12" Floppy Disks

[Eric Smith]

On Tue, Sep 15, 2015 at 2:39 AM, Adrian Graham
<binarydinosaurs at gmail.com> wrote:
> I've been contacted by a teacher who's looking for any information about
> 12" floppies. Am I imagining that they really existed? I'm sure I've seen
> one or seen adverts for them, maybe at Bletchley Park. Others he's
> contacted think he's getting confused with 12" laser discs but I'm not so
> sure.

When IBM introduced the floppy disk in 1971, they were 8-inch, and
that became industry standard, partially supplanted by 5 1/4" when
Shugart introduced those in 1976, then 3.5" introduced by Sony and HP
in 1982. There were a few other oddball sizes like 4", 3 1/4", 3", 2
1/2", and 2", but none of them were very successful. The market
pressure was always to reduce the size of the medium, so I can't
imagine why anyone would have made 12" floppy disks.