[sugar] Ideas for Journal: How epiphany browser manages bookmarks just with tags

[C. Scott Ananian]

On Sat, Sep 20, 2008 at 1:41 AM, Albert Cahalan <acahalan at gmail.com> wrote:
> The case of b/a being distinct from a/b is necessary. You may call
> it a necessary evil, but in any case is is necessary.

Surprisingly, it's not:
http://wiki.laptop.org/go/Experiments_with_unordered_paths

I still think it's worth supporting as an edge case, but from my
actual experiments, it seems that path ordering is almost never
actually necessary (!).

> For the journal to be truly usable, it needs to support pretty much
> all that we ask of a filesystem. You'll know you're doing OK when
> you can build joyride out of the journal. (git works, gcc works, etc.)

This is a good test case.  I'll confirm it, but I believe that this
should actually work with unordered paths.  The trickiness comes wrt
to security in a multiuser system; Michael has been thinking hard
about that.  (I prefer just to punt it for the moment.)

> Give priority to tags (and anti-tags) which split the set of
> files most evenly. This greatly reduces search time; it is
> equivalent to balancing a binary tree.

It turns out that only about 3 tags are needed to find any directory
among the 900,000 files in my home directory (I'm working on getting
better statistics, sorry).  So the opposite criterion might be more
important: give priority to tags which 'most narrow' the search --
that is, they match the *fewest* things!  Once you've entered two
search terms, the exact thing you are looking for ought to be in that
list; you don't want to be distracted by terms held in common by lots
of files which don't appreciably narrow your search.

I hope to implement experiments (as described in the wiki page cited
above) to start getting real life experience with these tradeoffs.
  --scott

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