PDP-11/45 RSTS/E boot problem

Update from last night: I did manage to build a bootable single-RK05 V6 unix image under SIMH, starting from the Ken Wellsch tape image. Yeah, it needs to be converted to SIMH tape format, as documented in various places on the web, including actually a gunkies page that I didn?t notice until later :-) Wrote to an actual pack (~3 hrs with PDP11GUI, ugh, really need that USB FIFO hack, picking up some tri-state buffers for it today on way to work.) Kernel boots on my actual hardware, but an ?ls? in single-user mode generates a ?Memory error -- core dumped.? So evidence is mounting that I really do have some sort of issue with my MS11-L. Tried a multi-user boot for kicks, and I?m actually able to ?ls? under that. But it croaked trying to run the C compiler. So I could work to extract the core file (and also to follow Paul?s instructions to extract a crash file from RSTS), but probably the best application of effort would be to do develop/run more diagnostics on the MS11-L and see if I can shake out any problems there? cheers, --FritzM.