Read Attribute - Incorrect Medium Error?

Paul.A.Suhler at certance.com Paul.A.Suhler at certance.com
Mon Apr 25 11:28:25 PDT 2005


* From the T10 Reflector (t10 at t10.org), posted by:
* Paul.A.Suhler at certance.com
*

Hi, Kevin.

If the MAM isn't accessible, is it likely ever to be?  I would guess not,
making the sense key of MEDIUM ERROR correct.  (Do you have a counter
example?)

Instead, I'd like to suggest changing the beginning of the additional sense
code name to something other than 'LOGICAL UNIT NOT READY."  This is, of
course, ugly because 0410h is in the middle of a bunch of additional sense
codes that do begin that way.

If we change either the sense key or the numerical value of the ASC/Q, then
we would break existing implementations.

Thanks,

Paul Suhler
Firmware Engineer
Quantum Corporation
1650 Sunflower Avenue
Costa Mesa, California  92626
(714) 641-2485 (voice)
(714) 966-7328 (fax)



                                                                                                                                       
                      "Kevin D Butt"                                                                                                   
                      <kdbutt at us.ibm.co        To:       t10 at t10.org                                                                   
                      m>                       cc:                                                                                     
                      Sent by:                 Subject:  Read Attribute - Incorrect Medium Error?                                      
                      owner-t10 at t10.org                                                                                                
                                                                                                                                       
                                                                                                                                       
                      04/25/2005 09:35                                                                                                 
                      AM                                                                                                               
                                                                                                                                       
                                                                                                                                       





All,

In SPC-3r22a, clause 6.14.1 READ ATTRIBUTE command introduction the
following exists:
<<If the medium is present but the medium auxiliary memory is not
accessible, the READ ATTRIBUTE command
shall be terminated with CHECK CONDITION status, with the sense key set to
MEDIUM ERROR, and the
additional sense code set to LOGICAL UNIT NOT READY, AUXILIARY MEMORY NOT
ACCESSIBLE.>>

Why is it a MEDIUM ERROR when we have a LOGICAL UNIT NOT READY condition?
MEDIUM ERRORs are taken by applications to be nasty problems that cause the
medium to be called  bad.  In this case, it seems that the medium just
needs to be placed in a different position (e.g. Tape is in the drive but
not yet mounted.  There is no medium error, but the MAM is not accessible
until the medium is mounted.)

I think this is in error and needs to be changed to a NOT READY sense key.

What do you all think?

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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