SSC-4: Handling logical object counts greater than 4-bytes

Kevin D Butt kdbutt at
Thu Sep 10 10:49:25 PDT 2009

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I believe that we should add as one of the items for SSC-4 how to safely 
allow a greater number of logical objects to be stored on medium than can 
be represented by a 4-byte field. 
Today we have the Locate (10) and the Locate (16) where one uses a 4-byte 
field and the other uses an 8-byte field.
However, if there are greater than 2^4 logical objects the Locate(10) 
cannot represent that.	SSC-4 should clearly address what happens in this 
case.  There should be a model section where this issue is discussed and 
the method for resolving it.  This may be contained in responses to 
specific commands or there may need to be a more elaborate method.  I 
think to be safe a more elaborate method will be needed.
I plan to ask the groups opinion about the need to add this to the list of 
SSC-4 items.
Kevin D. Butt
SCSI & Fibre Channel Architect, Tape Firmware
MS 6TYA, 9000 S. Rita Rd., Tucson, AZ 85744
Tel: 520-799-5280
Fax: 520-799-2723 (T/L:321)
Email address: kdbutt at

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