Zendex ZX-200A firmware reverse-engineered

Chuck Guzis cclist at sydex.com
Wed Sep 9 11:19:11 CDT 2015

On 09/09/2015 01:45 AM, Eric Smith wrote:

> Also, the Intel SBC 202 double-density controller uses an
> Intel-proprietary M2FM disk format, instead of IBM-compatible MFM.
> As such, none of the single-chip FDCs are compatible with it, with
> the possible exception of the Western Digital 1781 (with a huge pile
> of external support logic), and (less likely) the TI TMS9909.

You forgot the Signetics 8X330, which, given the date, would actually be 
quite likely and make sense with an 8x30x Microcontroller, given its use 
with early Winchester drives.

AES and HP both, at some point, also used MMFM--and, if I have some time 
to mull it over, I suspect I could come up with a couple more.


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