4 Nov
2006
4 Nov
'06
10:24 p.m.
Zane H. Healy wrote:
At 10:04 PM -0600 11/4/06, Jay West wrote:
You don't need grant cards in the 11/44 backplane slots 9-12 since they
are not SPC slots. The AB portion of the slot is 'extended unibus' EUB
(adds address lines 18-21 for 22b addressing) but the CDEF sections are
not SPC slots. If they are not used for memory they should be left
empty; you can put a grant card (either type) in these unused slots --
it won't hurt anything, but it is not necessary. Empty memory slots
cannot be used for UNIBUS SPC modules either.
Only the last two quad slots 13,14 CDEF in the 11/44 backplane are SPC
and these require G727A/G7273 grant cards depending on whether the NPG
wire has been removed.
The modules have the grant propagation lines intact because they could
*theoretically* go in a MUD (modified unibus, 18b, with associated SPC
section) or an EUB (22b) slot. These modules work in the 11/44
(dedicated EUB memory) slots or the 11/24 (MUD/EUB/SPC slots) which need
grant propagation.
It would appear that the slots designated
"MEMORY" in the 11/44
(slots 9-12 in the *system* backplane) are actually "Extended Unibus"
slots. My reading is that these slots allow 22 bits of memory
addressing instead of 18.
So, of they are still "unibus" slots, does that mean that if there is
one board in slot 9, that slots 10-12 should have grant continuity
cards (G727)?
If they are unibus slots I would certainly think so, but they are
designated for memory only... and I can't find any reference to using
grant cards there for non-populated memory slots.
I'm pretty sure you don't need grant cards, but my /44 is buried. The
/44 can use up to 4MB, and IIRC, I only have 1MB. I needed the grant
cards, but in slots where options had been removed.
It's just like you don't need any kind of grant card in the CPU slots
if you don't have the extended CPU options installed.