7 Apr
1999
7 Apr
'99
11:32 a.m.
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(a)xenosoft.com
XenoSoft http://www.xenosoft.com
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