Distribution floppies (Was: Microsoft OSs (was: Install Floppies)

[Chuck Guzis]

A very good discussion including the 2M and 2MGUI driver.The author,
Ciriaco García de Celis sent me the 2M program sometime around 1994.

It's interesting, and uses 82 cylinders on a DSHD drive and can come
pretty near to 2M.

There was also a 2MGUI (having nothing to do with graphics) version that
could claim to get 2M bytes on a DSHD 3.5" drive in 82 cylinders.   The
way it was done was to Format one 128-byte sector per track with a
length indicator of 16KB.  Obviously, 16K won't fit on a track, so when
writing, the drive was deselected the next time the index came around,
cutting the transfer short. Actually, I think a 200 msec timer was used
for the cutoff.   You didn't get the sector CRC transfered, but you got
what amounts to a full track of data in an odd-sized (not a power of 2)
sector.   Reading, of course, didn't care about the excess data.

That's perhaps the most extreme case I can think of; it's discussed here:

http://www.os2museum.com/wp/floppy-capacity-math/

No way I would ever trust this for archival purposes--and I replied to
the author the same way.  Heck, I wouldn't trust writing on cylinders
80,81, given the quality of DSHD media.

All of this was academic after a bit as Zip, Jaz, Sparq, etc. external
drives became very common.

--Chuck