VT103 (was Re: Reviving DEC RX01 power supply)

Jerome H. Fine jhfinedp3k at compsys.to
Mon Sep 10 14:15:26 CDT 2007

 >Roger Ivie wrote:

>> Ethan Dicks wrote:
>> unwarranted.  I kinda fell off the PDP-11 cart in the KDJ11 era, so
>> I'm not as conversant with what's out there... 
> I knew a fellow who claimed to have build a MicroVAX II in a VT103. I
> never saw it and don't know the details, but I believed him. He was
> some sort of meta-service guy at DEC (i.e., he got called when the
> normal service guys couldn't figure it out) and I think the machine
> was on the DEC internal network.  IIRC (and I might not), his name was 
> Ozzie Perez and the node name was OZZIE::

Jerome Fine replies:

I also heard about that system.  I received the impression
that the fellow was in Australia.  The name fits.

The requirement (if I remember what I was told) is that
the CPU and memory must be placed into ABCD slots - which
are standard in the BA23 (the first 3) and BA123 (the first 4)
backplanes.  Since I have trouble even thinking about using
a soldering iron, attempting to set up ABCD slots was just
beyond my ability.  Now software on RT-11 is a different
story for me.  But most everyone who reads this is more
concerned about hardware than software.

As far as I know, the MicroVAX I would have run in a standard
VT103 backplane, but modified to support 22 bit addresses.  So
there may have been a challenge to see if it could be done
with the MicroVAX II.  Anyone know how many amps that CPU
draws on the 5V?  With a 16 Amp limit to the 5V and much less
on the 12V, the VT103 can't support very much.

It was fun to bring in the VT103 (as if it was just a VT100
terminal) and boot RT-11 on the hard disk drive inside.
The only concern was to never move the VT103 around while
the hard drive was spinning.

Sincerely yours,

Jerome Fine
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