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From: sean@dsl.pitt.edu (Sean McLinden)
Newsgroups: comp.windows.x
Subject: Re: Alternative installation directories for X11R4
Message-ID: <1991Feb23.164951.4655@dsl.pitt.edu>
Date: 23 Feb 91 16:49:51 GMT
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Organization: Decision Systems Laboratory, Univ. of Pittsburgh, PA.
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In article <32602@sequoia.execu.com> keith@sequoia.execu.com (Keith Pyle) writes:
>Is it possible/practical to install X11R4 somewhere other than in
>the default directories of /usr/bin/X11 and /usr/lib/X11?

Yes/no.

It is possible, it may even be practical in some situations, but
my experience doing this on a few different networks is that you
don't want to unless you *absolutely* have to. The problem stems
from the fact that X11 inherited the 4.2bsd-style of file system
organization which, in turn, suffered from a limitation in user
definable library paths for the ld(1) link editor. That limitation
was that ld would search only /lib and /usr/lib (and later,
/usr/local/lib) for ranlib'd archives. Perhaps in keeping with
this tradition, the implementors of X11 chose to root the X11
libraries in /usr/lib (although resources and fonts and things
are in /usr/lib/X11).

In the best of all possible worlds, X11 *should* have been
installed in a single directory rooted in X (or X11) as in:

% ls /usr/X11
adm           bin           etc
lib           src           tmp

or some such thing. Packages such as Serpent, KHOROS, and the
Brown Workstation Environment, do follow this convention. X, does
not.

>Are there any negative aspects for X11 to using an alternate
>installation destination such as I mention?

If you define your X config files correctly, X will build and
run OK. The headache exists because in some (actually many)
cases, contributed and ftp'able software rely on hardcoding
paths to the /usr/lib stuff and, in particular, /usr/lib/X11.
Many applications don't use the /usr/lib/X11/config files for
certain parts of the build causing you problems with resources
and application defaults and even fonts.

This is the simplest case. One in which there is no X distribution
to begin with. A more complicated case exists for something like
the DEC/Ultrix/DECWindows environment where, until your build is
complete and fully tested, you need to maintain separate and distinct
paths. The DEC Ultrix install utility forces you to install the basic
DECWindows distribution so you cannot, easily, start out with a
vanilla Ultrix and build an X on it.

You can, of course, build symbolic links to everything. That
is what we have had to do. In fact, what we ended up doing was
to build a separate X11R4 hierarchy, move to it, and then build
another with the defaults once the DECWindows stuff was completely
purged.

I am hoping that by the time X11R5 comes around there will be
a move toward 4.4ish style file systems and X11 will exist, totally,
in its own hierarchy. Then it will be simpy a matter of a single
link or a single mount point to switch distributions, versions,
whatever.

Sean McLinden
Decision Systems Laboratory
University of Pittsburgh Medical Center