Return to BSD News archive
Path: euryale.cc.adfa.oz.au!newshost.carno.net.au!harbinger.cc.monash.edu.au!news.cs.su.oz.au!inferno.mpx.com.au!nsw1.news.telstra.net!wa.news.telstra.net!news.telstra.net!psgrain!iafrica.com!uct.uni.net.za!ru.uni.net.za!und.uni.net.za!csir.uni.net.za!wits.uni.net.za!howland.erols.net!cs.utexas.edu!ennfs.eas.asu.edu!nntp.dist.maricopa.edu!rtd.com!dgy From: dgy@rtd.com (Don Yuniskis) Newsgroups: comp.unix.bsd.freebsd.misc Subject: Re: Tape file system Date: 25 Mar 1997 18:21:47 GMT Organization: CICDO Lines: 38 Message-ID: <5h953r$lpc@baygull.rtd.com> References: <5h0pfc$7vg@fu-berlin.de> <slrn5jbi5f.t0.ripley@nortobor.nostromo.in-berlin.de> <01bc3946$15859060$6330fa9e@org-qsar2.chem.msu.su> NNTP-Posting-Host: seagull.rtd.com Xref: euryale.cc.adfa.oz.au comp.unix.bsd.freebsd.misc:37888 Eugene Radchenko <genie@qsar.chem.msu.su> wrote: >H. Eckert <ripley@nostromo.in-berlin.de> wrote in article >> gusw@zedat.fu-berlin.de (Gunther Schadow): >> > is it possible to write a file system onto a tape and then mount it >> > like a disk? Wasn't this possible on the VAX? On HP-UX you can even >> > boot from tapes, can't you? When I tried to write a disklabel onto >> > the tape, it doesn't work due to missing IOCTLs for the st0 driver. >> > Newfs doesn't work then either. Will it be easy to emulate a disk >> > with a tape drive? Or do we need a separate tape filesystem driver? >> >> This isn't possible AFAIK. The VAX isn't a good example for this >> as it does this when running VMS (which despite the POSIX tweaking >> is an entirely different operating system) but not under Ultrix. >[...] Sorry, but it *is* technically possible. I had a tape file system running on my 1.1.5.1R box to test the mt driver (9 track) I had written. Adding support for this was just an "exercise" I undertook when writing the driver. I never really "beat on" this type of use since it drastically increases the amount of anxiety I have to deal with watching the transport go through all those contortions. >> If you really want to have some kind of tapefs you'll certainly have >> to write a driver. Why don't you just start writing one ? :-) > >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. You miss the point of a tape based file system. You don't necessarily do it to replace a disk drive (uh, d'uh...). Rather, it gives you a nice "indexed" collection of files that can be accessed as if they *were* a disk. Typically used "read only". Much more convenient than having to 'tar tv' from the tape just to see what's on it! --don