Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!rutgers!cs.utexas.edu!uunet!ladcgw!rdahp!scott
From: scott@rdahp.UUCP (Scott Hammond)
Newsgroups: comp.sys.hp
Subject: HP9144 cartridge tape drive doesn't stream with HP tape
Keywords: HP9144, cartridge tape, HPUX
Message-ID: <234@rdahp.UUCP>
Date: 12 Jun 89 18:27:49 GMT
Reply-To: scott@rdahp.UUCP (Scott Hammond)
Organization: R & D Associates, Marina del Rey, CA
Lines: 29

System: HP9000/300 running HPUX 6.2, with HP9144 Cartridge tape drive

I noticed something unusual last week.  I was trying the -S 8 option to
tcio which specifies a buffer size for talking to the tape drive which
lets the computer keep up with the tape drive so it can stream (crummy
explanation but you get the idea, note this only works for certain tape
drives).  Upon trying it, I discovered it only worked for 3M
HP-compatible tapes (DC 600HC), and did not work with HP tapes.  This
also shows up with mediainit.  I tried forcing a mediainit on a 600' HP
tape, and it took well over 3 hours.  The same on a 3M 600' tape
required about an hour. 

The mediainit on the HP tape did not help matters when I retried writing
to the tape. 

So, what is happening?  Is the low-level format that different?  I don't
know much about tape formatting, but I get the impression that each leg
of the serpentine track reaches from one end of the tape to the other on
the 3M tape, but is broken up into much smaller chunks on the HP tape. 
Does this sound reasonable?  Am I doing it wrong?  Is this machine
capable of reformatting cartridge tapes?  (and of course, if so, how?). 
Have I gotten hold of some old HP tapes?  (I didn't buy them, they were
received from another site). 

Thanks for any and all information.
--
Scott Hammond,  R & D Associates, Marina del Rey, CA  (213) 822-1715
: {tah386,randvax,ladcgw,<site-with-router>}!rdahp!scott
:  scott@harris.cis.ksu.edu