If anyone is curious about what an IBM 4" floppy
drive looks like, I
just uploaded a picture
and the patent for it to
http://bitsavers.org/pdf/ibm/floppy
http://www.weblog.com/comments.aspx?blogid=30290&postid=71765
4-inch floppy diskettes
In the mid-80s, IBM developed a 4-inch floppy diskette, the
Demidiskette. This program was driven by aggressive cost goals, but
missed the pulse of the industry. The prospective users, both inside
and outside IBM, preferred standardization to what by release time
were small cost reductions, and were unwilling to retool packaging,
interface chips and applications for a proprietary design. The product
never appeared in the light of day, and IBM wrote off several hundred
million dollars of development and manufacturing facility.
CHM appears to have one
http://www.computerhistory.org/collections/accession/X1140.93
Mismarked at 5 1/4" (grrrr..)
And a disk
http://www.computerhistory.org/collections/accession/102667528