Trying to understand FatInvalidateVolumes

Hi!
How can I reproduce the situation when the following condition in
FatInvalidateVolumes is true:
if (ExistingVcb->Vpb->RealDevice == DeviceToMarkBad) {
?

I used to do this with bulk formatted floppy disks (so the serial number
was the same) and then swap them out. FAT would get confused under
certain circumstances and (as I recall) File Manager/Explorer (this was
a long time ago) would help it understand it was confused.

Tony
OSR