Format for IBM display writer disks??

From: Don Maslin <>
Date: Fri Jan 19 00:14:23 2001

On Thu, 18 Jan 2001, Dwight Elvey wrote:

See comments at the end.

> "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
> > _________________________________________________________________
> > Get your FREE download of MSN Explorer at
> 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.
> Later
> Dwight
Fascinating, Dwight! I can well imagine that one had you pulling out
your hair for many hours. Seems there is always the exception that
disproves the rule.

Looking at my 3M Diskette Reference Manual - circa 1990 - it speaks
only to the 32 hard sector disks. But it does not address the ones
that had the sector holes near the circumference either.

                                                 - don
Received on Fri Jan 19 2001 - 00:14:23 GMT

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