Reverse-engineering WD1000, WD1001 hard disk controllers

Eric Smith spacewar at
Tue Nov 22 18:03:45 CST 2016

On Tue, Nov 22, 2016 at 9:14 AM, jos <jos.dreesen at> wrote:

> The MFM disk controller for later version Lilith's is clearly based on a
> WD1001-05.
> But uses a 8x305 iso 8x300.

All of the WD1001 controllers I've seen use 8X305.  Some later WD1000 use
8X305 also.  I've disassembled the firmware of one WD1001-05 so far, and it
does not use any of the added features of the 8X305.

I suspect WD and their licensees switched to the 8X305 due to price or
availability, rather than due to the extra features.

Pic of PCB and dump of proms are on

Thanks! The PROM contents match those of the WD1001-05 which Al dumped and
put online:

Al and I also each dumped the controller PROMs from Fortune 32:16
WD1001-CLB disk controller, which were the same, and appear to be an older
firmware version.

I've made a fair bit of progress reverse-engineering the WD1001 firmware
(newer, not -CLB), and I've just pushed it to the github repo, though it's
not yet as thoroughly commented as the two WD1000 versions (and even those
aren't 100% done).

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