Mode Pages implementaion

Mode Pages implementaion

[VaibhavNipunage]

Hi All,

I want some help in Mode Pages. Currently I am implementing mode pages. 

When initiator sends Mode Sense (0x1Ah) with requested page opcode (0x3F :
all pages), then at that time on target side, target got the Allocation
Length as 192. I dont know why it is getting 192 size. I read PC-3 doc,
according to that target should receive 256 (for MODE SENSE 6) or 65,536
(for MODE SENSE 10). I am confused why this is happening? 

Please help me.

Thanks in advance.
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Re: Mode Pages implementaion

[Matthew Wilcox]

On Fri, Apr 24, 2009 at 03:26:10AM -0700, VaibhavNipunage wrote:
> When initiator sends Mode Sense (0x1Ah) with requested page opcode (0x3F :
> all pages), then at that time on target side, target got the Allocation
> Length as 192. I dont know why it is getting 192 size. I read PC-3 doc,
> according to that target should receive 256 (for MODE SENSE 6) or 65,536
> (for MODE SENSE 10). I am confused why this is happening? 

Allocation Length is the amount of space the initiator has available
for the response.  It can be any length (including zero, which SPC4 is
very clear is not an error).  See section 4.3.5.6 Allocation length in
spc4r14 or 4.3.4.6 Allocation length in spc3r23.

-- 
Matthew Wilcox				Intel Open Source Technology Centre
"Bill, look, we understand that you're interested in selling us this
operating system, but compare it to ours.  We can't possibly take such
a retrograde step."

Re: Mode Pages implementaion

[Vaibhav Nipunage]

Thanks Matthew for you help.

I will go through the SPC-4 and read about it.

But I tried the same (above) thing and try to connect the target
through open iscsi initiator.In this case on target got 4 as a
allocation length (for page of 3f). So how to respond information of
all pages in those 4 bytes? or any thing wrong is happening? Correct
me if I am wrong.

Thanks once again.

On Fri, Apr 24, 2009 at 5:53 PM, Matthew Wilcox <matthew@wil.cx> wrote:
> On Fri, Apr 24, 2009 at 03:26:10AM -0700, VaibhavNipunage wrote:
>> When initiator sends Mode Sense (0x1Ah) with requested page opcode (0x3F :
>> all pages), then at that time on target side, target got the Allocation
>> Length as 192. I dont know why it is getting 192 size. I read PC-3 doc,
>> according to that target should receive 256 (for MODE SENSE 6) or 65,536
>> (for MODE SENSE 10). I am confused why this is happening?
>
> Allocation Length is the amount of space the initiator has available
> for the response.  It can be any length (including zero, which SPC4 is
> very clear is not an error).  See section 4.3.5.6 Allocation length in
> spc4r14 or 4.3.4.6 Allocation length in spc3r23.
>
> --
> Matthew Wilcox                          Intel Open Source Technology Centre
> "Bill, look, we understand that you're interested in selling us this
> operating system, but compare it to ours.  We can't possibly take such
> a retrograde step."
>



-- 
Vaibhav Nipunage
Systems Engineer

QualEx Systems Pvt. Ltd.
www.qualexsystems.com
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