More than an Identifier ...but... less than a Name

Gerry Houlder gerry.houlder at seagate.com
Thu Jan 20 14:16:51 PST 2011


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The discussion on this subject during the T10 meeting got better
understanding of the whole "point in time copy of stuff" concept by calling
it a snapshot. Snapshot seems like a perfectly good term.
On Thu, Jan 20, 2011 at 2:58 PM, Joe Breher <joe at lingua-data.com> wrote:
> * From the T10 Reflector (t10 at t10.org), posted by:
> * Joe Breher <joe at lingua-data.com>
> *
> Hmmm. This could make for an interesting philosophical discussion.
>
> In my mind, names are not long-lived so much as they are permanent. The
> name is a property of an object as long as that object is in existence.
> Further, names have the characteristic that, for the entire life of any
> given domain, the name uniquely identifies a given object - whether that
> object has not yet been instantiated, is currently in existence, or is no
> longer in existence. That name will never be reused within a given domain.
>
> Yes, I acknowledge that several things we refer to as 'names', may not be
> names per this definition, unless they are fully-qualified names. A true
> name may contain a time component. A good example of such would be a WWN as
> per the iSCSI IQN textual format.
>
> Identifiers, by contrast, only need be unique within a given domain at an
> instant in time. They are the 'handle-like-thing' by which we refer to any
> given object, within a given domain, at a given instant in time.
>
> Do we really need an intermediary term? Why is 'identifier' not the proper
> classifier for the characteristic employed in referring to a 'pile of
> point-in-time logical block copies'?
>
>
> On Jan 20, 2011, at 12:37 PM, Ralph Weber wrote:
>
> > * From the T10 Reflector (t10 at t10.org), posted by:
> > * Ralph Weber <roweber at ieee.org>
> > *
> > Here is the perfect kind of grist for the CAP-ites
> > to chew on.
> >
> > Today, SCSI has Identifier, which are short-lived numbers
> > that identify something (e.g., Command IDs, formerly Tags,
> > identify one command as the Q in an I_T_L_Q nexus).
> >
> > SCSI also has Names, which are long-lived constructs that
> > uniquely identify something (e.g., a logical unit name).
> >
> > What is the right term for something in the middle (neither
> > short- nor long-lived) that identifies something (e.g.,
> > the pile of point-in-time logical block copies in a
> > Copy Offload operation (such as was discussed in Irvine)?
> >
> > The current proposal says "token".
> >
> > If there are better ideas, please post them to this reflector.
> >
> > All the best,
> >
> > .Ralph
> >
> > P.S. Whatever gets chosen will be around for a long time.
> > *
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>
>
> *
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