Re: Automounters - more info wanted (was Re: Re: plextor px-708uf: cannot get disk type)
On Tue 27 January 2004 08:06, Lourens Veen wrote:
>
> Then there is autofs
> (http://freshmeat.net/projects/autofs/?topic_id=142, can't find a
> real homepage) and KDE uses fam
> (http://oss.sgi.com/projects/fam/), however I don't think fam
> actually mounts devices by itself, it just watches files. I use
> (parts of) KDE myself and fam is almost always running; it's
> never given me any problems with writing CDs.
It turns out that there is a daemon similar to magicdev, which is
used with KDE: autorun (http://sourceforge.net/projects/autorun/).
From the description:
"autorun automagically recognizes all available CDROMs in the
system, mounts them upon insertion of a media and executes a
possible autorun executable on the CD. The user can remove the
media; autorun will call unmount after that."
I did a quick download and looked through the source, and it seems
that the binary will be called autorun. I also did a search through
the archives and found a reference to supermount
(http://supermount-ng.sourceforge.net/). There is also amd, but
that doesn't seem to be very widely used, and certainly not
installed by default. If someone installed that by hand, they can
probably figure out how to fix it.
So we have the following table of possible automounters interfering
with cdrecord on Linux:
Name Type Process name
magicdev daemon magicdev?
autorun daemon autorun
autofs module + daemon automount
supermount module N/A
Detecting automounters
magicdev and autorun can probably be detected by ps, supermount (or
at least supermount-ng) has a /proc/fs/supermount directory. If you
are running autofs, you likely have a file called /etc/auto.global,
and there is the automount process.
Preventing automounters from interfering
Ideally, an automounter would detect writing in progress and stay
away from the drive while the CD is being written. I don't think
any of the abovementioned automounters has such a feature. As an
alternative, automounting could be disabled for the writer. autofs
is configured through a map file (see the man page) and supermount
is configured through /etc/fstab (see the readme). I don't know
about autorun and magicdev. As a last resort, the daemon-based
automounters could be disabled completely by killing the process
and/or uninstalling. The in-kernel ones would have to be disabled
through their configuration files, by unloading the module or by
recompiling the kernel.
Some other bits of information
- GNOME uses magicdev
- KDE uses autorun, at least on Red Hat
- Mandrake includes supermount, but outside of Mandrake it's
probably rather rare
More info, especially on configuring magicdev and autorun, is still
very welcome!
Lourens
--
GPG public key: http://home.student.utwente.nl/l.e.veen/lourens.key
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