Reverse-engineering WD1000, WD1001 hard disk controllers

dwight dkelvey at
Sun Nov 20 00:06:36 CST 2016

I suspect Kip had a WD1002. It would have had a BIOS PROM on it. I used one of these on my NC4016 computer. I'd also purchased several 5Meg drives for about $5 ea as DOS no longer supported it. These worked fine for my NC4016. I used this to add new instructions to CM-Forth since the processor had a number of useful side effects. I could recompile CM-Forth in less than 15 seconds. Not that big a deal now days but in the time when the hot Intel processor was a 386, it was quite impressive.


From: cctalk <cctalk-bounces at> on behalf of Rob Doyle <radioengr at>
Sent: Saturday, November 19, 2016 9:31:22 PM
To: cctalk at
Subject: Re: Reverse-engineering WD1000, WD1001 hard disk controllers

On 11/19/2016 5:06 PM, Eric Smith wrote:
> I've been working a little bit off-and-on for years on reverse-engineering
> the WD1000 and WD1001 disk controllers (8X300/8X305-based), and their
> clones.

I have a hard disk controller for my Heath H100 that uses the 8x300.

I didn't realize how common that design was...


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