Logic Unit Self-test and devices other than disk drives

Robert Elliott relliott at hobbit.eng.hou.compaq.com
Thu Jul 29 07:44:04 PDT 1999

* From the T10 Reflector (t10 at t10.org), posted by:
* relliott at hobbit.eng.hou.compaq.com (Robert Elliott)
Mark Evans' T10/99-179 proposal describes a logical unit self-test.  
It is intended to be usable by all device types, not just disk drives.

The self-tests can run in foreground or background mode.  In 
background mode, the self-test is aborted if certain commands are run 
during which the self-test cannot continue.  For SBC devices, these 
commands were determined to need this priority:
    WRITE BUFFER (Download microcode)

We need to document all the other device types.  For SSC Sequential 
Access Devices, for example, most of the commands should probably 
terminate a self-test.  A tape drive probably cannot be scanning 
the tape media the same time it is trying to write application data.  
An initial table is:

    abort = abort the self-test
    continue = continue the self-test

        Unique SSC Sequential Access Device Commands
    abort    ERASE
    abort    FORMAT MEDIUM
    abort    LOAD UNLOAD
    abort    LOCATE
    abort    READ
    continue READ BLOCK LIMITS
    abort    READ POSITION
    abort    READ REVERSE
    abort    REWIND
    abort    SPACE
    abort    VERIFY
    abort    WRITE
    abort    WRITE FILEMARKS

Any agreement or disagreement with this list?

For other device types, which commands should be listed?  The device 
standards listed in SPC-2 are:
    SBC    Direct Access Device
    SBC    Write Once Read Multiple Device
    SBC    Optical Memory Device
    SSC    Sequential Access Device
    SSC    Printer Device
    SPC-2  Processor Devices
    MMC-2  C/DVD Device
    SMC    Media Changer Device
    SCC    Storage Array Device
    RBC    Simplified Direct-Access Device
    OCRW   Optical Card Reader/Writer Device
    SES    Enclosure Services
    SCSI-2 Scanner
    SCSI-2 Communication
    (plus generic SPC-2 commands used by multiple device types)

Rob Elliott      UNIX mailto:relliott at hobbit.eng.hou.compaq.com    
Houston, TX        PC mailto:Robert.Elliott at compaq.com
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