB it has there.

Note that the controller couldn't be presenting itself as standard IDE, since that requires 16 bits and it's only an 8-bit card.
That's also why it probably only supports compactflash and not regular drives; CF supports a special IDE mode that only transfers 8 bits at a time instead of the standard 16.

wierd_w wrote on 2023-07-29, 06:08:

A quick peek inside the romdump suggests a csrd ID and a manufacturer. […]
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A quick peek inside the romdump suggests a csrd ID and a manufacturer.

"Copyright (c) 1993,94 by MTB GmbH - RAM-/ROM-Disk RARODI-1 V1.3"

MTB GmbH makes aerospace and scientific equipment, and still exists. No current public facing data exists on this old product that I can find.

The identity string in the dump suggests a writable ramdisk with a romdos backing.

You might wtite to MTB GmbH, and see if they have any product documentation/utilities in their archives.

Hmm right i saw that but in the past with similar strange items i did get more luck asking community than the corporation / companies about their own products , especially that i would like to change the OS on it to somethink that could be usefull in the future , especially that it is 8bit isa card , could be a real help in testing old PCs .
But i guess cant be hurt by asking the company responsible for it.

I'm gonna be straight with you-- More than likely, the "Treiber" rom is the in13h disk handler, and it probably just handles IO, and should not matter one iota that it is in german. (PC scans for the option rom header byte, begins execution, it inserts itself into the vector table, then performs a disk IO routine call to "Read sector 0" of its block device, and begin executing from there.)

I'd be more interested in the other ROMs, to see if they contain a valid FAT12 or FAT16 filesystem, or if they are some proprietary blob format. If the former, it might be possible to replace the system ROM chips with some baked EEPROMs with an imaged version of DOS.

Looking inside deeper, I find nothing at all like a FAT filesystem header. I dont even find the bootable option rom header!! (well, I DO find hex string 0x55AA but it does not translate into a valid option rom.)

It looks like there are utility programs present in the rom dump however; The tools you are looking for might already be present?
It might be possible to manually hex-edit to "in place bullshit translate" the text strings to "bastard-englishize" the ROM.

I see what data strings refer to as "MTB MINI-DOS EMULATION 1.2"
I believe this to be a very bespoke product, that does things very very uniquely.

Can you boot the machine and run actual DOS programs, like debug? It might be useful to dump the entire adapter region (to try and catch where this thing intercepts boot)

I am thinking it would be necessary to reverse-engineer this card from first principles of operation (by mapping out its mapper logic by tracing out all its IO traces on its logic and ROM/RAM chips), then homebrew your own control code and INT13h handler that then does the needful with an actual FAT12 image.

There is sufficient room on the ROM space for a 320kb floppy diskette image.