12 Oct
2006
12 Oct
'06
12:39 p.m.
Don wrote....
The issue is there are two different aspects of the
UNIBUS that are being
terminated:
Aha. Now that makes sense! Thank you :)
What that means to me then is that in the /34 the 9302 should only be
plugged in to a the AB unibus out slot and NOT in a MUD slot, otherwise, you
get a funny smell I bet :)
So what about the 9312 in the /34 then. I assume it can only (no matter HOW
it's jumpered) be put in a MUD (AB) slot, never in an AB unibus slot (Unibus
in or Unibus Out). ??
Then, this of course brings me back to my dearly beloved (sarcasm) /45. In
that machine, the cpu doesn't terminate anything from what I understand,
hence the 930 at the front in slot 1AB. I assume in the /45 then, you CAN
put the (appropriately jumpered) 9312 in the last slot (unibus out), and
that you don't put another 930 in that slot and put the 9312 in a prior AB
slot. Is that all correct?
Thanks so much!
Jay
12 Oct
12 Oct
1:51 p.m.
Jay West wrote:
Don wrote....
Correct ... the M9302 terminator is a UNIBUS slot device.
The difference between the AB UNIBUS vs the AB MUD (Modified UNIBUS) is
that AB UNIBUS has grounds and BG1_H~BG4_H,NPG_H on pins that AB MUD
uses for +20V core, -15VBB, +15VBB and some internal SPC slot parity
signals.
The issue is there are two different aspects of
the UNIBUS that are
being terminated:
Aha. Now that makes sense! Thank you :)
What that means to me then is that in the /34 the 9302 should only be
plugged in to a the AB unibus out slot and NOT in a MUD slot,
otherwise, you get a funny smell I bet :)
So what about the 9312 in the /34 then. I assume it
can only (no
matter HOW it's jumpered) be put in a MUD (AB) slot, never in an AB
unibus slot (Unibus in or Unibus Out). ??
You wouldn't want to put in in the
UNIBUS out. You still need to
terminate both ends of the bus, you want an M9302 somewhere to process
SACK timeout, and you can have at most one M9312 in the system. So the
only config that meets all these is M9302 in 9AB, and M9312 in 3AB.
Then, this of course brings me back to my dearly beloved (sarcasm)
/45. In that machine, the cpu doesn't terminate anything from what I
understand, hence the 930 at the front in slot 1AB. I assume in the
/45 then, you CAN put the (appropriately jumpered) 9312 in the last
slot (unibus out), and that you don't put another 930 in that slot and
put the 9312 in a prior AB slot. Is that all correct?
This I will have to defer to someone else. The M9312 doc's indicate
there are jumper wire settings (W1-W12) to allow it be in either a MUD
(standard position) or for 'other UNIBUS CPUS with M9312 in place of
M930'. I would assume this to mean that one of the M930s (which I assume
is the 'old' M9302 without the SACK timeout logic) can be replaced by a
correctly configured M9312, but you still need the other M930 at the
other end of the bus.
Or, just speculating here, what about an M9312 at the front of the bus,
and an M9302 at the end of the bus (kinda like the 11/34 config)? This
would require some research to make sure it doesn't smoke anything.
Caveat emptor to be sure.
Thanks so much!
Jay
2:06 p.m.
________________________________
Van: cctalk-bounces at classiccmp.org namens Don North
Verzonden: do 12-10-2006 22:51
Aan: On-Topic and Off-Topic Posts
Onderwerp: Re: Unibus Termination KnowledgeQuest
Jay West wrote:
Don wrote....
Correct ... the M9302 terminator is a UNIBUS slot device.
The difference between the AB UNIBUS vs the AB MUD (Modified UNIBUS) is
that AB UNIBUS has grounds and BG1_H~BG4_H,NPG_H on pins that AB MUD
uses for +20V core, -15VBB, +15VBB and some internal SPC slot parity
signals.
The issue is there are two different aspects of
the UNIBUS that are
being terminated:
Aha. Now that makes sense! Thank you :)
What that means to me then is that in the /34 the 9302 should only be
plugged in to a the AB unibus out slot and NOT in a MUD slot,
otherwise, you get a funny smell I bet :)
So what about the 9312 in the /34 then. I assume it
can only (no
matter HOW it's jumpered) be put in a MUD (AB) slot, never in an AB
unibus slot (Unibus in or Unibus Out). ??
You wouldn't want to put in in the
UNIBUS out. You still need to
terminate both ends of the bus, you want an M9302 somewhere to process
SACK timeout, and you can have at most one M9312 in the system. So the
only config that meets all these is M9302 in 9AB, and M9312 in 3AB.
Then, this of course brings me back to my dearly beloved (sarcasm)
/45. In that machine, the cpu doesn't terminate anything from what I
understand, hence the 930 at the front in slot 1AB. I assume in the
/45 then, you CAN put the (appropriately jumpered) 9312 in the last
slot (unibus out), and that you don't put another 930 in that slot and
put the 9312 in a prior AB slot. Is that all correct?
This I will have to defer to someone else. The M9312 doc's indicate
there are jumper wire settings (W1-W12) to allow it be in either a MUD
(standard position) or for 'other UNIBUS CPUS with M9312 in place of
M930'. I would assume this to mean that one of the M930s (which I assume
is the 'old' M9302 without the SACK timeout logic) can be replaced by a
correctly configured M9312, but you still need the other M930 at the
other end of the bus.
Or, just speculating here, what about an M9312 at the front of the bus,
and an M9302 at the end of the bus (kinda like the 11/34 config)? This
would require some research to make sure it doesn't smoke anything.
Caveat emptor to be sure.
Thanks so much!
Jay
Well, I learned a lot from this.
I know that I have a working 11/35 (/40 OEM) which has an M9312
in the last slot (unibus-out). That was 3 years ago, and when I am
up to inspecting the /35, I will sure check the M9312 jumpers!
The 11/35 documentation mentions M930 as terminator at the "far"
end, and I (in my ignorance some years ago) said, just like Jay, "hey,
the M9312 is also a terminatoe, so...". The bottom line is that my 11/35
did work with the M9312 at the far end of the unibus, and that I could
start the system, and enter "DL" to boot from RL02.
Now, if everything was electrically correct (for example not terminating)
is something I will certainly check when I get to it.
thanks for all the shared information!
- Henk.
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13 Oct
13 Oct
7:52 a.m.
Henck wrote....
I know that I have a working 11/35 (/40 OEM) which has
an M9312
in the last slot (unibus-out). That was 3 years ago, and when I am
up to inspecting the /35, I will sure check the M9312 jumpers!
The 11/35 documentation mentions M930 as terminator at the "far"
end, and I (in my ignorance some years ago) said, just like Jay, "hey,
the M9312 is also a terminatoe, so...". The bottom line is that my 11/35
did work with the M9312 at the far end of the unibus, and that I could
start the system, and enter "DL" to boot from RL02.
Now, if everything was electrically correct (for example not terminating)
is something I will certainly check when I get to it.
Henk, I believe you are right. The /35 doesn't have the cpu doing this
("partial") termination like the /04 and /34 does I don't think. So your
situation for termination is likely to be more similar to mine in the /45...
where you typically have a M930 in slot 1AB, and then another M930 in the
last unibus out AB slot. To install a M9312 in one of those type of systems,
I believe you can replace one of the M930's with the 9312.
Given that my background was the /45, I found the situation with the /34
most confusing - hence my post to the list.
Jay West
6649
days inactive
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3 comments
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participants (3)
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ak6dn＠mindspring.com -
henk.gooijen＠oce.com -
jwest＠classiccmp.org