PDP-11/45 RSTS/E boot problem

Noel Chiappa jnc at mercury.lcs.mit.edu
Mon Feb 11 15:17:18 CST 2019

    > From: Jerry Weiss

    > it is impressive that UNIX booted successfully without tripping over a
    > boundary.

Well, V6 is (or can be configured to be) extraordinarily small, so I'm not
surprised it booted OK without going over the 0170000 mark.

I have this persistent memory that the -11/40 in the CSR group at MIT had only
3 banks of MM-L (@16KB each) when I first got there! Which is plausible; the
smallest V6 config would have about 22KB of core text, and about 2KB of
initialized data. If you cut all the parameters to the bone (minimal number of
disk buffers, etc) you could probably get away with say 6KB of un-initialized
data. That would leave you 18KB for user programs on such a system, a bit less
than their recommendation of 24KB minimum for users, but probably minimally

We quickly added more memory, I'm sure, but I don't now remember how/what!
Later on it was converted to an -11/45, and then we got an Able ENABLE, but
that would have been a couple of years later.


More information about the cctalk mailing list