PDP-11/05-NC with M9301?

Mattis Lind mattislind at gmail.com
Thu Mar 17 10:24:04 CDT 2016

2016-03-17 15:24 GMT+01:00 william degnan <billdegnan at gmail.com>:

> >
> >
> >
> > If one read notes in the PDP-11/04 printset it says: Do not insert a M930
> > or M9302 in a MUD slot. Only in the Unibus slots or you will have short
> > circuit. On the other hand it does not say that the M9301 (or M9312)
> cannot
> > be installed in a unibus slot. It recommends that those boards go into
> > slots. But electrically I cannot see that it shouldn't work. Especially
> if
> > you jumper W1 - W5.
> >
> >
> Once I tried putting a M9312 into the backplane of my 11/05 NC.  The M9312
> did not boot to the console monitor, but there should be a way to do it, I
> just did not find it.   I have an expanded backplane.  If you look at the
> M9312 or M9301 you can surmise that these are not going to do anything like
> what the M930 does

In what slot did you put the M9312 in your 11/05 NC? In a MUD slot in the
Unibus expansion bus? Did you remove any of the other M930 boards then?

The M9312 and M9301 are nearly identical except for the way how the ROM
addressing takes place.

I would say that M9312 and M9301 has all functions of the M930 plus some
additional functions. They are bus terminators all of them. But M9301 and
M9312 has built in ROM and bootstrap logic whereas the M930 has not. The
M9302 on the other hand is a terminator plus the SACK logic.

> M930:
> http://vintagecomputer.net/digital/pdp11-05/EM_8Kx16_Planar_Memory_companion_card.jpg
> The M9301 is a ROM card, just like the M9312, one is an older model and
> they're compatible roughly I believe.  I recall from the manual that one
> could use the M9301 in an 11/05, but was not able pursue if it works yet
> for my set up.  I will eventually check this, but if there is a test you'd
> like me to try send and I will fire up the system.  I have the manual, I'd
> want to read up on it first to be sure I am installing correctly.  Not sure
> what ROM is installed on the card I have.
> b
> --
> @ BillDeg:
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