ExaByte Dump commands

[Roger Jagoda]

Folks,
 
I have inherited a UNIX system (VAX/ULTRIX) with a SCSI Exabyte (OEM'd 3rd Party as usual) Tape unit. My question regards the parameters for the best "dump"
command use. For example, we're using now:
 
dump <level>usdf 4800 6666 /dev/nrmt1h <f. system>
 
This assumes a density or 4800 and a tape length of 6666 feet which CAN't
be correct. Something is wrong as we can't restore files either..:-( 
 
The tape unit responds with "not a dump tape, I/O error"
 
So, the tapes are SONY 120Ps and the ExaByte manual says the drive is capable
of writing "linear recording density = 43200 bits/inch"
 
Now, isn't this the number we should use instead of 4800 (which sounds more 
like a guess from the old 1600 bpi tape reel days..)?
 
As for feet of tape length, we have asked everyone including the mail
order house where the tapes were bought, NO ONE seesm to know how many
feet of tape come on a 120 tape! The actual model number of the tape is
"P6-120MP" for "Metal Particle". If anyone knows how long these tapes
are can they post an answer? Thanks. Actually, couldn't we just put a
very large number for the lenght (like 100000)? That number is just
so the tape doesn't run off the reel during the dump, right? Well, our
dumps don't take up 2.2G so there's probably no danger of that.
 

Should our dump command be more like:
 
dump <level>udsf 43200 100000 /dev/nrmt1h <f.system> ?
 
Thanks in advance for any pointers or comments!
 
--Roger Jagoda
--Cornell University

-- 
-------------------------------------------------------------------------
Roger Jagoda                          -- My employers don't even like paying
Cornell University                         me, let alone accept responsibility
fqoj at cornella.cit.cornell.edu              for anything I say or do! --