[Gnu-arch-users] Re: Re: [arch-users] advanced usage advice: the prism technique (fwd)

[Stig Brautaset]

On Sep 27 2003, Andrea wrote:
> > On the other hand, if you want to share project trees, which are
> > essentially unrelated in terms of arch, it's probably better to use an
> > external tool to hard-link files with identical content.  I have some
> 
> this tool already exists and it's attached (it was in a very very old
> package called perforate that I still use sometime in source form)
> careful, it destroys all the permissions so don't run it on /dev ;)
> 
>       finddup | nodup
> 
> they're small enough that I attached it.
> 
> Yes, that would save the duplication of space, but it would be slow (it
> sure can be improved in performance though) and it would still not
> address the speed of a 'get' of a pure tree.
> 
> Besides the space argument, one of the main properties of cp -la is that
> it takes nothing, unlike a cp -a or a tar xzf of a 500m payload similar
> to the 2.6 kernel.
> 
> > ideas for speeding up such a tool by caching (in fact I've recently
> > written something quite similar for my maildir folders).  This would
> > still result in full-tree copies if you use certain merging methods
> > (probably just "update"), but otherwise, it should come pretty close to
> > what you want.
> > 
> > Or am I missing something?
> 
> I don't think you're missing anything.

Revision libraries already consist of hardcoded files to save space. How
about adding an argument to `tla get' so that it would hardlink instead
of copying files from the revision library (if possible)? It escapes my
memory whether revision libraries now can work like cacherev, or if they
require sequential adding of revisions from base-0, aka the `magic
cache'.

Does that sound feasible? 

Stig

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