fdflush - force floppy disk drive to detect disk change
Fdflush 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 drive. Running fdflush 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 fdflush 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). fdflush calls
both, and only reports an error if noth fail.
device The name of the floppy disk device, in the form /dev/fd1 . The
default is /dev/fd0 .
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.
/dev/fdN floppy disk device.
Bruce Perens Bruce@Pixar.com .