Path: utzoo!censor!geac!torsqnt!news-server.csri.toronto.edu!cs.utexas.edu!sdd.hp.com!usc!ucselx!bionet!agate!shelby!neon!neon!peda From: peda@simplicity.Stanford.EDU (Bill Codding) Newsgroups: comp.unix.admin Subject: Re: Advice on change of tape drive please. Message-ID: Date: 22 Nov 90 00:45:24 GMT References: Sender: news@Neon.Stanford.EDU (USENET News System) Organization: None to Speak Of Lines: 64 In-Reply-To: operator@cs.exeter.ac.uk's message of 20 Nov 90 10:49:52 GMT In article operator@cs.exeter.ac.uk (Sue Charles) writes: We at the moment have a QIC-11 tape drive on our sun and are backing up onto 3M DC300A -300ft Tapes DC300XL/P 450ft Tapes DC600A 600ft Tapes using the maximum tape capacity. In the new year we will be installing a QIC-150 drive. Which (if any) of the above tapes would I still be able to use If you want some really confusing, conflicting information on this subject, call the 3M hotline. Want to be more confused? Call the drive manufacturer. We had similar questions. After what amounts to several hours of experiments and being on the phone with the above goons, the following information finally falls out. 1) Using our Archive 2150S QIC-150 drive (Stellar GS1000), we can read AND write QIC-150, read ONLY QIC-24, and neither read NOR write QIC-11. 2) Our Sun-3 was able to write both QIC-11 (nrst0) and QIC-24 (nrst8). Only the higher density is readable in the QIC-150 drive. I believe Sun-2's only wrote QIC-11. 3) 3M said you should not use more than one type of tape in a drive, as the heads "wear in" to one type; using another can cause reliability problems. a) 3M explicitly said to not combine DC600A's and DC300XL/P's on one drive. Upon pressing them for details, however, the two seem to be the same form factor, same thickness vinyl, just a different coating/oersted rating. I find it hard to believe you cant mix different _coatings_ in your drive.... Archive says it is OK to read the occasional DC300XL/P in your QIC-150 drive, though. b) Archive says you can use either DC600A or DC6150 on their QIC-150. They say the physical medium is the same, so no wear problems. However, the 6150 has an additional capstan (roller) and a wider opening in the plastic housing. The tape identification marks tell the tape drive to write more tracks on the 6150, since the housing hole allows more head clearance. Thus, 120MB on a 600A, and 150MB on a 6150. c) The 6150 is actually Archive's recommended tape for the QIC-150; the 600A was originally designed for a lower capacity drive (hence the "60MB" marking on the case) but will work writing fewer tracks. d) Archive says you cannot interchange [DC6150/DC600A] and the DC6250. The 6250 is thinner tape, and causes the head to wear more (or less??) convex-ly. 4) 3M sometimes gives different MB ratings to tapes which have the same form factor, coating, thickness, etc; the only difference being that they are marketed for use on drives which write different numbers of tracks! Whatta waste of brain space. This isn't even my job. I'm charging them $10,000,000 for my time. ------------------------------------------------------------------------ Bill Codding (415)493-3554 (w) Research Engineer (415)751-5484 (h) P.E.D.A. peda@simplicity.Stanford.EDU ------------------------------------------------------------------------