Hi.

If i have a dds4-tape that contains the backup done by a 3rd party
backup software, i have problems with doing a tar -tvf. The error
message that i get is "some checksum error"

My understanding is that tar-tvf is only for either the os backup tools
or if do a tar -cvf. since the 3rd party backup software is different,
hence i am not able to do so.

Please advise.

On 2005-05-04, hosea.basis@gmail.com <hosea.basis@gmail.com> wrote:
>
> If i have a dds4-tape that contains the backup done by a 3rd party
> backup software, i have problems with doing a tar -tvf. The error
> message that i get is "some checksum error"
>
> My understanding is that tar-tvf is only for either the os backup tools
> or if do a tar -cvf. since the 3rd party backup software is different,
> hence i am not able to do so.
>
> Please advise.

Not much to advise on... You can only use tar to read a backup if it
was done using tar. There are plenty of backup mechanisms: cpio, tar
dump/restsore, fbackup/frestore without even mentioning the commercial
backup mechanisms.

Readers' digest answer: You can read a backup tape with the same
utility that created it.

Doug

hosea.basis@gmail.com wrote:
> Hi.
>
> If i have a dds4-tape that contains the backup done by a 3rd party
> backup software, i have problems with doing a tar -tvf. The error
> message that i get is "some checksum error"

Probably "directory checksum error".

> My understanding is that tar-tvf is only for either the os backup tools
> or if do a tar -cvf. since the 3rd party backup software is different,
> hence i am not able to do so.
>
> Please advise.

Adding to Doug's advice:

Do

dd if=/dev/rmt/0mn of=/tmp/record bs=100k count=1
ll /tmp/record
file /tmp/record
rm /tmp/record

and report the results.

The dd(1) and ll(1) commands are used to determine the record size
(and incorrect record size can give a "directory checksum error" from
tar(1)).

The file(1) command is used to verify that this is indeed a tar(1)
tape and not a tape made by some other utility (like the ones Doug
mentioned).