Never Mind: MicroVAX 3

From: Jerome Fine <>
Date: Mon Sep 6 14:30:19 1999

>Zane H. Healy wrote:

> I solved my problem. Moved the TQK50 to the next row after the RQDX3,
> instead of beside it and it works fine. Don't quite understand that, since
> I'm positive I had the RQDX3 and TQK50 in the exact same spot with the
> KA650 board set as they'd been with the KA630 board set, and I saw it
> working in that config.
> Does a system care if you've got a grant continuity board in a spot that
> you shouldn't have a board? It seems to me that it should.

Jerome Fine replies:

I saw some of the configurations and at first glance, it does seem as
if the Sigma backplane is "ABCD" all the way. However, one method
of testing that without taking any chances may be to add a few more boards
to the "AB" side all the way down and see if they still function. If only the
first 4 slots are "ABCD" and the 5th slot starts the "ABAB", then the second
part of the 5th slot will require a bust grant to allow any interrupts to get to the
CPU. If the 5th and 6th slots and both "ABCD", then putting a single bus
grant card in the "AB" side of the 5th slot will allow the 6th slot to function.
Suggestion: Put a bus grant card in the 5th "AB" slot and move the TK50
(or the RQDX3 - actually, I suggest it be the RQDX3 since you will not
even be able to boot and you will find out immediately) down to the 6th
slot. Tim, is this suggestion a safe way to find out? In general when doing
such testing, look for a safe way to test so that if you are making an
incorrect assumption, nothing will be damaged - it just will not work.
If the first 6 slots are all "ABCD", then probably the rest are as well. If
the Sigma box is running a uVAX II (or higher), I believe that "ABCD"
slots are required for the CPU and the memory. Tim is that correct -
I don't have any uVAX systems? But I do have ONE SMS Qbus box
which I believe is "ABAB" starting with the first slot and ran a dual
11/73 with memory beside it - if I remember correctly.

ALSO, I am about to try out (if I can get a degausser) some TK50 tapes
in a TK70. But I want to be able to have both the TK50 and a TK70
tape drive on line. I have done a SYSGEN and the MUX.SYS device driver
allows two devices, (MU0: and MU1:), but I don't have the dip switch
settings for alternate CSR values. Can anyone help? PLEASE?

Sincerely yours,

Jerome Fine
Received on Mon Sep 06 1999 - 14:30:19 BST

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