Pete Turnbull <pete at dunnington.plus.com> skrev:
On 19/05/2007 11:35, Johnny Billquist wrote:
> "Glen Slick" <glen.slick at
gmail.com> skrev:
> >>> > >PMI memory goes in
slots 1 and 2, CPU goes in 3
> > > From my understanding of this after looking at various manuals
this is
> > > true for an 11/73 or 11/83 with an
H9872 backplane in a BA23
box, but
> > not
for an 11/84.
BA23 is H9278, actually.
Doh! The numbers keep getting twisted around. :-)
> > Correct. So if people could stop assuming
that an 11/84 have a
q-bus, we
> would get
a long way towards clearing this up.
Except that it does have a (short) QBus :-)
Wire-wise, yes. Protocol wise the manuals imply that some signals don't
behave the same, even though they are named the same.
I haven't had time to really analyze this to see what signals actually
change, and in which way, so I'm mostly quoting the manual on this.
OK, we're agreed that the standard config for an
11/83 puts the memeory
before the processor, and the standard config for an 11/84 puts the
memory after the processor :-)
Yes. That we agree on, and that is probably the most important piece.
The P-series 11/84 which I've found described in
one of the later 11/84
manuals used an MSV11-R, which is a normal QBus memory, not PMI.
Well, according to the field guide, that *is* PMI memory. :-) But not
ECC memory like the MSV11-J.
Johnny
--
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: bqt at softjar.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol