5.11. Disks without filesystems

Not all disks or partitions are used as filesystems. A swap partition, for example, will not have a filesystem on it. Many floppies are used in a tape-drive emulating fashion, so that a tar (tape archive) or other file is written directly on the raw disk, without a filesystem. Linux boot floppies don't contain a filesystem, only the raw kernel.

Avoiding a filesystem has the advantage of making more of the disk usable, since a filesystem always has some bookkeeping overhead. It also makes the disks more easily compatible with other systems: for example, the tar file format is the same on all systems, while filesystems are different on most systems. You will quickly get used to disks without filesystems if you need them. Bootable Linux floppies also do not necessarily have a filesystem, although they may.

	$ dd if=/dev/fd0H1440 
	of=floppy-image
	2880+0 records in
	2880+0 records out
	$ dd if=floppy-image 
	of=/dev/fd0H1440
	2880+0 records in
	2880+0 records out
	$