I don't know about designators, but the first mini-floppy drives I got all
had lead screws like the 8" drives. Later on, the SA400-<something> became
available, and I don't remember what the <something> was, but they had the
helical cam with a 2-phase stepper.
Dick
-----Original Message-----
From: Fred Cisin (XenoSoft) <cisin_at_xenosoft.com>
To: Discussion re-collecting of classic computers
<classiccmp_at_u.washington.edu>
Date: Wednesday, April 07, 1999 5:41 PM
Subject: SA-400's (was: Heatkit 5 1/4 floppies
>On Wed, 7 Apr 1999, Richard Erlacher wrote:
>> I don't believe those were the earliest of the 5-1/4" types. The early
>> SA-400's I remember used a lead screw just like the 8" drives, but that
was
>> too costly for the competition that followed. When Apple started buying
>> "partial" drive mechanisms in order to implement their more
software-driven
>> approach, with the idea of saving a few bucks . . . multiplied by a
milion
>> or two drives . . . other manufacturers including SIEMENS and BASF, among
>> others, tried a two-phase stepper on a helically-tracked drive wheel as
>> opposed to the stepper driving a lead screw. Most makers later went to a
>> band-actuator system using a small stepper.
>
>Interesting. All of the SA400s that I've seen used the spiral groove on a
>rotating disc. The only 5.25" drives of that vintage that I have with a
>helical lead screw were the Micropolis 35 track 48TPI and 77 track 100TPI
>(NOT 96TPI!!). Was there any sub model designation for the Shugarts to
>differentiate different positioners?
>
>--
>Fred Cisin cisin_at_xenosoft.com
>XenoSoft http://www.xenosoft.com
>2210 Sixth St. (510) 644-9366
>Berkeley, CA 94710-2219
>
Received on Wed Apr 07 1999 - 20:16:23 BST