Resilient Device Copy Utility?

Hi, A while back someone wrote here (I think it was this list) about a dd-like utility that would deal with I/O errors more intelligently (or at least more flexibly). In particular, it could be made to continue on after an I/O error on the input side, skipping the output side commensurately so the output was a copy of the input with those portions that were unreadable filled with zeros. If anyone knows of such a thing, please let me know. Thanks. Randall Schulz