SAM-3 proposal: ... Sense Data sizes
LAVARRE at iomega.com
Mon Oct 28 08:19:36 PST 2002
* From the T10 Reflector (t10 at t10.org), posted by:
* "Pat LaVarre" <LAVARRE at iomega.com>
Can you easily elaborate?
In a place like:
the redundancy between .SenseInfoLength and chars[SenseInfoOffset + 7] exists in part because the host controls how in/accurate the .SenseInfoLength is and the target controls how in/accurate the chars[SenseInfoOffset + 7] is.
Apps then compete over whom to trust most when.
Only recently did I learn, for example, that a zeroed additionalLength in op x03 RequestSense data meant (xE - (7 + 1)) for the simulated Cd drives of a Connectix Virtual PC, until this year or so. AFAIK, Microsoft is still shipping zeroed additionalLength in op x12 Inquiry data (meaning x24 - (4 + 1)).
Given that such inconsistencies exist in some places, I'm curious to understand why we would not want to provide a way to forward them faithfully.
Curiously yours in truly breathtaking ignorance, Pat LaVarre
From: Ralph Weber [mailto:ralphoweber at compuserve.com]
Sent: Tue 10/22/2002 3:04 PM
To: t10 at t10.org
Cc: Elliott, Robert (Server Storage)
Subject: Re: SAM-3 proposal: ... Data-In and Sense Data sizes
1) There is no need for a Sense Data Size parameter because
the Sense Data format is self-defining with respect to
the number of sense data bytes present (see the ADDITIONAL
SENSE LENGTH field at fixed position byte 7 of the
Descriptor Sense Data Format). Adding a Sense Data Size
parameter only introduces new forms of inconsistent
(so might say erroneous) responses targets can generate.
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