On Sun, 31 Oct 2021, Chuck Guzis via cctalk wrote:
Gene, are you certain that these aren't
"flippy disks" (two index
apertures)?
And, if you punch a THIRD hole, then the disk could be used DS, OR Flippy!
One of my first products to market, the "Berkeley Microcomputer FlipJig",
was a plexiglass "pocket" with holes, for marking diskettes for punching
the extra holes.
The "deluxe" model had a stub spindle on the outside and a ring, for
putting on hub reinforcers.
The 8" model had provision for marking either the DS hole or the SS hole.
So, I did have a few DS/Flippy 8" disks.
The 5.25" one was, of course, obsolete as soon as DS 5.25" drives became
popular (PC-DOS 1.10).
I used to have some mimeographed instructions, that were purportedly
put out unofficially by somebody in IBM, for a patch to PC-DOS 1.00
for use with DS drives, that trested the second side as if it were ANOTHER
drive!
--
Grumpy Ol' Fred cisin at
xenosoft.com
XenoSoft
http://www.xenosoft.com