On Sun, Dec 25, 2005 at 09:10:34AM -0500, Steven M. Bellovin wrote:
> I've never seen any documentation.  What I'd do, though, is create a 
> file of the proper size -- either by dd'ing from a real floppy or by 
> using /dev/zero -- use vnconfig to turn it into a disk, format it with 
> newfs_msdos, and mount it.

if you want a bootable BSD filesystem on that:
  disklabel -w -r /dev/rfd0a floppy
  newfs /dev/rfd0a
  /usr/mdec/installboot -f /usr/mdec/biosboot.sym /dev/rfd0a

on i386, have a look at:
  /usr/src/distrib/i386/floppies
  /usr/src/distrib/common/Makefile.tarfloppy

Ben