8" drive on a pc controller

From: Lawrence LeMay <lemay_at_cs.umn.edu>
Date: Wed Apr 14 15:14:05 1999

Well, I'm about to start making various custom ribbon cables, for
hooking a terak disk drive to a pc controller, to connect a
DSDD 8" drive to a pc controller, and to connect a 5.25" drive
to a 8" controller (cromemco).

As I dont have all the necessary connectors yet, my first attempt
will be hooking a terak drive to my PC. I have 3 different
documents all describing this sort of thing, and it looks like
you have to read carefully and consider exactly what you're trying
to connect, in order to get a few of the lines connected correctly.
Thats fine, i'll see if i can figure that out.

One thing concerns me though. My oldest document mentions using
pull-up resistors connected to a +5 source, on 11 of the connections
on the 50 pin side. The explanation is that some signals are open
collector driven, and thus you need 2200 Ohm pull up resistors.
Does anyone know what the deal is, and is this really necessary, or
just a nice idea that you can usually ignore...

-Lawrence LeMay

PS: The terak drive is a SSSD shugart, and it has a 40 pin external
connector on the case (they dont bother connecting the first 10 pins).
Received on Wed Apr 14 1999 - 15:14:05 BST