I think it also needs to be noticed that "base system" in lunixes implies
a huge a mount of stuff

On Fri, Mar 26, 2010 at 2:59 AM, Anthony Sorace <[email protected]> wrote:
>        Unix has two camps for approaching this problem /usr/local and /opt.
> While they're almost never followed well on modern unix systems, the idea is
> basically a global local overlay vs. a per-package overlay.
>
>        The /usr/local approach takes all packages not part of the base
> system and creates a "local root", a global mirror of (roughly) the root
> file system. Those poor souls don't have bind to work with, so everything
> ends up "knowing" to look in /bin and /usr/local/bin, /etc and
> /usr/local/etc, and so on. Packages from multiple sources are all intermixed
> in one /usr/local, so you've basically got the base system vs. everything
> else. EBo's /sys_aps is basically a recreation of /usr/local.
>
>        The /opt model creates per-package trees under /opt, for example
> /opt/SomePackage. Within, it gets a similar looking overlay, but specific to
> that package. It's then up to the user or site admin to determine which
> packages get installed. Based on a similar (but much shorter) conversation
> on inferno-list, a few of us are trying out this model for third-party
> packages within Inferno.
>
>        The Plan 9 approach today is either install everything in /
> (/386/bin, /sys/include, &c) or in your personal home dir and bind as
> needed. The later is irritating on multi-user systems, and the former can
> make maintenance a lot harder. Replica's -c and -s help, but it still
> requires more vigilance from the admin than it seems like it ought to.
>
>        Personally, I've always preferred the /opt model, as it makes it
> easier to tell at a glance what's installed and to work with components
> individually. The (non-)overlay can get unwieldy on Unix, but our namespaces
> make that much easier for us. It also give both admins and users
> package-level control over what gets included.
>
>        Like I said, I and a few others have started playing with this in
> Inferno. If it works reasonably there, I intend to try something similar in
> Plan 9. Anyone likes to beat me to it, I'd love to hear about your results.
>



-- 
Federico G. Benavento

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