Once the kernel is loaded and the boot-code jumps to it, the kernel will initialize itself, trying to determine what hardware is present and so on; it then needs to find a root filesystem.
Presently we support the following types of root filesystems:
This is the most normal type of root filesystem. It can reside on a floppy or on hard disk.
While this is technically possible, it is not particular useful because of the ``FAT'' filesystem's inability to deal with links, device nodes and other such ``UNIXisms''.
This is actually a UFS filesystem which has been compiled into the kernel. That means that the kernel does not really need any hard disks, floppies or other hardware to function.
This is for using a CD-ROM as root filesystem.
This is for using a fileserver as root filesystem, basically making it a diskless machine.