XMI goodies?

[Sridhar Ayengar]

Ian Viemeister wrote:
> On Fri, 9 Mar 2007, Ethan Dicks wrote:
>> 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.
> 
> Close...  The bus you're describing there is the LSB bus, which can handle
> up to 8 CPU or memory modules (1-6 CPUs, VAX or Alpha; 1-7 memory modules,
> up to 3.5GB on VAX), and one dedicated slot for the IO module.

Nope.  It applies to the XMI bus in the VAX 6000 too.  If you max out 
CPU's you can't max out RAM.

> The IO module connects to 1-4 XMI card cages which handle Ethernet, DSSI
> (VAX only), SCSI (Alpha only), CI, and a bridge to VAXBI.

Not only those, but on Alpha, you can hook to PCI and (IIRC) Futurebus+.

>> 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.
> 
> Well, they ship with a 3-phase input, but each of the three power
> regulators is a simple single-phase load.  If the machine isn't loaded
> with extra cards and storage PIUs, it can be run from a single regulator.

Actually, you can max out the entire machine and run on a 220V + center 
tap dryer plug.  I know it can be done because I've done it.

Peace...  Sridhar