The Last of The Line

[Johnny Billquist]

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