Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!watmath!clyde!cuae2!ihnp4!ulysses!ggs From: ggs@ulysses.UUCP Newsgroups: comp.unix.questions Subject: Re: Problems with a munged tar tape Message-ID: <1893@ulysses.homer.nj.att.com> Date: Mon, 2-Feb-87 21:37:21 EST Article-I.D.: ulysses.1893 Posted: Mon Feb 2 21:37:21 1987 Date-Received: Tue, 3-Feb-87 22:42:00 EST References: <24358@rochester.ARPA> Organization: AT&T Bell Laboratories, Murray Hill Lines: 29 Summary: you may have to write a 6250 tape mark In article <24358@rochester.ARPA>, ken@rochester.ARPA (SKY) writes: > I would have mailed but I can't figure out your address. > > Try using mt to skip one file, then dd. It looks like somebody > overwrote the first part of it. Some tape controllers have automatic > density sensing so if you do any reads on it at all it will think a > 1600 bpi tape was mounted. > > Ken If the 6250 BPI tape really had some crud written at 1600, you will probably have to write a new tape mark at 6250. The tape drives I have seen not only sense density, but refuse to change density from that of the first record. Since the density is encoded in a "density id burst" that preceeds the first record, a file skip won't help. Try : > /dev/high-density-auto-rewind-name (assuming [bk]sh syntax). The next trick will be to convince tar to read the munged file. I don't have any good solution to that one. If all else fails, dump the raw tar file onto a disk then edit out the tar headers. -- Griff Smith AT&T (Bell Laboratories), Murray Hill Phone: 1-201-582-7736 UUCP: {allegra|ihnp4}!ulysses!ggs Internet: ggs@ulysses.uucp