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

jgeldman jgeldman at lexar.com
Thu Jan 3 09:20:34 PST 2008


* From the T10 Reflector (t10 at t10.org), posted by:
* "jgeldman" <jgeldman at lexar.com>
*
I believe there are two issues. The gramatical issue is the repeated  "should
be" phrase. 
The technical issue is that current sentences are misleading or
contradictory. The structure provides "at least" language for allocation
length if the EVPD bit is set or clear. However, zero is also a valid
allocation length as stated in the allocaton length
definition. While no useful INQUIRY information passes with a zero allocation
length, some USB systems use this to test if the command path is functional. 
So, one part of of the fix is to remove a repeated phrase and the other parts
explicitly document the possibility of zero for allocation length.
John Geldman
-----Original Message-----
From: "Ralph Weber" <roweber at IEEE.org>
To: "T10 at t10.org" <T10 at t10.org>
Sent: 1/2/2008 7:51 PM
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,
> ... The only possible clarification I can see is to explain
> a touch more about the reason for the five and four. ...
This of course assumes that some *reason* other than
"because the standard says so" is needed. :-)
All the best,
.Ralph
Mark Evans wrote:
> * From the T10 Reflector (t10 at t10.org), posted by:
> * "Mark Evans" <Mark.Evans at wdc.com>
> *
> Hi Pat,
>
> I'm not sure what you're trying to fix.  The only possible clarification I
> can see is to explain a touch more about the reason for the five and four.
> This could be done by adding a few words the paragraph you mention in 6.4.1
> INQUIRY command introduction as follows:
>
> The ALLOCATION LENGTH field is defined in 4.3.4.6.  If EVPD is set to zero,
> then the allocation length should be at least five so that the ADDITIONAL
> LENGTH field (i.e., byte 4 in the standard INQUIRY data) is returned
> providing the application client with the length of the data available (see
> 6.4.2).  If EVPD is set to one, then the allocation length should be should
> be at least four so that the PAGE LENGTH field (i.e., byte 3 or bytes 2 and
> 3 in a vital product data page) is returned providing the application
client
> with the length of the data in the specified VPD page (see 7.6).
>
> The cross references are already in the paragraph, but I guess a few more
> words wouldn't hurt.	Am I missing the issue that you're trying to resolve?
> Please let me know.
>
> Regards,
>
> Mark Evans
> Western Digital Corporation
> 5863 Rue Ferrari
> San Jose,  CA  95138
> Email: mark.evans at wdc.com
> Office: 408.363.5257
>
> -----Original Message-----
> From: owner-t10 at t10.org [mailto:owner-t10 at t10.org] On Behalf Of
> plavarre at lexar.com
> Sent: Wednesday, January 02, 2008 1:15 PM
> 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:
> * <plavarre at lexar.com>
> *
> Here's one specific way we could correct the Spc4r11.pdf 6.4 Inquiry
> English:
>
>
> """The ALLOCATION LENGTH field is defined in 4.3.4.6. [+ The allocation
> length should be zero else at least four or five.] If EVPD is set to
> zero, the allocation length should be at least five, so that the
> ADDITIONAL LENGTH field in the parameter data (see 6.4.2) is returned.
> If EVPD is set to one, the allocation length should be [- should be] at
> least four, so that the PAGE LENGTH field in the parameter data (see
> 7.6) is returned."""
>
>
> Like it?
>
>
> The [+] change notation indicates text I think we should add. The [-]
> change notation indicates text I think we should subtract. The
> """quotes""" enclose the wrong I see in our 14 May 2007 Spc4r11.
>
>
> Right way to move forward?
>
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