Directory Checksum error

[Senthilvel Kandasamy]

Hi,

I am trying to extract a tape which gives error as "Directory check sum error" & nothing more.

The tape was written from a SGI machine using regular tar command, I don't know whether that makes any difference.

I have tried the following commands
tar -xvbf 1 /dev/rmt/tape
tar -xvbf 2 /dev/rmt/tape
tar -xvbf 10 /dev/rmt/tape
tar -xvbf 20 /dev/rmt/tape
tar xv

I would appreciate if someone could let me know what I am doing wrong. Thanking you all in advance.

[Rita C Workman]

Found the following. It's from a 1995 doc, but seemed appropriate.
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Doc ID: A1327736
Tar reads the stored checksum from the tape and also uses other fields read from the tape to compute a checksum. When these checksums do not match, errors will display of this nature. The errors typically happen from backup media because the media somehow has been damaged or de-magnetized but other possibilities are listed below :

1. The tar tape might not be a tar tape at all and could be a cpio, fbackup, or some other backup utility tape.

2. The tar could have been written using the "O" option which is the pre-POSIX format and not the normal default of "N" which is the POSIX format.

3. The block factor was not the default and specified with the "b" option.

4. Verify what options were used to create the tar archive.

5. Check to make sure that tar is the current patched version for the operating system and also any kernel drivers that have been patched.

6. Do not rule out hardware. Attempt to archive off some files to a scratch tape and restore them. Make sure that the drive is performing as it normally should.

Hope it helps,
Rita