No problem. I appreciate the response. You are correct, I really don't know the format. I'll try the dd idea and see what happens. I was counting on the file marks being there so I figured I could walk through the marks and see what is there but I didn't realize about asf. Thanks
> > From: Richard Fish <[EMAIL PROTECTED]> > Date: 2006/02/07 Tue AM 10:20:09 EST > To: gentoo-user@lists.gentoo.org > Subject: Re: [gentoo-user] Getting at archives on tapes > > On 2/5/06, Brett I. Holcomb <[EMAIL PROTECTED]> wrote: > > Okay, I think I figured out what they are doing. They have a bunch of files > > for the labels. If I move forward using asf n where n is a number from 1-n > > I > > can walk through the label files. They take two files/label file so I go > > from 1 to 3 to 5 .... > > > > How do I get to this file to untar it? What I have is this when I do tar > > -tvf /dev/tape0n. > > > > -rw-rw---- 0/0 1994 2004-11-20 20:56:25 /tmp/fs_95.lbl > > > > Thanks. > > Sorry for the slow response on this. > > It sounds like you don't really know the exact contents of the tapes, > so I think you should do something like: > > # dd if=/dev/tape0n of=archive1 bs=10k > # dd if=/dev/tape0n of=archive2 bs=10k > ... > # dd if=/dev/tape0n of=archiveN bs=10k > > This should give you a dump of all of the data on the tape, and then > you can analyze it in more detail. You might have to fiddle with the > bs= value above though. > > For some background info, tape devices generally write file marks > between archives. So as long as you are using the no-rewind tape > device and reading the full archive, you can usually just read them > one after the other. The mt fsf command is mostly useful for skipping > over archives. > > However, tape devices are not very consistent. Sometimes if you read > just part of an archive and close it, the tape will automatically move > to the next file mark. Other devices will require an mt fsf command > to get to the next file mark. > > The asf command sometimes works, and sometimes doesn't. rewind and > fsf is the safest method. > > -Richard > > > > > > > > On Sunday February 5 2006 23:36, Richard Fish wrote: > > > On 2/5/06, Brett I. Holcomb <[EMAIL PROTECTED]> wrote: > > > > I have a scsi tape library and a backup program that creates datasets of > > > > tar files on the tapes. I gather each dataset is a tar file. I would > > > > like to be able to access each of these tar files. At this point I can > > > > tar -tvf /dev/tape0 and see the file that contains the tape label. But > > > > I > > > > can't get beyond that. I've tried skipping to the next file, records, > > > > set mark using mt with no luck. > > > > > > mt is the correct command, but you need to make sure you are using a > > > no-rewind tape device (ntape or nst0). Otherwise you will end up > > > seeking to the next file, closing the file descriptor, which causes > > > the driver to rewind the tape. > > > > > > -Richard > > > > -- > > > > Brett I. Holcomb > > -- > > gentoo-user@gentoo.org mailing list > > > > > > -- > gentoo-user@gentoo.org mailing list > > -- gentoo-user@gentoo.org mailing list
