On 10/18/2015 10:50 AM, Eric Smith wrote:
Did the disks for the original IBM 23FD "Minnow" floppy disk also
have the sector/index hole near the edge, like the Memorex 650/651?
The Minnow was used as a read-only device for loading microcode, and
the disks were only factory written. I haven't seen an actual Minnow
disk, but since Memorex was one of the companies making
plug-compatible equipment, I wouldn't be surprised if they designed
the 650/651 medium to be mechanically interchangeable with the 23FD
disks.
The Memorex 650/651 supported read/write use, and had more than
twice the formatted capacity of the 23FD, so the on-disk format
clearly didn't match the 23FD.
To the best of my recollection, the Minnow used disks with 8 sector
holes. I don't recall the modulation scheme, but FM would be reasonable.
--Chuck
