Follow Techotopia on Twitter

On-line Guides
All Guides
eBook Store
iOS / Android
Linux for Beginners
Office Productivity
Linux Installation
Linux Security
Linux Utilities
Linux Virtualization
Linux Kernel
System/Network Admin
Scripting Languages
Development Tools
Web Development
GUI Toolkits/Desktop
Mail Systems
Eclipse Documentation

How To Guides
General System Admin
Linux Security
Linux Filesystems
Web Servers
Graphics & Desktop
PC Hardware
Problem Solutions
Privacy Policy




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.

One reason to use raw disks is to make image copies of them. For instance, if the disk contains a partially damaged filesystem, it is a good idea to make an exact copy of it before trying to fix it, since then you can start again if your fixing breaks things even more. One way to do this is to use dd:
	$ dd if=/dev/fd0H1440 
	2880+0 records in
	2880+0 records out
	$ dd if=floppy-image 
	2880+0 records in
	2880+0 records out
The first dd makes an exact image of the floppy to the file floppy-image, the second one writes the image to the floppy. (The user has presumably switched the floppy before the second command. Otherwise the command pair is of doubtful usefulness.)

  Published under the terms of the GNU General Public License Design by Interspire