[Info-vax] OT: the Daily WTF for today is a VAX/VMS story

[William Pechter]

In article <cld7pc-g5j1.ln1 at news.chingola.ch>,
Paul Sture  <nospam at sture.ch> wrote:
>On 2016-02-14, JF Mezei <jfmezei.spamnot at vaxination.ca> wrote:
>> On 2016-02-14 04:48, already5chosen at yahoo.com wrote:
>>
>>> More I think about it, more the story of VAX hard drive with
>>> three-phase AC motor (in early 90s, non-the-less) appears apocryphal.
>>
>>
>> RA82 drive motors were 1/3 horsepower motors. They were not 3 phase, but
>> required 3 wires in. There was one used to start the motor in the right
>> direction as I recall.  There was some capacitor that would discharge to
>> get motor going. I don't recall the exact details.
>
>I know nothing about the wiring details, but two or more RM05 drives could
>be connected together so that they spun up in sequence to minimise the
>maximum current draw.
>
>And yes, I had a customer who reported that as a hardware error :-(
>
>-- 
>There are two hard things in computer science: cache invalidation,
>naming, and off-by-one errors.

Yup and the RP06's could even share a power socket with a cable DEC shipped
that let a pair of drives daisy-chain the AC power between them.

And a power sequence cable kept them from trying to power up at the same time
IIRC...

Bill
-- 
-- 
Digital had it then.  Don't you wish you could buy it now!
pechter-at-gmail.com  http://xkcd.com/705/