Subject: Re: Isolating memory error
To: None <port-sparc@NetBSD.org>
From: der Mouse <mouse@Rodents.Montreal.QC.CA>
List: port-sparc
Date: 09/09/2003 14:13:31
>> On a 20, SIMMs appear 64MB (the max SIMM size) apart. Their base
>> addresses are multiples of 04000000. The address you cite,
>> 0x01e76b89c, is 7*0x04000000 + 0x276b89c. Thus, counting SIMMs from
>> 0, it is in SIMM number 7 (which is obviously a 64M SIMM, since it
>> contains an address above the 32M mark).
> Thanks for the tip on turning on diag-switch?. It says:
> Probing Memory Bank #0 64 Megabytes of DRAM
> Probing Memory Bank #1 64 Megabytes of DRAM
> Probing Memory Bank #2 Nothing there
> Probing Memory Bank #3 Nothing there
> Probing Memory Bank #4 Nothing there
> Probing Memory Bank #5 64 Megabytes of DRAM
> Probing Memory Bank #6 Nothing there
> Probing Memory Bank #7 32 Megabytes of DRAM
> Do you guys still think it's in bank #7 now, given that #7 contains a
> 32 Mbyte SIMM and not a 64 Mbyte SIMM, as you previously had
> surmised?
No. Now I don't feel at all confident of the analysis above.
It could be that the 64M stride I gave is wrong. But 128M would put it
in bank 3, which is even less plausible. And if SIMMs are addressed
256M apart, the address given is in SIMM 1 but at an offset well over
64M from the SIMM's base.
In my recent experience, which is with a 10 rather than a 20, I also
see "testing memory" lines that give base addresses and count down the
sizes. If you get anything of the sort (my 20 is not in a circumstance
where it can be casually power-cycled), that can give you the memory
area bases and sizes.
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