head-positioners - (was Apple Floppy Drives (was: More Apple Pimpers))

From: Don Maslin <donm_at_cts.com>
Date: Thu Nov 8 13:57:29 2001

On Thu, 8 Nov 2001, Fred Cisin (XenoSoft) wrote:

> Micropolis was one of the only ones to use a helical lead screw positioner
> for a 5.25" floppy. VERY SLOW. They also made a 100TPI (not 96) drive.

Tandon also made a 100TPI drive.
                                                 - don

> Starting with the MPI B51, most drives went to a split band positioner.
> In addition to the spiral groove positioner, the SA400 was 35 track,
> whereas all others that followed were 40 track.
>
>
> On Thu, 8 Nov 2001, Richard Erlacher wrote:
>
> > That spiral cam was an attempt to reduce price and mass, I suppose. Like the
> > stone wheel, I imagine it was better than SOME of the other options available at
> > the time, in one respect or another.
> >
> > I don't remember at all (go figure!) what options there were at the time, short
> > of the lead-screw that was used on 8" drives, for moving the heads. I've got a
> > few pictures of Siemens mini-drives (5-1/4") that use lead screws, but I don't
> > remember other vendors using them. Did Shugart make a minifloppy with a lead
> > screw? The old BASF drives that I've cussed from time to time for their
> > fragility at the door latch used that spiral cam arrangement. It was
> > interesting, and, if you worked at it, you could foul it up, since it was
> > readily accessible. Every other scheme I remember from that period used a
> > tendon drive, as did the DS 8" drives, other than Siemens'.
>
> > What do you remember?
> More than I care to.
>
>
Received on Thu Nov 08 2001 - 13:57:29 GMT