YANU - uVax

From: Megan <mbg_at_world.std.com>
Date: Mon Mar 8 22:25:04 1999

>Thanks Megan!

Any time... glad to help...

>It turned out that when I removed the Viking tape card to inspect it I
>re-inserted it backward (no ears on that one). That meant the RQ11
>wouldn't fit in slot 6 and that meant an empty slot.

Whoops... I've done that once before (*once*)

>Q1) So how badly does it toast things in the Q-bus to be backwards in
>slots A-B ?

>Q2) Do all empty slots need to have bus grant boards?

Let me answer like this...

In a BA123:
        o The Qbus passes direct from slot1/ab to slot4/ab
        o For slots 5-12, it does the serpentine (4/cd, 5/cd,
                5/ab, 6/ab, 6/cd, etc)
        o All dual boards must be placed at some point in the
          serpentine. For slots 1-4, this means AB. For
          slots 5-12, this can be either AB or CD.
        o Quad boards which are not for CD, must go in slots
        o For quad boards which can be either CD or Q/CD, the
          jumpers on-board must be set for the slot you are
          placing it in (there should be a couple of jumpers
          which are removed if the board is placed in a Q/CD
          slot, and installed if it is placed in a Q/Q slot)
        o For quad boards which can only go in Q/Q, they may
          only be placed in slots 5-12.
        o If you follow the serpentine, there should be no
          empty Qbus slots between the processor and the last
          board in the bus (there are exceptions, but for now
          regard it as a hard and fast rule).
        o For any gaps in the serpentine, you should install
          a M9047

That's it in a nutshell. For a BA23, the critical numbers are
slots 1-3 == Q/CD, 4-8 == Q/Q

                                        Megan Gentry
                                        Former RT-11 Developer

| Megan Gentry, EMT/B, PP-ASEL | Internet (work): gentry!zk3.dec.com |
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Received on Mon Mar 08 1999 - 22:25:04 GMT

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