SSC-3: mixing 4-byte vs. 8-byte commands inherent DI issue

Kevin D Butt kdbutt at us.ibm.com
Mon Feb 21 14:30:37 PST 2005


* From the T10 Reflector (t10 at t10.org), posted by:
* Kevin D Butt <kdbutt at us.ibm.com>
*
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I believe there is an inherent Data Integrity issue when mixing 4-byte
commands with 8-byte commands.  I do not think that SSC-3 addresses
this. 
As an example, if we locate to 4-byte max + n then do a Read Position
with the short form we get only n (if implementation wraps the value) or
some other incomplete LBA. 

Dave, 

Would you add this topic to SSC-3 WG agenda? 
How do we address this issue of intermixing 4-byte and 8-byte LBA value
commands in SSC-3? 

Thanks, 

Kevin D. Butt
Fibre Channel & SCSI Architect, IBM Tape Firmware, 
6TYA, 9000 S. Rita Rd., Tucson, AZ  85744
Tie-line 321; Office: 520-799-5280, Lab: 799-5751, Fax: 799-4138, Email:
kdbutt at us.ibm.com

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<br><font size=2 face="sans-serif">I believe there is an inherent Data
Integrity issue when mixing 4-byte commands with 8-byte commands. &nbsp;I
do not think that SSC-3 addresses this.</font>
<br><font size=2 face="sans-serif">As an example, if we locate to 4-byte
max + n then do a Read Position with the short form we get only n (if implementation
wraps the value) or some other incomplete LBA.</font>
<br>
<br><font size=2 face="sans-serif">Dave,</font>
<br>
<br><font size=2 face="sans-serif">Would you add this topic to SSC-3 WG
agenda?</font>
<br><font size=2 face="sans-serif">How do we address this issue of intermixing
4-byte and 8-byte LBA value commands in SSC-3?</font>
<br>
<br><font size=2 face="sans-serif">Thanks,</font>
<br><font size=2 face="sans-serif"><br>
Kevin D. Butt<br>
Fibre Channel &amp; SCSI Architect, IBM Tape Firmware, <br>
6TYA, 9000 S. Rita Rd., Tucson, AZ &nbsp;85744<br>
Tie-line 321; Office: 520-799-5280, Lab: 799-5751, Fax: 799-4138, Email:
kdbutt at us.ibm.com</font>
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