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 useable. 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. Noel