Format floppy disk under Linux 

Quick format 

mformat a:
It  doesn't record bad block information to the Fat, use mbadblocks for
that.

cmd:mbadblocks 

mbadblocks - tests a floppy disk, and marks the bad blocks in the FAT

mbadblocks a:

Low-level format with verify 

fdformat /dev/fd0

fdformat does a low level format on a floppy disk. Still need mformat to add the MS-DOS filesystem to floppy.