16 Sep
2006
16 Sep
'06
1:30 p.m.
Subject: RE: CompuPro floppy controller differences
From: "Richard A. Cini" <rcini at optonline.net>
Date: Sat, 16 Sep 2006 14:27:00 -0400
To: "'General Discussion: On-Topic Posts Only'" <cctech at
classiccmp.org>
The board has all sorts of jumpers which is good. So I can pick and choose
which ones to change with no problem.
When reading the book it seems that if you want to use a "minifloppy" drive,
there are several components you need to change -- a bunch of resistors, a
crystal and a coil. I presume this is to change the recording frequency and
spindle speed for 5.25" disks. I'm going to try it without modifications
first, but since the HD drive is equivalent to an 8" drive for recording
purposes, I don't think I have to change them.
Those parts are for the Clock, PLL, and write timing. They do not alter
spindle speed as thats the job of the floppy. FYI the 1.2mb floppy appeard
about 6 years after that board was sold.
If you doing 1.2mb 5.25 (or any 8" format) then you DO NOT change those parts.
If you want the conventional 360k two sided (40 track 2S DD) or 720k (80
track 2S DD) then you have to.
Those parts changes are why there was a Disk1A.
As much as I dislike PeeCees, at least they have the
benefit of
standardization.
Ah, it's using the definitive PC FDC. It was developed well before
PCs standardized. PCs however don't offer much choice and if they did
keep all the FDC features you could put a 8" on a PC and read SSSD!
Allison