8 Nov
2001
8 Nov
'01
7:22 a.m.
Yes, and the Siemens drive with the lead screw looked VERY much like the
Micopolis drive, IIRC. The split-band actuator (tendon drive) was eventually
found to be the best tradeoff between cost, precision, reliability, and
performance.
I don't think I ever owned a minifloppy drive with a lead screw, but was quite
surprised to find it in the Siemens tech manual.
Dick
----- Original Message -----
From: "Fred Cisin (XenoSoft)" <cisin(a)xenosoft.com>
To: <classiccmp(a)classiccmp.org>
Sent: Thursday, November 08, 2001 10:45 AM
Subject: Re:head-positioners - (was Apple Floppy Drives (was: More Apple
Pimpers))
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.