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Path: euryale.cc.adfa.oz.au!newshost.carno.net.au!harbinger.cc.monash.edu.au!news.rmit.EDU.AU!goanna.cs.rmit.edu.au!news.apana.org.au!cantor.edge.net.au!news.teragen.com.au!news.access.net.au!news.mel.connect.com.au!munnari.OZ.AU!news.ecn.uoknor.edu!news.ysu.edu!news.radio.cz!newsbastard.radio.cz!news.radio.cz!CESspool!news-feed.inet.tele.dk!news.maxwell.syr.edu!news.mathworks.com!fu-berlin.de!unlisys!cs.tu-berlin.de!news.informatik.uni-kiel.de!usenet From: Dagobert Michelsen <dam@informatik.uni-kiel.de> Newsgroups: comp.unix.bsd.freebsd.misc,comp.arch.storage Subject: Re: Tape file system Date: Wed, 26 Mar 1997 16:51:52 +0100 Organization: Institute of Computer Science, University of Kiel, Germany Lines: 43 Message-ID: <33394618.3F77@informatik.uni-kiel.de> References: <5h0pfc$7vg@fu-berlin.de> <slrn5jbi5f.t0.ripley@nortobor.nostromo.in-berlin.de> <01bc3946$15859060$6330fa9e@org-qsar2.chem.msu.su> <5ha6ju$3i1$2@otis.netspace.net.au> <5hbbdq$8d9$1@gail.ripco.com> NNTP-Posting-Host: flash.informatik.uni-kiel.de Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Mailer: Mozilla 3.0 (X11; I; SunOS 5.5.1 sun4u) Xref: euryale.cc.adfa.oz.au comp.unix.bsd.freebsd.misc:37878 comp.arch.storage:12961 David Richards wrote: > > >: I thought about this once (not for Unix) but dropped the idea > >: after reading in the HP SureStore manual that cartridges are > >: certified for 2000 tape > >: start/stops, or approx. 100 normal backups. > >: I guess filesystem-type access will eat this in no time at all. With DAT the lifecycle is even shorter (especially with 120m tapes). Keep in mind, however, that IMHO the critical point with DAT tapes is the insertion process because the tape is wound around the head. This lengthens the tape every time a small amount. After a certain number of usages the tape has been stretched so much that the head cannot synchronize to the next track and the tape becomes almost unreadble. > >I've seen them for Mac (cant remember the name) Amiga (tapeworm) > >and Dos (datman). The name of the Mac program is "DeskTape". > I recall seeing source code for a SVR4 version released a couple of > years back, not sure of the package name. I believe it treated a > tape as if it was a WORM drive, handy for archive purposes. The SVR4-program might work similar to the Mac-program. Tapes on the Mac are handled like any other removable media. Inserting a blank tape brings up a requester for formatting, usage is like a normal disk. The directory is held in a file on the system disk and written back at the end of the tape if modifications were made. Deletions are only marked in the directory. That means that all writing occurs only in form of an append at the end of the tape. Hope it helps -- Dagobert Michelsen -- Dagobert Michelsen http://www.informatik.uni-kiel.de/~dam dam@informatik.uni-kiel.de Phon/Phax:+49 431 96499 "They called me a whore!" "See how the people can be mistaken. They call me Admiral even though i no longer sail the sea."