Hurd FS hierarchy (was Re: LD_LIBRARY_PATH troubles)

[Richard Kreuter]

On Fri, Mar 15, 2002 at 12:21:56PM -0600, Carl Wilhelm Soderstrom wrote:

> > Probably very few of us do, seeing as our standard practice of
> > making "/usr" is a symlink to "." makes /X11R6 and /usr/X11R6 the
> > same thing ;)
>
> hmm, ok. I'm still learning the Hurd filesystem layout. so far, it
> had looked like the standard linux-ish tree with some extra bits
> stuck on (like /hurd).

  (The following is mostly documented here and there, though maybe not
all in one place.)

  The filesystem hierarchy is mostly compliant with that specified in
the Filesystem Hierarchy Standard (included in the debian-policy
package, and in Debian Policy), except for some details specified in
GNU Standards (package gnu-standards, though the most recent version
of that package doesn't contain the most recent set of GNU standards).

  The main difference at the moment between FHS and the hierarchy now
used is that /usr is a symlink to /.  /usr historically is the result
of the means of distribution of Unix: a small root tape and a big /usr
tape.  The FHS distinguishes a desire to maintain a root partition as
a minimal filesystem needed to boot and restore a system; everything
not essential goes into either /usr or /var, depending on whether the
files are static or variable, shared among hosts, and so forth.

  The X11R6 directory is an artifact of the X build process.  It is
'reserved' by FHS for the X Window System (FHS section 4.1), though
Debian policy prohibits putting much new into it (see Debian Policy
12.8.7), and it isn't used very much by all the gui layers that have
come along in the last decade or so (e.g., I don't think that either
GNOME or KDE use the X11R6 directory as a root for installation by
default; GNUstep doesn't, and my experience with non-free desktops on
non-free systems suggest that they don't either).

  Eventually, there will be a server among the Hurd, called shadowfs,
for overlaying the contents of one filesystem on another.  This way,
the file hierarchy that the FHS specifies belongs in /usr will be able
to exist on a separate store (e.g., a separate drive partition, or a
network accessbile filesystem, or a file in some filesystem), while
its root directory will also be the system's root directory.  So,
e.g., the contents of /lib on the 'root partition' will also be the
contents of /lib on the 'usr partition', and will all be found in /lib
on the system.

> yes, I'm new to the Hurd. after 3 attempts, I finally found a box
> that it would actually boot on (my laptop); but haven't gotten so
> far as to install X or the like. (lack of networking doesn't help,
> and lack of time hurts worse).

  Lack of networking doesn't help (I installed GNU/Hurd on a laptop
too, and only got networking when I bought a port replicator, which,
luckily, was cheap).  There are documents available describing how to
use apt and another operating system to fetch and install packages,
provided that both GNU/Hurd and the other operating system can access
a shared filesystem.  For now that means the other os has to be a
GNU/Linux (may I suggest Debian :)) or a BSD.

Hope that Helps,
Richard
kreuter at ausar.rutgers.edu
--

"You will be hungry tonite; order takeout now."