Re: [Gnu-arch-users] tagging-method explicit implementation

[Stephen J. Turnbull]

>>>>> "Bruce" == Bruce Stephens <address@hidden> writes:

    Bruce> it's not just that ext2 filesystems don't do small files
    Bruce> efficiently, it's that the implementation is just wrong.

Yeah, but this is also a problem of the filesystem.  Unix files have
no logical identity.  There's the inode, or physical file, which has
identity.  But lots of the ways in which we edit files (eg, Oh, damn!
well, OK, restart: "mv file~ file") change the physical identity,
although the logical identity is the same.  There's the name, but
that's real useful: "mv /boot/vmlinux /boot/arch.html".  Now,
arch.html is really a Linux kernel, right?  Note that in the first
case, the logical identity associates with the name, in the second,
with the inode.  There is a semantic difference between mv and rename,
but the Unix file system doesn't allow it to be expressed.

    Bruce> And the implementation goes right into the changeset and
    Bruce> archive storage.

There's no choice.  The identity of a file must go with the file.
Since the file system doesn't implement it, arch must.  Lose, lose,
yes.  But what are ya gonna do?

That's why tagline (y amigos) is attractive.  What we really want is a
virtual file system (ie, dentry) that allows attaching arbitrary
properties to a create a logical file identity, a "resource fork", as
MacOS has.  We don't have that, so put it in the file.

Note that in the Unix context the obvious robust way to manage a
resource fork is in an inode (contents are arbitrary, remember---in
XEmacs, we'd like to put our portable dumpfile, typically ~2MB, in the
resource fork).  Thinking that way, Tom's .arch-ids implementation is
not at all space inefficient!

    Bruce> That's what'll make it so awkward to change, I fear.

Amen, Brother Bruce!

But fear not, Brother.  Daniel Webster beat his Devil, and Tom Lord
will beat this one.  ;-)

    Bruce> if everything just used an inventory (directly or
    Bruce> indirectly), then the tagging method would be almost
    Bruce> entirely a user-interface preference.

But "inventory" implies "audit".  Go to any company or school.  Every
desk, every personal computer, in really anal places even the stapler
and cutting board will have an inventory number stickered or stenciled
to it.

I think that the only mistake Tom made was to allow human-readable
inventory tags.  That leads immediately to issues of "is whitespace
significant?" etc.  (Worse, comment delimiters---but only the trailing
ones!---are significant.  Oops!)  All the rest of the warts were
unavoidable, they came with the frog.

-- 
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