>>>> putting good 4Mx36 sticks on either side of it will usually
>>> I.e. put the suspect SIMM in slot 1 and populate slots 0 and 2 with
>>> 4M devices?
>> Or 0 and 3, in which case you can try out two suspect sticks at the
>> same time, in 1 and 2.  [...] As long as both the lowest and highest
>> ones are good, the POST seems to be happy.
> Hmmm... another blivet in the FAQ?  IIRC, it claimed the sockets had
> to be filled "in order"...

That certainly is not the case with the one IPX I am in a position to
easily test with.  It has 24M, 2x4+1x16, and I put the 4 in 0 and 1,
the 16 in 3, and left 2 empty - and the POST found all 24M.  (Which
incidentally also knocks on the head the "largest devices in lowest
slots" theory for at least this one IPX.)

>> If you look at the addresses printed for the RAM regions when
>> diag-switch? is true, you'll see that the highest nonempty socket
>> appears to end something like 0x2000 before it actually does.
> I will try to recall checking this next time I have a monitor
> attached to a box...

This turns out to have been flaky memory on my part.  The diag-mode
printout shows the whole thing.  It's when it passes the memory regions
to the kernel that it snips out a fragment....

> As an aside, is there any dmesg(8) sort of way of getting at the prom
> monitor's signon banner?

Not AFAIK.

>> (I think diag-mode? true produces output on the serial port much
>> earlier than it produces anything on the framebuffer, which is
>> hardly surprising as the FORTH engine has to be up to initialize
>> many framebuffers.)
> This seems to be a flaw in the design.  IMHO, rom monitors should be
> able to operate in the absence of memory (!)

I could see a justification, perhaps, for a minimal mini-monitor that
could run just out of CPU registers (especially on the SPARC, which
typically has hundreds - though not all accessible at once, for a
mini-monitor which doesn't need to handle exceptions or interrupts it
could be faked).

/~\ The ASCII				der Mouse
\ / Ribbon Campaign
 X  Against HTML	       mouse@rodents.montreal.qc.ca
/ \ Email!	     7D C8 61 52 5D E7 2D 39  4E F1 31 3E E8 B3 27 4B