94-188r1 -- Proposed INQUIRY command enhancements

Gerry Houlder Gerry_Houlder at notes.seagate.com
Thu Oct 20 07:24:34 PDT 1994


This proposal keeps getting better and better, but I have suggestions for some
changes:
 
1) There isn't any wording that says what to do if the EVPD bit and CmdDT bit
are both set. This should be an illegal state. I suggest that these two bits be
made into a field that is described as follows:
 
     00 - Return standard Inquiry data
     01 - Return VPD page data (optional)
     10 - Return Command support data (optional)
     11 - Illegal.
 
This scheme provides clearer guidance on how to handle the '11' state. I used
the word "illegal" instead of "reserved" to show that this state gets rejected
with Illegal Request sense even if reserved fields aren't checked. If the
committee is ABSOLUTELY SURE that no one would think that a '11' value should
be ignored if we put "reserved" there, then I would agree.
 
2) I think the VSOp and StdOp bits should become a 2 bit field in similar
fashion, due to the sneaky addition of a special meaning to the '11' state of
these bits. Ralph seems to have them defined as follows:
 
     00 - Requested Op Code is not supported
     01 - Requested Op Code is supported as defined in SCSI Standard
     10 - Requested Op Code is supported in a vendor specific way
     11 - Command support data not yet available.
 
I think that changing these bits to a field like this adds greatly to
understanding the available functions.
 
3) There needs to be more description of the "ANSI approved version" field, at
least. What version of which documents? Should there be separate fields for
SPC, SBC documents (for block command devices)? The definition of the second
document needs to be dependent on the SCSI device type. It may not make sense
to use the same field here that is reported in Standard Inquiry data because
that data may not be useful enough. This area needs to be discussed at the next
working group meeting.
--
Gerry Houlder -- Gerry_Houlder at notes.seagate.com
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### OGATE Version 8 message trace and attachment information:
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### Org Date:    10-20-94 07:30:58 AM
### From:        Gerry Houlder at SEAGATE
### To:          scsi @ WichitaKS.NCR.COM @ internet
### Subject:     Re: 94-188r1 -- Proposed INQUIRY command enhancements
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