The file /etc/fstab (it stands for “filesystem table”) contains descriptions of filesystems that you mount often. These filesystems can then be mounted with a shorter command, such as mount /cdrom. You can also configure filesystems to mount automatically when the system boots. You’ll probably want to mount all of your hard disk filesystems when you boot, so Debian automatically adds entries to fstab to do this for you.
Look at this file now by typing more /etc/fstab. It will have two or more entries that were configured automatically when you installed the system. It probably looks something like this:
#
# <file system> <mount point> <type> <options> #<dump > <pass>
/dev/hda1 / ext2 defaults 0 1
/dev/hda3 none swap sw 0 0
proc /proc proc defaults 0 0
/dev/hda5 /tmp ext2 defaults 0 2
/dev/hda6 /home ext2 defaults 0 2
/dev/hda7 /usr ext2 defaults 0 2
/dev/hdc /cdrom iso9660 ro,noauto 0 0
/dev/fd0 /floppy auto noauto,sync 0 0
The first column lists the device the filesystem resides on. The second lists the mount point, the third indicates the filesystem type. The line beginning by proc is a special filesystem. Notice that the swap partition (/dev/hda3 in the example) has no mount point, so the mount point column contains none.
The last three columns may require some explanation.
The fifth column is used by the dump utility to decide when to back up the filesystem. In most cases, you can put 0 here.
The sixth column is used by fsck to decide in what order to check filesystems when you boot the system. The root filesystem should have a 1 in this field, filesystems that don’t need to be checked (such as the swap partition) should have a 0, and all other filesystems should have a 2. It’s worth noting that the swap partition isn’t exactly a filesystem in the sense that it does not contain files and directories but is just used by the Linux kernel as secondary memory. However, for historical reasons, the swap partitions are still listed in the same file as the filesystems.
Column four contains one or more options to use when mounting the filesystem. You can check the mount manpage for a summary; see section 5.1 on page 121.