Combined initiator & target names in SAM-2

[Peter Johansson]

* From the T10 Reflector (t10 at t10.org), posted by:
* Peter Johansson <PJohansson at ACM.org>
*
At 08:19 PM 11/9/2001 +0000, Jim Hafner wrote:

[...] we have to ask ourselves what "device" is being named? Is it the 
physical device or the virtual device providing a specific function.  In
your "may be completely unaware of each other" statement, one can interpret 
that as being two independent devices that happen to share the same piece 
of hardware.  In that case, you have one target device with its name and 
one initiator device and its name.

On the other hand, suppose we allow for two different names (one that names 
the initiator function and one that names the target function).  Have we 
lost or gained anything?  The fact that it has two different names doesn't 
add any features over and above a picture of two virtual devices each with 
a unique name.  They will have to be managed separately in any case.  And 
how can you tell the difference between the two cases?

No matter how many times I read your examples, Jim, I find two names, one 
for initiator and one for target---whether it is a "device" or a "function" 
that is being named. By the way, what's the difference? (Rhetorical question)

>I think the sense of the WG was that there was no compelling reason to 
>have separate names [...]

Jim, since you and the WG seem ambivalent about two names vs. one, I claim 
a compelling reason to keep the names distinct. SBP has a 64-bit initiator 
name (or is it ID? I think they're one and the same in SBP) BUT a 88-bit 
target name. A node (similar, in some ways, to an FC port) is restricted to 
one initiator but may have many targets.

Since functionality of initiator and target is completely separable, why 
would one wish to model them in the same name space?


Regards,

Peter Johansson

Congruent Software, Inc.
98 Colorado Avenue
Berkeley, CA  94707

(510) 527-3926
(510) 527-3856 FAX

PJohansson at ACM.org

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