The latest Linux Distributions mount drive partions using a "Universally Unique IDentifier" (UUID) instead of the device name (/dev/sda?). A UUID is a 128-bit number used to uniquely identify some object or entity on the Internet. Depending on the specific mechanisms used, a UUID is either guaranteed to be different or is, at least, extremely likely to be different from any other UUID generated until 3400 A.D. The UUID relies upon a combination of components to ensure uniqueness. A guaranteed UUID contains a reference to the network address of the host that generated the UUID, a timestamp (a record of the precise time of a transaction), and a randomly generated component. Because the network address identifies a unique computer, and the timestamp is unique for each UUID generated from a particular host, those two components should sufficiently ensure uniqueness. However, the randomly generated element of the UUID is added as a protection against any unforseeable problem.
If you reformat a partition or add one yourself to fstab, you can determine the UUID using the following terminal command.
$ ls -l /dev/disk/by-uuid
lrwxrwxrwx 1 root root 10 2007-08-15 04:04 1C80B6A180B680B6 -> ../../sda1
lrwxrwxrwx 1 root root 10 2007-08-15 04:04 3a6c36a6-14bc-4502-93f8-ec1468169626 -> ../../sda5
lrwxrwxrwx 1 root root 10 2007-08-15 09:04 43C7-C4D3 -> ../../sda3
lrwxrwxrwx 1 root root 10 2007-08-15 04:04 9e39618d-0430-4c5e-898d-d39f760f753b -> ../../sda6
lrwxrwxrwx 1 root root 10 2007-08-15 04:04 acdcc1fe-03c0-4e27-87d9-733bbf032c65 -> ../../sda7
The output from "df" shows:
$ df
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/sda6 11535344 5159484 5789892 48% /
varrun 1028868 80 1028788 1% /var/run
varlock 1028868 4 1028864 1% /var/lock
udev 1028868 128 1028740 1% /dev
devshm 1028868 0 1028868 0% /dev/shm
lrm 1028868 18316 1010552 2% /lib/modules/2.6.15-28-686/volatile
/dev/sda5 90297 13840 71640 17% /boot
/dev/sda7 7692876 4690872 2611228 65% /home
/dev/sda3 10285584 5725320 4560264 56% /mnt/data
Contents of fstab:
$ cat /etc/fstab
# /etc/fstab: static file system information.
#
# <file system> <mount point> <type> <options> <dump> <pass>
proc /proc proc defaults 0 0
# /dev/sda6
UUID=9e39618d-0430-4c5e-898d-d39f760f753b / ext3 defaults,errors=remount-ro 0 1
/dev/sda5 /boot ext3 defaults 0 2
# /dev/sda7
UUID=acdcc1fe-03c0-4e27-87d9-733bbf032c65 /home ext3 defaults 0 2
# /dev/sda3
UUID=43C7-C4D3 /mnt/data vfat rw,auto,uid=1000,gid=100,umask=022 0 0
/dev/sda8 none swap sw 0 0
/dev/scd0 /media/cdrom0 udf,iso9660 user,noauto 0 0
/dev/fd0 /media/floppy0 msdos rw,user,noauto 0 0