> On Feb 4, 2019, at 9:13 AM, Jay Jaeger <cu...@charter.net> wrote:
>
> If he hasn't already, if Fritz has more than one memory board, he might
> try swapping them to see if that changes anything.
I only have an 128kw MS11-L here to work with, unfortunately. Its been through
a bunch of recent troubleshooting (tracking down and replacing failed DRAMs).
I *think* its pretty solid at this point (also passing some of the hairier DEC
diagnostics) but...
I'd be happy to try out a different memory board if anybody was interested in
sending out a loaner? (I'm in the SF Bay area).
> The issue I'd see with the MMU swapout idea would be finding one that
> would be ECO-compatible with the rest of the processor.
Yes; per previous email.
> Other things I might be tempted to try in order to coax more information
> out of the situation:
>
> 1. Run the DEC system exerciser, if that has not already been done.
Done; passes consistently.
> 2. Make a copy of ls, and see if the copy also fails
> (different location on disk would mess with timing just a bit).
Also done; the copy appears to behave identically to the original.
> 3. Use SimH to build a pack image with an instance of ls that is not
> pure text (no -n or -i flag)
> 4. Use SimH to build an ls that does/does not start the data segment
> for ls at 0 (has / does not have the -i flag) [I have not looked to
> see how ls would normally be built.]
These may yet be interesting experiments.
> 5. Use SimH to gen a pack image with a kernel that is a not split I/D
The image I'm using is a /40-compatible one, built from the distro tape, the
one that you get before going on to rebuild for /45. So, as Noel has reminded
me, no split I/D. But we could try the opposite experiment (build a pack
customized for /45) and see if that's different?
The pain with that is that it takes me almost three hours to image a pack with
PDP11GUI over my DL11, and I have a very limited set of packs with which to
work (others on this list have graciously offered to help there; I need to send
y'all some shipping boxes!)
cheers,
--FritzM.
