At Bruce's request, I'm posting this to the list in
the hope someone can help confirm my hypothesis or
point me in the right direction.
I've got 4 WD1200JB-00FUA0's attached to a 3ware 7500
controller running FreeBSD. This means that
1) smartmontools doesn't work (since TWE apparently
isn't yet supported in FreeBSD), and
2) I can use the 3ware CLI to dump SMART data.
Online research indicates that the 1200JB historically
didn't support attribute 194 (0xC2), temperature.
However, doing a SMART dump using the 3ware CLI, I've
found the fields. They're as follows (in context, and
with linebreaks to separate the attributes):
C2 22 00 6F FD 27 00 00 00 00 00 00
C4 32 00 C8 C8 00 00 00 00 00 00 00
The interesting thing is that the C2 attribute's raw
data (0x27) appears to be the temperature in Celsius
(just a guess; I've loosely correlated warmup time to
increases in this field). The other data (0x6F)
appears to be 0x96 minus that data. This happens all
the time across all disks (output is from a perl
script I wrote that extracts that data from the 3ware
disk byte (in dec)
num 0 2
disk0: 113 37
disk1: 114 36
disk2: 119 31
disk3: 114 36
Notice that offset byte 0 (offset from the start of
meaningful data, or right past the 0x0022) is merely
(150-offset byte 2). In several hundred queries, I
have not seen an example where this equation does not
Some additional evidence supporting my theory that
temperature sensing on these drives is now possible:
the SpeedFan program
(http://www.almico.com/speedfan.php) claims to support
temperature reading on this revision of the 1200JB
(but not others?).
Can someone confirm that this revision of WD1200JBs
actually has temperature sensors, and that I'm reading
the data correctly?
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