On Tue, 1 Apr 1997 09:39:11 +0200,
Nico van Eikema Hommes <hommes@derioc1.organik.uni-erlangen.de> wrote:
> >For that matter, i don't think i have enough room left on my drive for
> >the comp stuff, but i do have a zip set up.  putting /usr/src there is
> >obvious, but what about the compilers?  Before I get a truly unbearable
> >number of files i cant find :), what extra directories should actually
> >be links to the zip??
> 
> Installing "comp" puts a lot of files in /usr/include and /usr/lib. The
> compilers are in /usr/bin or so. You'll probably have to set up your
> environment with an overwhelming number of soft links.
> Should this turn out to be too tedious: let me know where the sources
> are and I can give it a try.

It's not bug-free yet, but you can use union fs for this.

Say you have your Zip drive mounted on /zip and extracted the comp12
there.  So you have /zip/usr/bin, /zip/usr/include, /zip/usr/lib, etc.
Now, you want to access xxx in /zip/usr/bin (= /zip/usr/bin/xxx) as
your /usr/bin/xxx, right?  You can do like this:

	mount -t union -o -b /zip/usr /usr

Then you will see /zip/usr/bin/xxx as /usr/bin/xxx provided that you
didn't have xxx in /usr/bin before you do the above.  BTW, I don't
think "mount -t union -o -b /zip /" is a wise action (no, I haven't
tried that one).

One popular use of union fs is like this:

	mount -rt cd9660 /dev/cd0a /cdrom
	mount -t union -o -b /cdrom/foo/bar/src /site/local/foo/bar/src

And you can "cd /site/local/foo/bar/src; make" or whatever without
copying all the source files to the disk.  You will have the resultant
object files and identical directory structure, however.

For more information, try "man mount_union".

Cheers,

Ken