Question about use of IEEE COMPANY ID in 11-322r2

Gerry Houlder gerry.houlder at seagate.com
Mon Oct 8 11:37:14 PDT 2012


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I have noted that 11-322r2 (Device crash dump) has a 32 bit field in the
returned data for IEEE COMPANY ID. I'm sure this is because the SATA
equivalent has a 4 byte field for this also. However, the IEEE Company ID
is a 24 bit value.
Neither the SATA version or the T10 version of the crash dump feature has
any guideline about how the 24 bit value is aligned within the 32 bit
field. There is also the issue of SATA being little endian and SCSI is big
endian. This could lead to interpretation problems when comparing crash
dump information from a SATA drive with crash dump information from a SCSI
drive that are from the same manufacturer (and should have the same company
ID value).
I suggest that the 4 byte value should be changed to a 3 byte value plus a
reserved byte. This would take care of how the 24 bit field is aligned. We
should also discuss whether we need to require the bytes to be always
little endian or always big endian regardless of whether the data is from a
SATA or SCSI drive.



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