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

From: Fred Cisin <cisin_at_xenosoft.com>
Date: Thu Nov 8 11:45:18 2001

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.
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 - 11:45:18 GMT

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