<p>There are two types of automounters in linux; <em>AMD</em> and <em>autofs</em>. AMD is the
automount daemon, and supposedly works like the SunOS AMD. It is implemented in user space, meaning it's not part of the kernel. It's not necessary for the kernel to understand automounting if you NFS mount to the local host, through the AMD daemon, which routes all automount filesystem traffic through the NFS system. Autofs is a newer system assisted by the kernel, meaning that the kernel's filesystem code knows where the automount mount points are on an otherwise normal underlying fs, and the automount program takes it from there. Only autofs will be described in this mini-howto.
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Autofs is implemented in kernel-space, so your kernel must have support compiled in. All versions of the kernel starting from 2.2.xx supports autofs.
<p>The automount program and its configuration files are also necessary; using the rpms. The RedHat distribution has this package available as part of the installation.
<p>Installing the RPM packages will get you to this point easily enough, but here's the part you might not be sure about if you haven't done this before.
Auto.misc is a "map file". The map file can have any name; this one is named auto.misc because it originally controlled /misc. Multiple map files can be defined in auto.master.
My auto.misc looks like this:
<verb>
kernel -ro,soft,intr ftp.kernel.org:/pub/linux
cd -fstype=iso9660,ro :/dev/cdrom
zip -fstype=auto :/dev/hdd4
floppy -fstype=vfat :/dev/fd0
</verb>
<p>
The first column (the "key") is the mount point. In this case it would be
/auto/floppy or whatever. The middle set are the options; read the mount
manpage for details on this. And the last column specifies where the fs
comes from. The "kernel" entry is supposed to be an NFS mount. The : on all
If automount is setup properly, whatever mount point you're looking for will be there if you try and use it, even though you don't see it when not in use. If you're browsing the directory with a
graphical tool, you may need to type in the name manually; most programs will try what you give it, and the drive will be mounted before it notices. Unfortunately not
being able to choose from the available invisible mount points is probably the
major drawback of autofs. If it really bugs you, edit the configuration files.
(Hint, the ones that end in .c for "configuration")
One workaround several people have tried is to create symbolic links to where automount will create something once it's mounted. This will likely prevent the program from complaining a directory doesn't exist (if the mount works, that is) but careless directory listings will cause filesystems to be mounted.
<sect1>How do I see what's mounted?
<p>
The <tt>df</tt> command. <tt>mount</tt> with no options will do the same, plus show the options its mounted with.
<sect1>I put in a win95 disk ("vfat") and it was autodetected as only a regular FAT disk.
This is not a problem with automount.The "auto" fs type does not attempt a vfat mount before it successfully mounts an MS-DOS filesystem. VFAT is an extension of the basic FAT filesystem inorder to provide Windows 95 and Windows NT with long filenames.
According to one of the authors of mount, since mount is only a wrapper around a system call which must specify the filesystem type, it's still the responsibility of the user to come up with the fs type. Having mount take a list of filesystems to try in order, rather than the current "heuristic" is under consideration. Some users have simply not compiled msdos into the kernel; this prevents it from being tested prior to vfat. This will work for most people; a few actually need msdos fs and there is actually a work around.
You have to copy the /proc/filesystems as /etc/filesystems and edit it to change the order such that vfat appears before msdos.(Thanks Mark)
Check the man page for mount for some of the options, such as setting the uid=value or umask=value options. One option that appears to be missing for FAT filesystems is mode=value. Sorry. Check in with the people who do mounting.
Please mail me to <url url="mailto:Rahul Sundaramsundaram@yahoo.co.in" name="Rahul Sundaram"> in case of any suggestions,improvements or if you have any bright ideas.