mkbootdisk failure when fd0 is previously mounted

[snookertb <snookertb comcast net>]

I mount a floppy and run the normal mkbootdisk to set up a bootdisk. The 
command completes but the disk is trash.

If I run the same mkbootdisk command with the blank floppy _NOT_ 
mounted, the command completes and the bootdisk works fine.

Anyone know if this is how it should be? I sure trips you up.

tb