Re: ISCSI: need to fix handling of partial data transfers

[Paul Koning <ni1d@arrl.net>]

Excerpt of message (sent 18 March 2002) by Julian Satran:
> Device operation is not in the iSCSI domain.  You can find the information
> you need in SCSI.
> It comes complete with device type, capabilities, alignment required(if
> any), block sizes and much more (enough to fill many pages for every device
> class).  If you want the information you require just ask for it by SCSI
> means.
> A perusal of the SCSI standards for several classes of devices might help.

I have looked through SAM-2, the common commands standard, and the
block devices standard.  In SAM-2, I found the discussion I mentioned;
nothing else showed up that I could find.  I wasn't talking about
block sizes, device types, or stuff like that.

Indeed, device operation isn't part of iSCSI.  But I wasn't talking
about device operation.  The subject is moving data from and to the
devices, and that certainly is the job of iSCSI.  It's the job of
iSCSI to allow an initiator to talk successfully to a target.  If one
end has limits on how it can talk, it should therefore also be part of
iSCSI to communicate those limits to the other side.

I prefer to find out the limitations ahead of time, rather than to
bump into them and be told "surprise, you can't do that".  Most of the
time, iSCSI lets you know ahead of time.  Why else would we have login
parameters like Max PDU size?

	   paul