A block is a data allocation "unit", the smallest amount of storage space that can be allocated. It can be a single sector or a cluster of 2 or more sectors.
A bad block is a sector or cluster that can't be read.
Defragmenting will NOT help you in this case.
Causes:
The floppy is formated using a format or file system that is not supported by your device. Any data contained is very probably intact. There is nothing wrong with the floppy nor the drive.
A sector data is corrupted. Dome data is lost. If it's a key sector, the data is intact but can't be accessed as you can no longer locate it. The data that tels you where the rest of your data is located is lost.
You should be able to retreive your data with some tools.
The floppy is physicaly damaged. The floppy is no longer usable. Any data contained on it is effectively lost. With some luck, some data maybe could be rcovered, but will probably have some degree of corruption.
If you can't access several floppies, even after you have formated one on that drive, OR you can't even format any floppy, then the floppy drive is dead.
Kualinar
March 2010
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix computer hardware.