On Thu, Jan 24, 2002 at 01:44:18PM -0600, Peter Seebach wrote:
> I haven't even figured out exactly what it's for.  Actually, that's not quite
> true:  I have a vague belief that the idea is that I can have a read-only
> /usr/src, NFS-mounted to hell and back, and everyone uses /home/obj for
> builds, and it All Just Works.

The big idea for the obj subdirectory stuff had to do with the belief
that you would have your /usr/src on one drive, and /usr/obj on a
second drive.

Then when you did "make obj" at the top of the tree, the /usr/obj tree
would be populated with a directory hierarchy, and the /usr/src tree
would be symlinked into the /usr/obj tree.  Then as you did
"make depend" and finally "make all", the /usr/obj tree would get all
the .o files, along with the binaries and formated man pages.

If you mounted /usr/src from nfs, it would trivial to build the same tree
on all the different architectures in parallel, without any of the builds
overlapping and conflicting with one another.

Given that you need write access into /usr/src for the first run of
the 'make obj' target, you can't really do a read only /usr/src tree,
at least not all the time.  Exporting it read only after the symlinks
have been made does help, as NFS then attempts to do better caching
of contents and directory data.  (or it did on the SunOS 4.X machines
where I first starting doing this)

-Kurt