grub2: Naming convention
1
1 2 Naming convention
1 *******************
1
1 The device syntax used in GRUB is a wee bit different from what you may
1 have seen before in your operating system(s), and you need to know it so
1 that you can specify a drive/partition.
1
1 Look at the following examples and explanations:
1
1 (fd0)
1
1 First of all, GRUB requires that the device name be enclosed with '('
1 and ')'. The 'fd' part means that it is a floppy disk. The number '0'
1 is the drive number, which is counted from _zero_. This expression
1 means that GRUB will use the whole floppy disk.
1
1 (hd0,msdos2)
1
1 Here, 'hd' means it is a hard disk drive. The first integer '0'
1 indicates the drive number, that is, the first hard disk, the string
1 'msdos' indicates the partition scheme, while the second integer, '2',
1 indicates the partition number (or the PC slice number in the BSD
1 terminology). The partition numbers are counted from _one_, not from
1 zero (as was the case in previous versions of GRUB). This expression
1 means the second partition of the first hard disk drive. In this case,
1 GRUB uses one partition of the disk, instead of the whole disk.
1
1 (hd0,msdos5)
1
1 This specifies the first "extended partition" of the first hard disk
1 drive. Note that the partition numbers for extended partitions are
1 counted from '5', regardless of the actual number of primary partitions
1 on your hard disk.
1
1 (hd1,msdos1,bsd1)
1
1 This means the BSD 'a' partition on first PC slice number of the
1 second hard disk.
1
1 Of course, to actually access the disks or partitions with GRUB, you
1 need to use the device specification in a command, like 'set root=(fd0)'
1 or 'parttool (hd0,msdos3) hidden-'. To help you find out which number
11 specifies a partition you want, the GRUB command-line (⇒
Command-line interface) options have argument completion. This means
1 that, for example, you only need to type
1
1 set root=(
1
1 followed by a <TAB>, and GRUB will display the list of drives,
1 partitions, or file names. So it should be quite easy to determine the
1 name of your target partition, even with minimal knowledge of the
1 syntax.
1
1 Note that GRUB does _not_ distinguish IDE from SCSI - it simply
1 counts the drive numbers from zero, regardless of their type. Normally,
1 any IDE drive number is less than any SCSI drive number, although that
1 is not true if you change the boot sequence by swapping IDE and SCSI
1 drives in your BIOS.
1
1 Now the question is, how to specify a file? Again, consider an
1 example:
1
1 (hd0,msdos1)/vmlinuz
1
1 This specifies the file named 'vmlinuz', found on the first partition
1 of the first hard disk drive. Note that the argument completion works
1 with file names, too.
1
1 That was easy, admit it. Now read the next chapter, to find out how
1 to actually install GRUB on your drive.
1