Hi-
        There IS a document for GNU tar that was provided with - oh ,
gee, I think 1.10.  It is now somewhat out of date.  Anyway, I 
believe that if you want to tar out to multi-volume floppies
you want to do something like this

tar cvMbf 15 /dev/fd0 .

The block size should be the number of sectors in a track on 
your floppy (that is, 15 for 5.25", 18 for 3.5".)  Otherwise
the write fails in the middle of a block and all hell breaks
loose.  I haven't actually TRIED this on Linux, but I do 
read floppies on Linux all the time that were made this way
on a Sun.  

Also, you can't use the -Z compression option along with the
-M multi-volume option.  Please also note that case is important
with the options.

-- 
Steve Hanson - FERMILAB, Batavia, Il.
hanson@pogo.fnal.gov or hanson@fnal.fnal.gov