It looks like the header is OK having known values in at least the beginning.
Other corruption case may show only chr(0), and then it is unrepearable for sure. By the way, this case prompted me to start with yrecover utility.

>Yuri,
>
>Under what conditions will your snip of code tell you that the
>dbc is not repairable?? Have you ever encountered a condition
>of that sort??
>
>Thanks,
>Dan