RL02 version of UNIX6?

Noel Chiappa jnc at mercury.lcs.mit.edu
Wed Feb 1 14:56:02 CST 2017

    > From: William Degnan

    > 64K. 

That's 64KB, right? DEC used to talk of PDP-11 memory in words, back in the
day, so it's never quite clear unless the 'B' or 'W' is specified.

Anyway, 64KB out to be enough to run most things. I have't looked to see how
big a system with just RL and DL drivers, and a minimum number of disk buffers
(that's probably the easiest way to get the size down almost as far as it will
go) is, but it's probably in the region of 30-35KB (20KB text, and 10-15 KB
data). That leaves plenty for user processes (not max sized, of course).

    > I'd like to get another M7891, mine is only 1/2 populated.

Oh, so that must have been 64KW - 128KB. That will give you plenty of room for
a decent-sized kernel, and user processes. Wonder why it won't boot, then?

Anyway, those are pretty rare. I have a couple of spare M7847's; they're only
32KB, but they'd help. You've got a couple of spare hex MUD slots now in the
DD11-C, right? Speaking of which, where is the M7891 plugged in? It couldn't
go in the DD11-B, or in the CPU backplane?

    > typing anything kills the CPU and I have to restart the system..

Sorry, need exact details: after the '!' prompt, anything you type kills
the system on the first character? Or only "rlunix<CR>" does? How about
"foobar<CR>"? I'd have to look at the bootstrap source, but I think
typing a non-existing file name should take you back to the top-level


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