XMI goodies?

Doc Shipley doc at mdrconsult.com
Fri Mar 9 22:16:19 CST 2007

Ethan Dicks wrote:
> On 3/9/07, Richard <legalize at xmission.com> wrote:
>> In article <45F21FCE.8070603 at mdrconsult.com>,
>>     Doc Shipley <doc at mdrconsult.com>  writes:
>> >    Is there any interest here in DEC XMI gear?
>> I haven't the foggiest idea what XMI gear is :-)
> I should probably let Doc chime in here, but I can't resist... it's
> the CPU/memory bus used in late-model DEC VAXen like the VAX 6000
> line.  One stuffs a few CPUs, some memory, perhaps some network or
> cluster controllers and maybe a VAXBI cage or two on the XMI bus and
> you have a fully-loaded VAX 6xxx (where the exact model number is a
> product of the number and speed/variety of the CPUs).  If I remember
> correctly, one may stuff up to 6 CPUs on the XMI bus, which is limited
> to a smallish number of total slots), but if one wants to max out the
> memory and have other peripherals in there, it might not be possible
> to have all 6 CPUs loaded.

   No, please, you know way more about 'em than me.  I've never run 
these, although they were running till the day before I took them.  I 
uncabled them on the datacenter floor, and they've been stored gently 
since.  I picked up only because there were machines in the lot that I 
did want.

   If you google "technical specifications DEC 7000" there's a pretty 
detailed description of the laserbus/XMI scheme out there in pdf.

> Interesting stuff, if you want to run a VAX the size of a
> refrigerator.  The last one I saw in the wild was a few years ago, but
> there are quite a few in hobbyist hands.  Someone (here?) has
> described how to run one off of either single-phase or US 220VAC, but
> they shipped from DEC with 3-phase power, IIRC.

   The floor cabinet models are 3-phase, but the rackmount system unit 
and the RM XMI crate are both 200-240VAC single-phase.  The standard 
plug is a NEMA 6-15, so I'd guess it's not pulling more than 10A-12A peak.


   A whole system, including processor, XMI cage, and a half-dozen 
BA350s, will fit in a full-height rack.


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