Date: Sun, 08 Nov 1998 22:20:47 -0600 From: David Kelly <dkelly@hiwaay.net> To: Bryce Newall <data@dreamhaven.net> Cc: Jordan Krushen <jkrushen@home.com>, freebsd-questions@FreeBSD.ORG Subject: Re: Tape backup questions Message-ID: <199811090420.WAA03076@n4hhe.ampr.org> In-Reply-To: Message from Bryce Newall <data@dreamhaven.net> of "Sun, 08 Nov 1998 18:25:13 PST." <Pine.NEB.3.96.981108181906.15750j-100000@ds9.dreamhaven.org>
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Bryce Newall writes: > On Sun, 8 Nov 1998, Jordan Krushen wrote: > > > I've just added a Seagate TapeStor 4/8Gb SCSI drive to my 2.2.7 system, and > > I'm having a hard time figuring out how to have multiple sessions added to > > the tape. When using tar with /dev/nrst0 for two consecutive files, only > > the first file written to the tape remains. > > Tar doesn't allow you to create archive files on a tape. Rather, it sees > the tape itself *as* the archive file, and allows you to add files to and > extract them from the archive file. If you want to add to an existing > tape archive, you should theoretically be able to use the -A (append) > switch on the tar command. (I've never actually tried this, so I can't > verify that it actually works.) Otherwise, tar will erase the header on > the tape and start a new one. I too have never bothered with the -A flag. However one should be able to append a *tape* file after the first archive as Jordan is attempting with the no-rewind tape device. Considering the evidence stated that only the first session survives on the tape then somebody is having problems finding the 2nd. Jordan: "tar -tvf /dev/nrst0" is not going to show all the files the first time thru. After you see the first set repeat the same command and you should see the 2nd set. Playback is same as recording, you invoked tar twice to create, you have to invoke twice to read. You could get to the 2nd set with "mt rew; mt fsf 1" rather than using tar to forward past the first tape file. I write multiple "archives" to a single tape all the time. The tcopy(1) utility goes out of its way to detect multiple "tape files". The practice is *very* common. -- David Kelly N4HHE, dkelly@nospam.hiwaay.net ===================================================================== The human mind ordinarily operates at only ten percent of its capacity -- the rest is overhead for the operating system. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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