Coco FDC hacks (was: Ebay reaches new low

From: Roger Merchberger <>
Date: Tue Nov 9 18:43:34 1999

Rumor has it that Fred Cisin (XenoSoft) may have mentioned these words:
>On Tue, 9 Nov 1999, Roger Merchberger wrote:
>> P.S. To keep this on-topic, does anyone have instructions on the hack to
>> convert the above-mentioned floppy controller to be able to handle 3.5" HD
>> floppy drives? I'd *love* to have a 1.44Meg floppy formatted under OS/9...
>> :-) Also, is there any way (without reconstructing the 6 million dollar
>> man...) to get two floppy controllers online using the MultiPak?
>My recollection was that there were several different vartieties. Each
>one will have slightly different issues.

Hmmmm... Looks like I need to grab the controller catalog # (and other
specifics) and keep it in my Palm...

>To add 3.5" HD floppies, you will need to provide a different clock, way
>to change it back and forth, and support for one more signal to the drive.

I know you need a different clock (500Khz signaling rate vs. 250Khz for
double-density) but I'd like to know if it's as simple as a DPDT switch &
another crystal, or are there more things to keep a lookout on (like
different buffers, software changes WRT timing issues, stuff like that...).

>Why do you want to run more than one FDC? If it is to run 4 instead of 2
>drives, you can do that with minor hardware and software hacks to a

Well, IIRC the most drives you can hang off of one controller is 4 SSDD
drives, or 3 DSDD drives because the Side Select signal was used for one of
the drive select pins. (Again, I think... If I'm wrong, please enlighten
me.) I was looking to hang 3 DSDD & 3 DSHD drives off my CoCo... purely for
shits & giggles. If it's a ton of hardware work, "nevermind" comes to mind.
However, if it's some hardware & hacking some device drivers, then... I've
always wanted to hack around with the device drivers of OS-9... :-)

Just musings of random tinkering... ;-)
Roger "Merch" Merchberger
Roger "Merch" Merchberger   ---   sysadmin, Iceberg Computers
Recycling is good, right???  Ok, so I'll recycle an old .sig.
If at first you don't succeed, nuclear warhead
disarmament should *not* be your first career choice.
Received on Tue Nov 09 1999 - 18:43:34 GMT

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