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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] RE: iSCSI: padding on intermediate sequencesApparently FC had to make this restriction (see EMAIL from Robert Snively
[rsnively@brocade.com] dated 3/27). We should consider that as a basis for
discussion.
I have
quoted Bob below:
>Since there is no requirement by the SCSI
ULP to say anything about data until
>the SCSI Status has been presented, there is
no need to concern ourselves with
>device dependent burst boundaries. We
can make the boundaries convenient
>for the technology. In FCP, all bursts
were required to begin on a
>4-byte boundary, and all except the last to
end on a 4-byte boundary. This
>simplified DMA and segmentation/reassembly
mechanisms
>in all hardware paths. Looking at the
TCP/IP formats, I see a similar
>bias toward 4-byte structures, which implies
that the same rule would be
>a constructive addition to the
document.
>
>This simply prohibited the target from
asking for a number of intermediate
>bytes that was not a multiple of
4.
>
>The folks using odd byte block counts had to
manage the buffers in
>a manner appropriate to such
behaviors. Practically, I do not believe that
>there were many such devices, nor was this a
burden to any devices that did
>support such
behavior.
>
>Bob Eddy
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