Re: [9fans] Installed Plan 9, now what?

[Geoff Collyer <geoff@collyer.net>]

I believe rsc and presotto mean to say `indirection', not
`redirection'.  To see the potential problem with just adding another
level of indirection everywhere, consider the evolution of Lunix's
filename space.

Originally people edited files, including in places like /etc,
directly.  Then people began to worry that if they changed those
files, their changes would get stomped on by the next OS upgrade from
their vendor.  In that world, checking changed files into RCS would
let one just check them out again after an upgrade; in our world, we
can just copy them out of the dump.  But instead, people created a
parallel file tree under /usr/local (or /local [a symlink] in places
where people got tired of typing "/usr/local" endlessly).  So
additions and changes in /usr/local were now thought to be safe
against upgrades.  But then some vendors caught on to /usr/local and
started shipping free-ish software pre-installed in /usr/local.  And
the gnu-ish folk decided that all non-vendors software should be
installed in /usr/local.  And some organisations wanted to share a
standard /usr/local across their machines, including suborganisations.
U of Toronto ended up with /csri/local, /cs/local, /ai/local and
probably others that I've forgotten; I think U of Waterloo took it
even farther (they've been much more ideological ☺).  So what's local,
and who owns it?  At various times, these owners have existed:

- AT&T's System V maintainers (actually I think they populated /usr/lbin)
- SGI, who shipped their own programs in /usr/local (it was local
  relative to System V), and probably other OEMs
- campus computer centers, adding locally-installed (often imported)
  software to vendor distributions
- departments
- maintainers of clusters of machines
- owners or users of individual machines

Aside from the issue of name conflicts (who gets to control
/usr/local?), more and more of the file system becomes fossilised
boilerplate that most people (including administrators) are terrified
(or forbidden) to touch.  If you're in a big enough organisation, you
can end up with

	/company/local/
	/company/division/local
	/company/division/dept/local
	/company/division/dept/group/local
	/company/division/dept/group/my-machine/local

I think we've made a very small step in this direction with
termrc.local, /sys/lib/sysconfig/termrc, namespace.local and
namespace.$sysname.  One litmus test for when fear is driving these
decisions is when people become afraid to edit files with `local' in
their names and want to add another level of indirection.  With the
availability of dumps (or RCS on Lunix), there's little reason to be
afraid of editing files.