Question about UNIBUS terminators, M9300

[william degnan]

>
>     > There are jumpers on this card. W1, W2, W. I did not find any
> specific
>     > examples online of scenarios for the jumpers
>     > ...
>     > I think I get why one would remove the W2 jumper but if W1 is removed
>     > (open) instead can someone give me an example scenario for when you'd
>     > want to use this card "for beginning of non processor bus
> termination".
>     > Can someone give me an example of when you'd do this?
>
> The device the M9300 was invented for was probably the RH11-AB, which is
> where one most often finds them. The RH11 is an UNIBUS device which is a
> MASSBUS controller; the RH11-AB has connectors for _two_ UNIBI (so one
> RH11-AB can be 'in' two PDP-11's at the same time; i.e. all the devices
> connected to that controller can be accessed from either machine).
>
> If it's only connected to a single CPU, though, what does one do with the
> second UNIBUS? That's where the M9300 comes in. It simulated the
> NPG-granting
> section of a CPU, and when jumpered to do that, it goes at the _start_ of a
> UNIBUS - e.g. the second UNIBUS in the RH11-AB. (Leave all the jumpers in,
> and it functions like an M930, and can go at either end).
>
> You can find a description of its use in the RH11-AB, as well as a
> description of how the M9300 works, in the "RH11-AB Option Description"
> document (available online), starting on page 4-32.
>
> I can't conceive of any use for one in most PDP-11's, though (outside an
> RH11-AB, of course).
>
>         Noel
>

OK.  Yes, the system I have was set up for RH-11.  Here is the layout
starting from slot 9/11 of the expansion cabinet of the 11/40 I am working
on

9/11: M9202 (1-2)
11: M7297 (3-4)
11: 7296 (5-6)
12: M7295
13: M7294
14: M5904 (3-4)
15: M5904 (3-4)
16: M5904 (3-4)
17: GC (4)
18: GC (4)
18: M9300 (1-2)
19/21: M9202 (1-2)
19: GC (4)
21: M7248 (3) M7212 (4) M7212(5)M7212 (6)
22: M784 (5) M783 (6)
23: M7213 (3-4) M785 (5) M785 (6)
24: EXPANSION CABLE (1-2)
24: "small card" (4), M785 (5) M785(6)
26: M9700 (3), M105 (4), M7226 (5-6)
27: M7821 (4)
28: M117 (4)
29: M002 (4)
31: CABLE FROM 24
31: M7258 (3-6)
32: M8094
33: M8098
34: M7800 YA (3-6)
31: -
32: -
33: -

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