Question on Read-Write Error Recovery mode page PER operation

Kevin D Butt kdbutt at us.ibm.com
Mon Nov 10 08:32:23 PST 2008


Formatted message: <a href="r0811102_f.htm">HTML-formatted message</a>

Bill,
Did you mean to say "This interpretation is consistent..." or did you mean 
to say, "This interpretation is INconsistent..."  which is what it seems 
to me.
If PER is set to one, then you report RECOVERED ERROR on your temporary 
errors, but if PER is set to zero, then you do not report anything because 
your ERP worked.  That is how IBM tape drives have functioned for decades.
Thanks,
Kevin D. Butt
SCSI & Fibre Channel Architect, Tape Firmware
MS 6TYA, 9000 S. Rita Rd., Tucson, AZ 85744
Tel: 520-799-2869 / 520-799-5280
Fax: 520-799-2723 (T/L:321)
Email address: kdbutt at us.ibm.com
http://www-03.ibm.com/servers/storage/ 
From:
Bill.Martin at Emulex.Com
To:
<t10 at t10.org>
Cc:
<Narayan.Ayalasomayajula at Emulex.Com>
Date:
11/07/2008 05:29 PM
Subject:
Question on Read-Write Error Recovery mode page PER operation
In the description of PER in the Read-Write Error Recovery mode page, the 
following is stated:
A post error (PER) bit set to one specifies that if a recovered read error 
occurs during a command performing a read or write operation, then the 
device server shall terminate the command with CHECK CONDITION status with 
the sense key set to RECOVERED ERROR. A PER bit set to zero specifies that 
if a recovered read error occurs during a command performing a read or 
write operation, then the device server shall terminate the command with 
CHECK CONDITION status, and shall perform error recovery procedures within 
the limits established by the error recovery parameters. If the DTE bit is 
set to one, then the PER bit shall be set to one.
It seems that the first and second sentences require mostly the same thing 
as far as reporting a CHECK CONNDITION.  I think that the second sentence 
is missing a ?not? in the device server shall NOT terminate the command 
with CHECK CONDITION status, ?
This interpretation is consistent with the first two rows of table 128 
also, which state ?The device server shall not report recovered read 
errors. The device server shall terminate a command performing a read or 
write operation with CHECK CONDITION status before the transfer count is 
exhausted only if an unrecovered error is detected.?
Bill Martin
Emulex
Office of Technology
Industry Standards
916 772-3658
916 765-6875 (Cell)
bill.martin at emulex.com



More information about the T10 mailing list