SES rev 8b Doc questions

Hamel, Mark Mark.W.Hamel at
Wed May 3 08:42:01 PDT 2000

* From the T10 Reflector (t10 at, posted by:
* "Hamel, Mark" <Mark.W.Hamel at>
Hi folks:

While reviewing the "SES, SCSI-3 Enclosure Services Command Set, (SES), REV
8b" document, there appeared to be some apparent inconsistencies on some
items that I would appreciate some input on, as well as some clarification
on other items:

1) In Annex A, Table A.2, pages 68 and 69, the PRODUCT REVISION LEVEL field
of the Primary sub-enclosure descriptor occupies bytes 44-47; this is a
4-byte field.  However, this same field for all of the other sub-enclosures
in the table is documented as an 8-byte field.  Further, the same field is
described in section 6.1.1 as a 4-byte field.  This seems inconsistent.  Is
there a specific reason why the fields are of different lengths?

2) In the description of the Element descriptor page in section 6.1.11,
Table 18 on page 32 shows the DESCRIPTOR LENGTH field to be arranged in
Little Endian order.  In other SCSI specifications, multiple byte fields are
arranged in Big Endian order. Is this a typo? If not, is there a specific
reason why this is in Little Endian order?

3) In section A.3, in the sixth paragraph on page 70 labeled TYPE DESCRIPTOR
HEADER:, the fourth sentence reads:  "All those elements defining SCSI
devices shall be listed before elements of other types, regardless of
sub-enclosure identification."  Does anyone recall why this rule was added??

It seems that an additional pass over the incoming data is needed to satisfy
this requirement.  

4) In section 6.1.1, in the seventh paragraph on page 17 labeled
SUB-ENCLOSURE IDENTIFIER:, a primary sub-enclosure is defined.  Does this
definition apply to sub-enclosure reporting as defined in Annex A?
Specifically, must the primary's sub-enclosure identifier be zero?  This may
create fail-over problems for the user of an SES device if the primary must
be sub-enclosure zero.  

I would appreciate anyone's comments on these. Thanks.

Best Regards:
Mark Hamel
Compaq Computer Corporation
Advanced Technology Group
Storage Products Division
Tel # (508) 841-2653
Fax # (508) 841-2556
e-mail: mark.w.hamel at

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