Problems with streaming tape drive

[Paul R Lavoie]

         I have a few questions regarding a 6157-002 tape drive and a
         model 80 with 16 meg. I am using the 3M 6150 tapes in the drive.

         I create a back by filesystem, dumping an 80 meg filesystem. It
         takes aprox 70 minutes and 3 tapes to do it. I am using the    
         following command to back up the filesystem:

         backup -0 -u -v -C500 -f/dev/rmt0 -s11160 (filesystem name)

         Now on to the questions....

         I seem to only get 1.3 meg a minute out of the drive. Is this
         the best I can do?.

         I only seem to be getting about 40 meg per tape. (Best case, let's
         assume it only needs 10 feet of tape 3). Specs say I should get
         about 150 MB/tape. Even if I delete the marketing "fudge factor"
         from 150 MB per tape I should still get about 90 MB/tape. I am
         getting the s param from 620 feet of tape * 18 tracks. Is this
         correct?. 

         As usual, any help would be greatly appreciated.
 
-- 
Paul R. Lavoie                  uunet!mrmarx!paul
Decision Software Company	(617) 576-7800
51 Spinelli Place	
Cambridge, MA 02138