Hum. I seem to remeber that the max number of RH20 was eight. However two were lost if you
had a NIA-20 and two were lost if you had a CI.
But I might be misremembering.
Johnny
Robert Armstrong <bob at jfcl.com> skrev: (27 februari 2020 00:10:22 CET)
You would
likely have never seen a DTE on a KS processor ?
The DTEs plugged into dedicated slots on the KL. There's no way you
could have ever seen one on another model CPU - it's physically not
possible. The KL could hold up to four DTEs, and the first one was
"special" in that it could poke around in the KLs microstore and
internal datapaths. The 11/40 CFE was connected to that one and that's
how the KL was started up. All the microcode was stored in RAM and
immediately after a power on the KL was little more than a big heater.
The other three DTEs were more general purpose and were used for
communications interfaces.
There was, however, a DL10 for the KI that interfaced up to four
PDP-11s to the I/O and memory busses. Conceptually the DL10 was
similar to the DTE, although I don't know how close they were
programmatically. Of course there was no equivalent to the CFE on the
KI and all four -11 ports on the DL10 were identical. And where as
every KL had at least one DTE for the CFE, the DL10 was strictly
optional.
It's a similar story for the RH20s - they were dedicated options for
the KL only. A KL could have a maximum of 4 RH20s and every one needed
at least two - one for disk and one for tape. Although I believe on
TOPS10 you could mix disk and tape on the same MASSBUS - maybe, I'm not
sure about that.
And likewise there was an RH10 MASSBUS controller for the KI which was
similar to, but not the same as, the RH20.
Bob
--
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