8 Nov
2001
8 Nov
'01
1:45 p.m.
Richard Erlacher wrote:
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.
Wasn't the Osborne I floppies Siemens?
Eric
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.
>
>