Format for IBM display writer disks??

From: Dwight Elvey <>
Date: Thu Jan 18 18:24:55 2001

"Will Jennings" <> wrote:
> Errrm, I have 8" hard-sector disks.. they are used by my Wang 2200MVP..
> which would mean the Nicolet 1080 possibly also uses hard-sector floppies,
> since they share the same floppy disk drives, Shugart 9xx, can't remember
> the number offhand. The DisplayWriter uses the 31SD.
> Will J
> _________________________________________________________________
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Hi Will
 There was nothing special about the SA900's that made them
usable for hard sectored. It is just the controller that cares
about counting index pulses ( I have a Nicolet 1080 ). The
SA900 and the SA800-1 were that same except that the connector
on the 800's are 50 pin and the 900's were 44 pin. The issue
is that the 900 always had a clock separator. Not all 800's
have them.

Note to Don:
 It seems like I remember when trying to figure out what kind
of disk I needed, that there was also a 10 sectored 8 inch
as well as the 32. The only way to tell what kind of controller
one has is to follow the index signal into the controller
and trace out the circuit. If you find some one shots that
have time constants and gating that looks like it would
pick out the disk index from the sector holes, then you
have hard sectored.
 As far as formatting, my machine needed a combination of
setting up registers and some software to get it to work.
This is not always true for all hard sectored setups.
Some just require that you write to each sector so that
there is clocking information. In my case, I needed to
use 32 hard sectored disk that were combined into 2 sectors
of 16 holes each. I also had to have a track number at the
beginning of each track that was written in bit reversed
order. Figuring this out kept me off the streets at night
for a few weeks.
Received on Thu Jan 18 2001 - 18:24:55 GMT

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