On Thu, 28 Sep 1995, Rudderow, Evan wrote:
 
> >SIDEBAR:  Anybody who designed a disc controller for a general-purpose
> >computer system that ends up being irreversibly soldered to the drive mech
> just
> >flunked practical design 101, IMHO.
>
> It's my impression that design features such as soldering the controller
> under the mech are considered good practice from a DESIGN FOR
> MANUFACTURABILITY point of view.  And I'll bet that whomever came up with
> that wonderful idea got a bonus for reducing manufacturing costs.
>
> Maybe the design team should pay a little more attention to the field
> service organization and a little less to the manufacturing organization --
> and maybe they should remember that sometimes things *do* break down.
<snip>
 
Time for a "yeah-buttal".  On the 7925 disc drive, there was a front-panel
switch for the unit number.  Made it real handy to do servicing.  Also
added a failure point.  Unfortunately, a bean-counter got some cheap
rotary wafer switches.  Even MPE found itself somewhat confused when, due
to bouncing of disc drives, the unit numbers were trading around between
read/write operations.
 
As I recall, the two most common failures on the 7925 were the
incandescent "ready" light (for which HP came up with an upgrade kit), and
the unit number switch (which was usually handled either by soldering in a
replacement lousy switch, or hard-soldering a unit number).
 
So whatever HP's reasons to make this change, there _is_ a potential user
benefit from it.  Which may possibly have figured in their decision.
--
         /\--.      John A. Beckett           "Flame the guy, not the list."
        /  \  )     Southern College of SDA   ...adapted from Matthew 18:15
       /----\---.   (615) 238-2701 voice
  \   /      \   \  238-2431 FAX
   `-'        `--'  [log in to unmask]