HELP -- RESUMING TAR AFTER AN ERROR

[Andreas Borchert]

Gary Crowell writes:

>     We have a  CONVEX  C-1,  running  8.0  convexOS.   Recently, I was
> reading a TAR tape  when  it  experienced  an  error and all the files
> after the error were lost.  I  would like any utility that will notify
> me :
> 
>     -   on what file, TAR experienced the error and [more importantly]

Call tar with verbose option (v). tar prints the filename to be extracted
before copying it.

>     -   allow me to resume TAR AFTER the error causing file.

If it is a media error (i.e. you have a corrupted tape and you see some
system errors on /dev/console) dd will help in some circumstances:

   dd if=/dev/your-raw-tape-device ibs=... conv=noerror |
   tar xvf -

ibs is the input block size (usually 10k for magtapes and 63k for cartridge
tapes). Add B to the options if your tar-version supports this
(sometimes necessary when tar reads from a pipe).

If tar detects directory checksum errors you lose if you do not have
a tar-version which supports the i-option (ignore checksum errors).

Andreas Borchert
--
borchert at mathematik.uni-ulm.de