Jack Stone wrote:
Chris Snook wrote:
But what you're talking about *will* break userspace. If I do an ls in
a directory, and get pages upon pages of versions of just one file,
that's broken. If I tar up a directory and get a tarball that's
hundreds of times larger than it should be, that's broken. If you want
the files to be hidden from userspace applications that don't know about
your backup scheme, (and it sounds like you do) then use the existing
convention for hidden files, the prepended '.' This is the universal
sign for "don't mess with me unless you know what you're doing".
The idea was that if you did an ls you would get the latest version of
the file without the :revision_num. The only visible version would be
the latest version, i.e. the current system would not change. The idea
was that it would only show earlier versions if they were specifically
requested with a :revision_num suffix. In that case the
filesystem/kernel would need to recognise the suffix and return the
earlier version of the file.
The only userspace it would break is files with :num in their name, as I
haven't seen any files like that I don't think its too big a problem but
the way of specifiying revisions could be changed.
Jack
I have one right now:
$ ls /tmp/ksocket-csnook/kdeinit*
/tmp/ksocket-csnook/kdeinit__0 /tmp/ksocket-csnook/kdeinit-:0
Note, I did not pass any special arguments to ls to make it pull up that file.
You'd have to modify ls to make it do that. You'd also need to modify
everything else out there. There are decades of programs out there that would
behave differently with the interface you propose.
The more fundamental problem with your proposed interface is that it treats a
filesystem like an opaque server, instead of a transparent data structure. You
want files to be completely invisible to applications that don't know about it,
unless the user requests it. Unfortunately, it doesn't work that way.
Applications ask for a directory listing, and will open the requested file if
and only if the filename in question appears in that listing. If you want to
use this opaque server model, you'd be better served putting it in some parallel
file system (say, /backup) that won't interfere with naive applications
accessing the mundane data. Personally, I like your idea of putting the older
versions in the same directory hierarchy, but I think you'd have to use .foo
hidden directories to do it right.
-- Chris
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