--totals in tar

[Frank Maas]

To whom it may concern,

I'm archiving files from our data acquisition 
on a dlt tape using tar. Everything works fine so far,
I'm collecting data writing them collecting more appending them
at the end of the existing archieve etc...
BUT I only get the number of bytes written the first time,
when I create the first archieve on the tape.
Whwn I'm appending more data to the archieve,
I don't get the output of --totals any more.
How can I access this information??
I'm using Linux, SUSE 6.3.
if [ $FIRST_RUN -eq 0 ]
    then
        tar -c --totals -f $DLT_DRIVE -V$TAPE_LABEL  $RUNNUMBER 2>&1 | awk
'{print  $4 >"'$WRITBYT_FILE'"}'
    else
        tar -r --totals -f $DLT_DRIVE -V$TAPE_LABEL  $RUNNUMBER 2>&1 | awk
'{print  $4 >"'$WRITBYT_FILE'"}'
fi

The first line with option -c works fine and produces
the output as documented. The second line does not
produce anything, even if not filtered by awk.
$DLT_DRIVE is /dev/st1

What am I missing???
many thanks for any hint
best regards
Frank Maas

-- 
+----------------------------------------------+
| Dr. Frank Maas                               |
| Institut fuer Kernphysik                     |
| A4 - collaboration                           |
| Parity Violation Experiment                  |
| Johannes-Gutenberg-Universitaet Mainz        |
| J.J.Becherweg 45                             |
| 55099 Mainz                                  |
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| Email: address@hidden                 |
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