Re: [Gnu-arch-users] Re: arch with 'special files'

[Andrew Suffield]

On Wed, Apr 06, 2005 at 08:20:15AM +0200, Jan Hudec wrote:
> On Tue, Apr 05, 2005 at 18:17:05 +0100, Andrew Suffield wrote:
> > On Tue, Apr 05, 2005 at 03:34:25PM +0200, Jan Hudec wrote:
> > > > Inexact patching for jpeg images anyone? Or for (ugh!) XML RSS 
> > > > files[1]? Or...
> > > 
> > > I believe there is some kind of xml-diff, that compares the trees, not
> > > the text ;-). One such is built into openoffice...
> > 
> > Yes, but there's no corresponding patch tool, nor can there be (any
> > more than there can for xdelta), since XML is semantically null and
> > syntactically useless.
> 
> Even if there is a problem with generic XML, because it may have
> arbitrary semantics, it is certainly possible to have a patch tool for
> formats built on XML that do have specific semantics, eg. the OpenOffice
> documents.

Which would be a patch tool for openoffice, and be almost entirely
unrelated to XML. Anyway, it still doesn't exist.

> > > And even if it's not inexact patching, instead of two versions, you can
> > > store one version and a difference. And knowing the nature of the data
> > > can make this more efficient.
> > 
> > Delta compression is a fairly trivial storage optimisation that's not
> > particularly interesting. The archive isn't your problem for storage
> > anyway; it is the smallest thing in arch.
> 
> If the archive stores mostly Word documents, it certainly does make
> a difference.

Still premature optimisation. There are far larger things to worry
about than archives.

-- 
  .''`.  ** Debian GNU/Linux ** | Andrew Suffield
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