READ_DMA48 error interpretation

Chuck Swiger cswiger at
Thu Feb 8 01:30:55 UTC 2007

Richard Lynch wrote:
> [I've tried to snip away a lot of stuff, without losing any context...]
[ ...trimming away context good, people can go back and read the thread... ]

> I can touch the exposed front and back top (above IDE cable) and lay
> my finger along it.  It's "hot" but not like, "ouch hot" :-)

You're not seeing any reallocated sectors and you're not seeing UDMA errors 
(ie, in the cabling).  For lack of any better guesses, I'd gather that your 
drives are running above normal temps and aren't reading data perfectly, but 
are doing well enough that the built-in ECC is managing to deal with the issues.

> I don't think it's 100C+ hot, as that's boiling -- but perhaps the
> thermometer is somewhere inside or...

On a good day, the thermometers actually provide a real, calibrated, accurate 
result...but many drives don't even come close.

>> The output of smartctl -a for one or two of your drives would likely
>> be much more indicative.  I don't claim to be an expert in this at all,
>> but some of us might spot any obvious anomalies.
> I sure appreciate the time y'all are taking on this!
> I am definitely not a hardware guy, as you have probably already
> surmised. :-)

You should actually run "smartctl -t long /dev/ad0" and repeat for all of the 
devices, and then re-check the "smartctl -a" output.  Might be better not to 
run the self-tests all at once, come to think of it.


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