Tape Alert Log Page and the PC field

Doug.C.Pirie at seagate.com Doug.C.Pirie at seagate.com
Mon Oct 21 12:52:01 PDT 2002


* From the T10 Reflector (t10 at t10.org), posted by:
* Doug.C.Pirie at seagate.com
*
I've seen applications that set byte 2 to a value of 0x2E and other
applications that have set byte 2 to 0x6E and so on.
I would suggest simply enabling your firmware to ignore the PC bits for
this page and then just return your Tape Alert data.
Since the TapeAlert page does not really have the concept of thresholds and
the only flags of interest to an application are the flags that are set I
would say that it is to much work for no gain to scratch your head trying
to figure out how to fit this page into a classic SCSI response.

Cheers,
Doug Pirie
Staff Applications Engineer
Seagate Removable Storage Solutions



----- Forwarded by Doug C Pirie/Seagate on 10/21/2002 12:41 PM -----
                                                                                              
                    "Kevin D                                                                  
                    Butt"                To:     t10 at t10.org                                  
                    <kdbutt at us.ib        cc:                                                  
                    m.com>               Subject:     Tape Alert Log Page and the PC field    
                    Sent by:                                                                  
                    owner-t10 at t10                                                             
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                    10/18/2002                                                                
                    04:08 PM                                                                  
                                                                                              
                                                                                              




* From the T10 Reflector (t10 at t10.org), posted by:
* "Kevin D Butt" <kdbutt at us.ibm.com>
*
I have a question about how the PC field is used in the industry in
relation to the Tape Alert flags (log page 0x2E).

A PC field of 10b is supposed to return the "default threshold values" of a
log page.

In the TapeAlert log page all 64 parameters are to be returned regardless
of whether or not they are supported.

I have been informed that in the industry, application clients use a
default threshold value of zero to indicate that a parameter is not
supported.  Is this true?

What is implied by the standards regarding the default threshold value when
a parameter is not supported.  Especially in the case of the Tape Alert
page?

Thanks,

Kevin D. Butt
Fibre Channel & SCSI Architect
IBM Tape Microcode,
6TYA, 9000 S. Rita Rd., Tucson, AZ  85744
Tie-line 321; Office: 520-799-5280, Lab: 799-2869, Fax: 799-4138, Email:
kdbutt at us.ibm.com


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