jnc at mercury.lcs.mit.edu
Tue Jul 9 17:43:51 CDT 2019
> Erom: Eric Smith
Hey, thanks for taking the time to provide all those details.
As you no doubt saw, our emails crossed; I had managed to work out my own
what the difference was. I'd been looking at this page:
and saw the two backplanes, and assumed one was the EBox, and one the
MBox - wrong! But eventually I got it straight...
One some other points you covered:
> The 1080 was intended to replace a KA10 or KI10 ... It only needed a
> single DTE20 for the internal console PDP-11, and it didn't need an
> RH20 because the disk would be attached via an RH10
Got it; makes sense.
Could an -A be upgraded to a -B by swapping the I/O backplane? (Yes, the
wiring to the I/O connectors would have to be changed too, and that might have
been too difficult.) But could the APR handle it (perhaps with one or more
> The -PA and -PV designations .. are for the "arithmetic processor"
> (APR), which is the main CPU portion of the KL10.
Useful terminology to know. Do you happen to know what 'PV' stands for -
or is it just a random letter code?
>> my new theory is that it's the MBox ... that is the
>> difference between the KL10-A and the KL10-B.
> It's not just the MBOX; there are significant EBOX differences as
> well. Various modules from the entire CPU are different, and the
> backplane wiring is slightly different. It was possible to upgrade a
> -PA to -PV by swapping modules and adding some wraps to the
Do note I said "KL10-A and the KL10-B", not 'Model A and Model B'... I
assume the APR's in the -A and -B were identical, it was just the I/O
backplane, etc which were different.
On the -PA to -PV upgrade, could the backplane really be done with some
wraps? I ask because I saw in one manual, talking about a KL10-C to -PV
upgrade, it calls for a backplane swap-out.
I've also got some open questions on the later things like the KL10-R, -PW,
and MCA25, which are not covered well in the documentation avilable in
bitsavers; do you know about the later variations?
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