4 Feb
2019
4 Feb
'19
9:34 a.m.
On Feb 4, 2019, at 9:13 AM, Jay Jaeger <cube1 at
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.