At Tue, 27 Oct 2009 23:02:00 +0100, Michal Suchanek
<hramrach%centrum.cz@localhost> wrote:
Subject: Re: git copies of cvs modules available
>
> 2009/10/14 Rhialto <rhialto%falu.nl@localhost>:
> > Yes, but the $Id$ that it supports is a hash value which is absolutely
> > meaningless to a human reader.
>
> Not that the CVS version is much more meaningful.
Note the key phrase here is "human reader".
A CVS identifier number not really truly meaningful in a direct sense of
course, but it is easily recognisable, and an average human reader can
easily (i.e. on a glance) compare RCS/CVS/SCCS style version identifiers
without any real effort whatsoever.
That's just not possible with a long hash string.
> When the file "escapes from" a VCS the version number is meaningless.
Well, "meaningless" outside the VCS only in the most strict sense.
In day-to-day reality the simple-form RCS/CVS/SCCS version identifiers
can still work without effort for the _human_ reader when one is dealing
with RCS/CVS/SCCS-style central (authoritative) repositories.
Key here though is of course that with a central authoritative
repository you don't need a VCS "context" in which to compare the
simple-form RCS/CVS/SCCS style version identifiers. They are easy to
compare in any context, even without any access to the repository,
because for a given file they all originate from the same source.
Of course once it gets down to the assignment of real meaning to the
identifier, i.e. the kind of meaning I think you were actually talking
about, then you do effectively need the repository, especially with CVS,
because any branch numbers are meaningful only with the context of one
file and so you need the related tag identifiers to compare them with
any other files. However this use is far more rare in my experience.
Most commonly, especially outside the direct context of the VCS, humans
usually just want to see if the IDs are the same or not, perhaps with
some hint as to their relationship in time if they're not. This works
even if you don't have the entire original source file to look at,
eg. when you compare the output of "what foo.o", etc.
--
Greg A. Woods
Planix, Inc.
<woods%planix.com@localhost> +1 416 218 0099 http://www.planix.com/
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