SPC Inquiry for Quad-Aligned Zero -- deprecated since SPC-4 maybe

Mark Evans Mark.Evans at wdc.com
Thu Jan 3 12:10:56 PST 2008


* From the T10 Reflector (t10 at t10.org), posted by:
* "Mark Evans" <Mark.Evans at wdc.com>
*
Hi Ralph,
Don't ask me.  I was just trying to put in words where I thought Pat was
going.	Upon further review, I think that the play stands as called in the
standard.
Please feel free to call or send an email to me if you have any questions or
comments about this stuff.
Regards,
Mark Evans
Western Digital Corporation
5863 Rue Ferrari
San Jose, CA 95138
Email: mark.evans at wdc.com
Office: 408.363.5257
Fax: 408.363.5139
-----Original Message-----
From: owner-t10 at t10.org [mailto:owner-t10 at t10.org] On Behalf Of Ralph Weber
Sent: Thursday, January 03, 2008 9:32 AM
To: T10 at t10.org
Subject: Re: SPC Inquiry for Quad-Aligned Zero -- deprecated since SPC-4
maybe
* From the T10 Reflector (t10 at t10.org), posted by:
* Ralph Weber <roweber at ieee.org>
*
Mark,
What is wrong with TEST UNIT READY as a way to validate Command Out and
Status In processing?
Curious in Dallas,
.Ralph
Mark Evans wrote:
> * From the T10 Reflector (t10 at t10.org), posted by:
> * "Mark Evans" <Mark.Evans at wdc.com>
> *
> Hi Ralph,
>
> Now what I think Pat is trying to do is to highlight that setting 
> ALLOCATION LENGTH to zero in an INQUIRY command is allowed, and that 
> this setting may be used as, "...a way of asking to test Command Out 
> and Status In without asking to test Data...".  However, I think this 
> is covered.  Why the value in the ALLOCATION LENGTH should be set to 
> five or four is already explained by the cross references in 6.4.1 
> INQUIRY command introduction, albeit not as clearly as my suggested
wording, but definitely more succinctly.  Wow.
> Three "ly" adverbs in one sentence -- ha!
>
> The qualification for the five or four in the ALLOCATION LENGTH field 
> in an INQUIRY command as defined in 6.4.1 is only a "should".  Based 
> on that text, zero is allowed as a value in the field for whatever 
> reason.  In addition, the second paragraph in 4.3.4.6 Allocation 
> length reads, "An allocation length of zero specifies that no data 
> shall be transferred.  This condition shall not be considered as an 
> error."  So, 6.4.1 implicitly permits zero as an allowed value for an 
> INQUIRY command, and 4.3.4.6 explicity allows a value of zero in an
ALLOCATION LENGTH field for any command.
>
> I think that there are many words that could be added to further 
> explain the setting of the ALLOCATION LENGTH field in an INQUIRY 
> command.  However, "the standard [already] says so."
>
> Pat, if you want some more words in SPC-4, I'd suggest submitting a 
> proposal to T10, but based on what is already in the standard, I think 
> you may have tough sledding.
>
> Regards,
>
> Mark Evans
> Western Digital Corporation
> 5863 Rue Ferrari
> San Jose,  CA  95138
> Email: mark.evans at wdc.com
> Office: 408.363.5257
> Fax: 408.363.5139
> Cell: 408.391.780
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