fdflush - force floppy disk drive to detect disk change
is a band-aid for a common PC hardware problem. Many PC floppy disk drives
can't detect when the disk has been changed. The symptom of this problem is
that when a disk is changed, the drive will continue to read buffered data
from the previous disk rather than new data from the disk presently in the
makes the system believe the disk-change switch has been actuated, and the
system discards the buffered blocks in response to this information.
If you have one of these slightly-broken disk drives, you'll have to run
every time you change a disk.
The kernel uses two different ioctl commands to flush buffers. One's
generic (BLKFLSBUF), one's floppy-specific (FDFLUSH).
calls both, and only reports an error if noth fail.
The name of the floppy disk device, in the form
The default is
Zero: success, one: ioctl error, two: inability to open the
floppy (or other) device, three: usage error.
They're in your hardware.
Try swapping in another floppy drive to see if this problem goes away.