system backups

[prichard devon]

I have borrowed an 8mm Exabyte with which to do a backup of my system.
question is, it looks like "backup" only does one filesystem at a time,
and every time backup runs, it will overwrite the tape.  I want
to backup all data in rootvg, which has several file systems. 

seeing as this is a short-term opportunity to get a complete system backup,
I'd like to get an exact bit-for-bit copy.  from the documentation ;)
I understand that backup is better than tar for this situation.

so, could anyone tell me how to get a full system backup on one tape?

TIA

--
 ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 | Devon Prichard                "The atrocious crime of being a young  |
 | u714092 at eagle.larc.nasa.gov,   man... I shall neither attempt to     |
 | prichard at ias.larc.nasa.gov     palliate nor deny."                   |
 |                                William Pitt, House of Commons, 1741  |
 ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||