21.6. The GRUB Boot Loader Module

As the name suggests, this module allows you to set up GRUB. Like the LILO module, you enter it from the Hardware category and the main page shows a list of icons—one for each boot-time option. Figure 21.2 shows an example.

The module's icon will only appear if Webmin detects that GRUB is installed on your system. If it is not visible or if an error is displayed when you enter the module, GRUB is not installed. If so, LILO is probably being used instead and you should use the Linux Boot Loader module.

One peculiarity of GRUB is that internally it refers to all hard disks by their BIOS disk number. The first drive identified by the BIOS is hd0, and hd0,0 is the first partition on that drive. On a system with only IDE hard drives, this numbering is quite simple—BIOS disk 0 is the primary master, or /dev/hda on Linux. Disk 2 (called hd1 by GRUB) is the primary slave, and so on. On a system with SCSI and IDE drives, however, things get more complex. IDE disks usually come before SCSI in the BIOS ordering, but this may be reversed on some systems. Fortunately, the GRUB module in recent versions of Webmin can automatically detect the relationship between Linux device files and BIOS disk numbers.