help rdump to Sun 150MB tape

[Don Buchholz]

Help!  I've seen (and saved) 5 articles on rdump'ing to Exabytes tapes,
but I'm still unable to get a proper dump to the QIC-150 tape drive on
our Sun 4/300 (SunOS 4.0.3).

As far as I can tell, the rdump command on our RS/6000 (AIX 3.1 w/3001)
completely ignores the "-l" option.  It doesn't matter which of the two
following commands I use:

	rdump -c -l 290000 -0u -f ese3:/dev/nrst8 /usr
	rdump -c -l 2900000 -0u -f ese3:/dev/nrst8 /usr

only about 10% of the tape in the cartridge is used before I am prompted
for the next tape.  I thought -l would specify the capacity of a tape in
512-byte blocks (290000*512 = 148.48 Mbytes).  I figured if that was wrong
at least multiplying the factor by 10 would use more tape -- it didn't :-(.  

Referring to the previous postings and the SunOS man pages concerning the
"-s" and "-l" options to rdump, I tried the following:
	 rdump -0cu -s620 -d20000 -f ese3:/dev/nrst8 /usr
	
assuming that -s was specified in feet and -d was bytes per inch this would
give me 
	620(ft)*12(in/ft)*20000(bytes/in) = 148,800,000 = 148.8 MB.

This only used up one-half of the tape!  

Can anyone give me the correct arguments to use for "-s" and "-l"?
Can anyone tell me why the "-l" option seems to be broken?
Will I need any furthur info to put multiple filesystems on a single
tape, other than specifying the non-rewinding device on the Sun?

Thanks in advance,
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Don Buchholz                         "I wish I'd never gone to Bangkok ..." 
Oregon Graduate Institute            "I wouldn't be so sad I wasn't there now."
buchholz at ese.ogi.edu                  -- J. DeWitt (1985)
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