||<>|| {{attachment:IconsPage/hdd.png}} Linux prefers to use '''UUID''' (Universally Unique Identifier), '''LABEL''', or symlinks to identify media storage devices on a system. Using device assignments (like {{{/dev/hd*#}}} or {{{/dev/sd*#}}}) is not preferred since these can change between system boots: * all filesystems should be specified by {{{UUID=}}} or {{{LABEL=}}} for each partition. * all physical devices should be specified by a symlink, like {{{/dev/cdrom}}} for a cd drive and {{{/dev/disk/by-id/...}}} for each physical hard drive. {{attachment:IconsPage/editor.png}} The files for which UUID is most critical: * {{{/boot/grub/grub.cfg}}} * {{{/etc/fstab}}} * {{{/etc/initramfs-tools/conf.d/resume}}} This page uses the terminal a lot, so if you are new to this, see [[UsingTheTerminal]]. The [[Fstab]] page provides some excellent examples of UUID in action. = Finding UUIDs = {{attachment:IconsPage/note.png}} UUIDs can be determined using the {{{blkid}}} command. This command lists UUIDs for all attached devices (mounted or not). {{attachment:IconsPage/example.png}} Here are examples (your output will be different, but similarly formatted). The command: {{{ sudo blkid }}} produces an output similar to: {{{ /dev/sda1: TYPE="ntfs" UUID="72C0DE8EC0DE57C5" LABEL="windows" /dev/sda2: UUID="30fcb748-ad1e-4228-af2f-951e8e7b56df" SEC_TYPE="ext2" TYPE="ext3" /dev/sda5: TYPE="swap" UUID="8c4e69f8-5074-42c0-8134-0b2429c4c02c" /dev/sdb1: SEC_TYPE="msdos" UUID="4848-E35A" TYPE="vfat" }}} Alternatively you can list them from their listing in your root filesystem: {{{ ls -l /dev/disk/by-uuid/ }}} produces an output similar to: {{{ total 0 lrwxrwxrwx 1 root root 10 2008-06-04 03:10 30fcb748-ad1e-4228-af2f- 951e8e7b56df -> ../../sda2 lrwxrwxrwx 1 root root 10 2008-06-07 16:51 4848-E35A -> ../../sdb1 lrwxrwxrwx 1 root root 10 2008-06-04 03:10 72C0DE8EC0DE57C5 -> ../../sda1 lrwxrwxrwx 1 root root 10 2008-06-04 03:10 8c4e69f8-5074-42c0-8134-0b2429c4c02c -> ../../sda5}}} = Using LABEL = {{attachment:IconsPage/note.png}} Labels can be very useful for external media, like flash drives and USB hard drives since these are generally automounted by {{{hal}}} (Hardware Abstraction Layer). If a device has a label, it will be mounted at the {{{/media/