The GRUB bootloader is broken down into different stages. The code contained on the master boot record (MBR) is considered GRUB stage 1. It loads GRUB stage 1.5, which tries to identify the file system type (optional), or it can call GRUB stage 2 directly. Stage 2 is what calls the kernel and loads it into memory. GRUB has its own format for looking through hard disks. The syntax of this format is:
(xdn[,m]) where xd is the drive, n is the number of the disk, and m denotes the partition number.
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