Tu10 pdp11

Johnny Billquist bqt at update.uu.se
Sun Sep 6 08:12:10 CDT 2015

On 2015-09-06 14:38, Noel Chiappa wrote:
>      > From: Johnny Billquist
>      > Early DMA controllers were all multiple cards, so having their own
>      > dedicated backplanes were a pretty sane idea.
> Well, there was also that large intermediate generation which still had their
> own backplanes, but they were 'system unit' (for lack of a defined term for
> this form factor) backplanes (e.g. RK11-D, RH11, etc), which fit into e.g. a
> BA11-K, along with other 'generic' UNIBUS backplanes (i.e. DD11-C, etc).
> That first generation I spoke of (the one with backplanes that mounted
> directly in H960's) are marked by the use of lots of small Flip Chip cards,
> not the larger quad/hex boards that one finds in the 'second generation'
> (above). I guess the larger board versions were cheaper to manufacture, which
> is why they got rid of the first generation ones in favour of the second
> generation (which were often functionally identical to the first-generation
> ones they replaced, e.g. RK11-C and -D).

Hm. Ok. Right. I was actually thinking along the lines of what you'd 
call the second generation then. However, it don't really make a 
difference. If the backplane is small, you can fit it in the same box as 
the rest of the machine. If not, you have it in its own cabinet. The 
principle is the same. You have a Unibus in, and a Unibus out. And 
everything in between is special for that controller. And you normally 
had this for things that did DMA. Simpler controllers usually fit into a 
single slot in a standard Unibus backplane.

I actually used to play with an RP11 once upon a very long time ago, 
which was a full 19" cabinet of its own.

> Those first-generation one used very similar construction technique to the
> KA10 generation of machines, which also used that size Flip Chip (although a
> different series, mostly with individual transistors), and heavier wire on the
> bacplanes. What did KI10's use, does anyone know? I have this bit set that
> they used roughly the same kind of Flip Chips as the 'first generation' PDP-11
> DMA devices, but I've never seen a KI in person.

I have played a little with KA-10 and KI-10. And yes, there are 


Johnny Billquist                  || "I'm on a bus
                                   ||  on a psychedelic trip
email: bqt at softjar.se             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol

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