Re: PLink availability/feature requests

From: Eric Armstrong (eric.armstrong@eng.sun.com)
Date: Wed Apr 25 2001 - 14:26:26 PDT


My expectation was that the combination of
  * username
  * system name
  * timestamp

is necessary for unqiue identification.

The use of system name was necessary to avoid overlapping
timestamps, since two systems *could* have different clocks,
and a person could easily create a node from two different
systems.

Unfortunately, that is a lot of overhead for every node.
I didn't see a better solution, at the time, but I'll
happily entertain a better idea!

Eugene Eric Kim wrote:
>
> On Mon, 23 Apr 2001, Eric Armstrong wrote:
>
> > 1) The ID should ideally be globally unique.
> > That requirement allows me to modify a document, while you
> > do likewise, and merge our additions with a minimum of
> > overlap problems. (The fact that we both created nodes in
> > the same place creates a decidable problem: Should your
> > change come before or after mine. But if we both create a
> > node with the same ID, the issue is realistically
> > undecidable: Who gets the original ID, who gets a different
> > ID, and what happens as a consequence of changing the ID
> > you *thought* you had created, if you are the loser.
>
> No two people should ever create a node with the same ID. You can get
> around this simply by attaching the user ID to the ID of every document.
> If two people are trying to merge changes to the same node, it'll
> necessarily be up to a human to resolve which addition gets merged. I'm
> not aware of any version control system that works otherwise.
>
> -Eugene
>
> --
> +=== Eugene Eric Kim ===== eekim@eekim.com ===== http://www.eekim.com/ ===+
> | "Writer's block is a fancy term made up by whiners so they |
> +===== can have an excuse to drink alcohol." --Steve Martin ===========+



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