tape to tape copy

[John Morris]

Problem: copying a tape that is in "boot" format.
One method involves the 'dd' command but this involves having enough
disk space to accomodate the file.
Question: Is there a way, if you have two cartridge tape drives, to
directly move the data from one tape onto the other through a reasonable 
size buffer.
My computers are SUN's, mostly 4's of one variety or another.  I have a couple
external SCSI cartridge tape drives and think this should be do-able.

by the way, how do you 'make' the boot format tape?