Creating images of floppy diskettes with Linux or DOS

If you want to archive floppies–a good idea, since a floppy disk can sit for months unused and go bad between the time you made it and the time you really needed it, and since it’s hard to shuffle through a collection of hundreds of disks and find the one you need–Linux is an ideal environment for it. To create a disk image, use the following command:
dd if=/dev/fd0 of=filename bs=18k

The if parameter tells it the input device or file (the floppy drive, in this case), and the of parameter tells it the output device or filename. The bs parameter is block size. Most people use a block size of 512, since that’s the size of a disk sector, but it’s slightly faster to write an entire track at once. The speed increase is only slight, but I thought you might like to know. Floppies are already slow enough as it is. I’ve also heard allegations that reading and writing entire tracks at once is more reliable, but I can’t substantiate those claims.

To write out a disk image, simply reverse the if and of parameters:

dd if=filename of=/dev/fd0 bs=18k

Disk images in this format are portable; any Unix can rewrite them to disk, as can the DOS/Windows utility rawrite, which you’ll find on virtually every Linux installation CD. Most other popular disk-imaging programs for DOS and Windows can handle this file format as well.

If you want an equivalent DOS/Windows command-line program to create dd/rawrite-compatible disk images, check out fimage. You can even make those images self-extracting executables with sfx144, if you wish.

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