Format for IBM display writer disks??

From: Wayne M. Smith <wmsmith_at_earthlink.net>
Date: Fri Jan 19 01:36:03 2001

> > My S/23 manual says the following:
> >
> > "The location of the access hole for index sensing
on a
> > diskette [type] 1 differs from that on a diskette
> > [type] 2 and diskette [type] 2D." The 31SD drive
can
> > only read type 1, so I guess you could say it's
soft
> > sectored (I assume it ignores the hole). The 51TD
> > reads types 2 and 2d, which have the same hole
pattern
> > vis-a-vis each other, but different from a type 1,
but
> > also reads type 1. It distinguishes based on the
> > location of the index hole, so I would say it was
hard
> > sectored. Then again, in effect it's only
determining
> > DS vs. SS so maybe that's not the same thing. What
do
> > you think?
>
> Wayne, what they are discussing is the aperture in
the disk
> jacket that permits seeing the index and/or sector
holes.
> On the Single-Sided disks that aperture is 7degrees
clockwise
> from 12 0'clock. On the Double-Sided disks it is 26
degrees
> clockwise. Double-Side drives have sensors in both
positions
> and can therefore read either single or double sided
disks.
> On the other hand, Single-Side drives have only a
single sensor
> at the 7 degree position.
>
> In a Hard-Sector 8" disk there are 32 evenly spaced
sector holes,
> plus 1 index hole that is centered between two of the
sector holes.
> To all intents and purposes, the only difference
between a single
> and double sided Hard-Sector disks is the location of
the aperture.
>
> - don
>
>
I learn at the feet of the master. Thanks.

-W
Received on Fri Jan 19 2001 - 01:36:03 GMT