KL-10B in DEC-20 [was RE: Who's rewired their house for this hobby?]
RichA at LivingComputerMuseum.org
Wed Nov 26 19:27:45 CST 2014
From: Noel Chiappa
Sent: Wednesday, November 26, 2014 4:43 PM
>> From: Rich Alderson
>> We have a non-running 1090 here at the museum
> Oh, good, then you have a machine to run ITS on (along with ones for WAITS
> and Tops-10! :-)
Yes, we do, but not that one. "It's dim, Jed."
> Just kidding (mostly); ITS did run on a KL (without hardware mods), but I'm
> not sure which model it was; it was a pretty early one.
ITS ran on exactly 1 KL, MIT-MC. It was a "Model A" system, probably a KL10B
but I'd have to ask the owner. It's currently in storage in Sweden.
> I know it had the external memory bus, and I _think_ it had the RH20s (I
> know it had RP's of some kind, I think MassBus, because one of them was
> dual-ported and the console 11 booted off of it, and I don't think it had
> whatever PDP-10 disk controller the KA's had). I guess it was a KL-B, then?
All KL10-based systems have RH20s. The front end 11/40 has an RH11, and one
disk (at least) has to be dual-ported between the front end and the -10.
> Whichever one it was, anyone who wanted to run ITS on a KL would probably want
> the same model - I know ITS had custom microcode (in part to emulate the MIT
> pager, which had a different page size from the BBN/DEC one, and also because
> ITS used some custom instructions which had been added to the KA's), and
> although one could probably get that to run on a different model KL, it might
> be (an unknown amount of) work.
Yeah, I've thought about how much work it would be. I'd prefer to start with
the MC system if I were going to run ITS on a KL.
> But, completely seriously, ITS is an amazing system, and although there are
> a few running on simulators, I'm not sure anyone has it running on real
> hardware. That would be Very Cool.
I agree. As I noted in my response to John Wilson, I'm working on it. :-)
Vintage Computing Sr. Systems Engineer
Living Computer Museum
2245 1st Avenue S
Seattle, WA 98134
mailto:RichA at LivingComputerMuseum.org
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