When LILO is written to the floppy boot sector, note that it still can boot any partition.
This floppy was made with boot=/dev/fd0 and was made on this system. It boots linux right from its own partition (hdb2) but will not work on any other machine. This is your "LILO boot disk". You use it when you have trouble with (or don't trust) your MBR.
This is an illustration of what I call an "emergency boot disk". This floppy contains LILO, all the files found in /boot, and a Linux kernel. It is a self-contained system up to the time it mounts the root file system. If you have an intact root file system, this disk can get you going. You can use it to get around trouble with your MBR, lilo installations, and bad kernels (or incorrectly-performed kernel updates).
This disk can be used on other computers. If you know where the file system is you can enter root=/dev/hda2 at the LILO prompt to get Linux running. Even on a computer without Linux, just watching what the kernel prints when it starts can provide a wealth of hardware information about that machine.
You make this disk changing most of the lilo.conf parameters to '/dev/fd0'. See the floppy making section.
The fanciest of the boot disks are the 'rescue disks'. The idea here is to supply a working root file system so that you can actually get into Linux even if your hard disk isn't working. Since there isn't much room on a floppy for all that, most of the schemes use a second floppy to contain the file system. The file system will be stored in a compressed ramdisk--the most visible part being initrd.
Given this flexibility, you can make anything that is of modest size, thus, it is the model for:
- Rescue disks
- System repair disks
- Installation or setup disks
- Special applications (standalone router, telnet terminal, etc.)
Rescue and repair disks can fix more problems than an emergency boot disk but are a little less convenient because you have to swap diskettes each time you restart. They also mount their own file system as root so that the one you're trying to repair has to show up in an alternate place (such as /temp/root).