PCI floppy controller

[Chuck Guzis]

On 4/23/22 07:16, Liam Proven wrote:
> On Fri, 22 Apr 2022 at 23:41, Chuck Guzis <cclist at sydex.com> wrote:
>>
>> Take a look at the chip (DP8473) datasheet.   It boasts direct (no
>> buffer needed) support of up to 4 drives.   The rest is software; the
>> protocol is pretty much write some registers before/after
>> writing/reading to the buffer memory.  In other words, it's a low-level
>> interface protocol; there's really no intelligence in the unit.
> 
> TBH, I wouldn't know. I'm a software type at best. Interesting info, though!

An interesting aside is that on Adaptec and Future Domain SCSI ISA cards
with the NS chip, it's quite possible to run an additional wire between
the chip and the floppy header and get 3 floppies on a single cable.
DTC and Ultrastor used the "twisty twisty" cable on their cards to do
the same.   There also was a DTC (ESDI or SCSI, I don't recall) ISA card
that, with a jumper allowed one to run 4 floppies on single "flat"
ribbon cable.  Each drive had its own drive select (0,1,2,3) and all
drive motors ran at the same time, but it worked.

--Chuck