SSC-2: Comments

Kevin D Butt kdbutt at
Fri Jun 22 19:07:46 PDT 2001

* From the T10 Reflector (t10 at, posted by:
* "Kevin D Butt" <kdbutt at>
I have a few comments, questions, and/or suggestions for SSC-2 (T10/1434-D
Revision 03) Dated 29 April 2001.

On page 7, first paragraph, second sentence:
  "These words and terms are defined either in    or in the text where they
first appear."  This sentence needs corrected.

On page 12, 5.1.18 overlength:  THe ...  Typo.
                       5.1.19 partition:  ... last word is amnner, should
be manner. Typo.
                       5.1.20 prinicipal density code: ... forsupported ...
Typo, should be two words.

On page 32, Table 10 - Explicit address command set indicates that INQ is
optional.  If the explicit command set is being used
for that LUN then the INQ command may not be available.  Does this make

On page 34, 5.3.1 ERASE(16):  In paragraph 3 the IMMED and LONG bit are
referenced, but Table 11 does not indicate their position
in the command.

On page 35, 5.3.2 LOCATE(16):  Paragraph 1, sentence 2 is a fragment
without a complete thought.

On page 37, 5.3.4 READ REVERSE(16):  There are two periods at the end of
the paragraph.

On page 41, 5.3.7 WRITE(16):  Pagagraph below Table 18 references the
WR_APP bit which is not defined in the table.

On page 42, 5.3.8 WRITE FILEMARKS(16):  Fourth sentence in paragraph below
Table 19 references the WRITE(16) command.
Shouldn't this be the WRITE FILEMARK(16) command?

On page 44, Table 20:  The WRITE(6) command Type is 'W' instead of 'M'.

On page 48, 5.4.3 LOAD UNLOAD:  The paragraph describing EOT bit raises the
question, "If the medium must be unthreaded and can't
do so with the position at EOT, does this illicit a check condition, or
does this bit get ignored?"

On page 50, 5.4.4 LOCATE(10):  In the paragraph describing the LOGICAL
BLOCK ADDRESS the second sentence begins, "An otherwise valid LOCATE ...".
This seems to imply that there is a condition described that might be
invalid in some other case, but I don't see that case described.  Am I
missing something?

On page 50, 5.4.5 READ(6): The fourth paragraph describes the FIXED bit.
Shouldn't the description of a "... FIXED bit of zero shall transfer the
requested transfer length in bytes to the application client." say "...
FIXED bit of zero shall transfer up to the requested transfer length in
bytes to the application client." to indicate that less data may actually
be transfered?

On page 54, 5.4.7 READ POSITION:  The second paragraph after Table 30 -
READ POSITION service action codes.  "For service action codes of 08h and
higher, the PARAMETER LENGTH field ..."  Since all the service action codes
higher than 08h are illegal shouldn't the "... and higher ..." be removed?

On page 55, 5.4.7 READ POSITION:  The second sentence in the paragraph
describing LAST BLOCK LOCATION field is essentially a repeat of the first

On page 57, 5.4.7 READ POSITION:  Below Table 32 the TCLP bit is
referenced, but none of the tables show the TCLP bit.  It needs to be
defined somewhere.

On page 60, 5.4.7 READ POSITION:  The pragraph describing the ADDITIONAL
LENGTH field is describing the field called PARAMETER LENGTH in Table 33.
I suspect that Table 33 should be modified to say ADDITIONAL LENGTH.

In response to Editors Note 11:  I believe that it is desirable to have it
the way written, i.e. not modify the ADDITIONAL LENGTH field when
truncation occurs.

On page 65, 5.4.10 REPORT DENSITY:  In the paragraph describing the DEFLT
bit the SECONDARY DENSITY CODe needs the final e in the same font as the
rest of the word.

On page 65, 5.4.10 REPORT DENSITY:  In the BITS PER MM and MEDIA WIDTH
description paragraphs the value 0,5 should be 0.5 with a period instead of
a comma.

On page 66, 5.4.10 REPORT DENSITY:  In the paragraph describing the DENSITY
NAME the last sentence is confusing.  Perhaps a better wording would be,
"Assigning organizations shall be responsible for preventing the use of one
density name for multiple different densities and/or formats."

On page 68, 5.4.13 SPACE(6):  If the fourth sentence were moved prior tot
he third sentence it would be easier to follow.  i.e. Move "Prior to
performing the space operation, except as stated in the descriptioin of the
count field, the logical unit shall ensure that all buffered data,
filemarks, and setmarks have been transferred to the medium." to before the
sentence about the CHECK CONDITION.  As written the sentence about the
INFORMATION field seems to hang and make you look in the CDB for an

On page 69, 5.4.13 SPACE(6): In the paragraph after Table 42 the second
sentence has a repeated word "...A positive value N in hte COUNT field
field ...".

On page 71, 5.4.14 SPACE(16):  This command is an Explicit Address Model
command but is being described in the Implicit Address Model section.
Shouldn't it be moved to the correct section (and then reword so as to not
use the SPACE(6) command as reference to how it operates)?

On page 72, 5.4.14 SPACE(16):  The paragraph above Editors Note 13.  It
would be nice to add a note indicating that the reason for locating to the
LBA prior to spacing instead of just calculating the ending LBA, is so that
the SPACE behaves correctly when filemarks or setmarks are between the LBA
and the anticipated ending LBA of the SPACE.

On page 79,  The sentence below Table 51 states that a value of
one in the VALUE OF FLAG field indicates the flag is set.  Does this imply
that any other value including nonzero values indicate that its not set?

On page 80,  The indented portion of the paragraph describing the
MODE SENSE is very confusing.  It needs to be reorganized, especcially
paragraph C) subparagraphs a) and b).  I'm not sure I could figure out what
is meant by these paragraphs.

On page 81,  Should Table 56 be sorted by Page Code instead of

On page 82,  What is the difference between the DCE bit and the
DCC bit?  From the descriptions I can't tell what the behavioral differenc
of the drive will be.

On page 83,  In the paragraph following Table 58, there is a
duplicate word "...additional sense code qualifier qualifier..."

On page 93,  Table 65  PAGE CODE (11h, 13h, 14h) should be (12h,
13h, 14h).

On page 97, Table 68 Description of VAlue -01h to -40h the last
line has "...thetrue..." which needs a space and "... ocurs..." which
should be occurs.

Kevin D. Butt
IBM Tape Products
SCSI and Fibre Channel Microcode Development
65U/9032-2, 9000 S. Rita Rd.
Tucson, AZ  85744
Phone:  (520)799-5280, Tie-line 321-5280
Fax:  (520)799-4062
Email:  kdbutt at

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