Another p112 Query

allison allisonportable at
Thu Dec 6 10:11:18 CST 2018

On 12/06/2018 10:37 AM, David Griffith via cctalk wrote:
> On December 6, 2018 6:42:44 AM PST, Bill Gunshannon via cctalk <cctalk at> wrote:
>> While we are talking about the P122....   :-)
>> Has anyone tried and/or had luck using an 8" floppy drive
>> on the P112?
>> bill
> I haven't tried it myself, but a few of my customers have reported success doing so.
The answer is Yes, if you really understand what your asking.

I've not used the P112 but I have used the combo part in it for FDC
interface and it does/can work with 8", 5.25", 3.5"
drive so long as you get the wiring right as they all differ especially
the 8".   It does do CP/M 8" SSSD format
which was the primary interest (RX01 was secondary and does that too).

The second half of that is the driver for the device as it can do it but
it does have to be programmed.

The combo chip is basically a 765/8272 with 9229 for clock and FDC
interface inside and is not unlike the
37C65/37C765 and remote relations.  Basically it can do any fairly
standard soft sector thing  assuming
its not one of the odd 1771/1773 formats or based on some unique
controller (intel 2D M2FM and RX02). 
The chip used was from the PC world and most people that had issues with
PCs and 8" disks were
trying to work with existing PC FDC drivers limitations.


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