On 12/10/17 21:10, Holm Tiffe via cctalk wrote:
This thread is becoming a little confusing. The VAXstation II/RC was a
VAXstation II in a pedestal enclosure
and differed from a normal VAXstation II in only one way: some of the
backplane slots had glue in them.
(OK, two ways, since apparently DEC couldn't be bothered to build a
special backplane with fewer slots
but did think it made sense to produce a new badge with "/RC" on it :-)).
It used a KA630 board just like any other VAXstation II.
As far as I remember there where some restrictions in the cache memory
controller that prevented the use of virtual memory on that restricted
KA620 CPU, not the CPU chip itself.
Now the KA620 was a board that used a modified 78032 uV2 chip
(which I *think* might have been called the 78R32). It differed from
the 78032 in the way it handled page tables (and it may have differed in
other ways too). The intention was to ship something that simply could
not be supported by VMS. Since the limitation was in silicon, there was
nothing that a customer could do to get themselves a cheap VMS box.
The development effort presumably cost a bit more than bunging some
glue in a few backplane slots, but the ROI was probably greater too :-)
I have an ISA Card with a "VAX-Brick" on it, but that was a later
Version with an ordinary CVAX, Cache, SCSI and Network inside w/o those
restrictions. Usually that was meant to run VAXELN.
The VAX Brick (or VAX 4000-50 iirc, that's fifty ... not a typo for five
hundred) was
a full VAX. It was supposed to be an upgrade for the VAX 4000-200.
It replaced the CPU and memory in the original system.
One of the few VAXes I'm pretty sure I've never seen in real life.
It was intended to run OpenVMS. I've no idea whether it also ran Ultrix.
Antonio
--
Antonio Carlini
arcarl...@iee.org
