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

On Jul 24, 2021, at 5:12 PM, Chuck Guzis via cctalk <cctalk at classiccmp.org> wrote: A very good discussion including the 2M and 2MGUI driver.The author, Ciriaco Garc?a 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