Juan Carlos Castro y Castro writes:
> what's so special about /var?
/var is universally available, and was almost universally available
three years ago; it usually has lots of space; it is not shared across
NFS. So people can just go ahead with the installation, with no risk of
incorrect file sharing and with minimal risk of installation failure.
More and more systems are being shipped with /opt, where each package is
expected to have its own directory structure. Unfortunately, /opt is
normally shared among hosts with the same architecture, like /usr;
there's no place for machine-specific package directory structures.
It's clearly an error for file storage to determine the API. Dozens of
programs, and countless user scripts, broke when /usr/spool/mail moved
to /var/spool/mail. Hundreds of installation scripts broke when /usr/man
moved to /usr/share/man. Sun figured out its mistake by the time it
introduced kernel-specific file sharing---notice the symlink from
/usr/sbin/adb to /usr/kvm/adb---but we're still stuck with / and /usr
and /usr/share. It's particularly depressing that all this complexity is
visible on single-user machines that don't share any files.
I'd like to see a standard place for package directories, independent of
file storage. The obvious name is /package: e.g., /package/lprng, with
programs in /package/lprng/bin and data in /package/lprng/spool.
Of course, packages are constantly upgraded, and you shouldn't have to
remove the old version of a package to try out the new version. So
/package/lprng is actually a symlink to /package/lprng-3.7.2. The
upgrade script moves data from lprng/spool to lprng-3.7.2/spool, stops
the old lprng, switches the symlink, and starts the new lprng.
On systems that share files, the package manager can automatically set
up appropriate symlinks, using some system-specific configuration and a
small amount of sharing information included in the package:
/package/lprng-3.7.2/src -> /shared/dist/lprng-3.7.2/src
/package/lprng-3.7.2/bin -> /shared/syst/openbsd-i386/lprng-3.7.2/bin
But the only program that cares about this is the package manager; and
systems without file sharing don't need /shared at all.
I mentioned this design on the FHS list a couple of years ago, and set
up a mailing list for it (send mail to [EMAIL PROTECTED]),
but not many people were interested. Bummer.
---Dan
