On October 4, Ethan Dicks wrote:
  I thought that it specifically _was_ the -1.  I
_think_ I have a DEC-
 badged RD-32 (ST-252-1) from a Pro380 VAX 8530 console, but I might
 be mistaken.  Maybe they got what they could get in later years. 
  Probably so.
   The ST251 had
an average access time of 40ms (if memory serves) and
 the ST251-1 was 28.5ms. 
 That sounds right.  Stepper motor vs. voice coil.  (The ST-225 was
 something horrible like 65ms or more; I used to think seek-time didn't
 matter much on a micro, but when I went from 65ms to 28 on my Amiga,
 _wow_!) 
 
  The ST251-1 is a stepper drive also, believe it or not.  They actually
built a stepper positioner that achieved 28.5ms.  Back when it was new
I heard something about them having patented it or something.
  The ST225 was indeed 65ms...scary slow.  It made a great distinctive
"peep-peep" sound, though...which I liked even more than the [still
rather cool] "chirp-chirp" sound of the ST251 and ST251-1. :-)
  I believe the first voice-coil drvie in that family was the ST-4096,
but I'm not positive of that.  That was one nice drive.
       -Dave
--
Dave McGuire
Laurel, MD