Prototype IBM DemiDiskette drive

[Chuck Guzis]

On 08/22/2018 01:31 PM, Eric Smith via cctalk wrote:
>

Re: Shugart 5.25" floppy

> Instead of being built on an aluminum casting, it only had bent metal. The
> head stepping mechanism worked like an 8-track tape. It used a solenoid to
> advance one track inward; the only way to go outward was the next step from
> the innermost track returned to the outermost (track 0). The single track
> step time was incredibly slow; I think it was around 750ms, vs 40ms for an
> SA400.

If done right, there's nothing wrong with sheet metal.  The early
Micropolis 5.25" drives were built that way and were surprisingly heavy
and expensive.  Eventually, Micropolis went to a cast body, sort of like
everyone else--but not quite.  Rather than having the positioner
(stepper and leadscrew) attached to the main body, it was attached to
the movable "latching" part, which was also cast.

Then there was the early Teac with a plastic (resin?) body...


--Chuck