Skip list management for a write-once optical disk

Abstract

A method and system for managing a plurality of defects that may cause an error during a write operation in a write-once data storage disk is provided. A host system sends a write command to a disk drive that contains the storage disk. The process detects any errors that may occur during the write operation. When an error is detected, a 'skip list' containing the addresses of physical sectors on the disk that are to be skipped during a read operation is updated, the write operation is suspended, and the process attempts to rewrite the data in another sector. If the rewrite is performed successfully, the write operation continues. Otherwise, the write operation is terminated and the host device is notified. While the disk drive is operative, the skip list is preferably maintained in a buffer memory, but periodically the entries in the skip list are copied to the disk for permanent storage. Before a read operation begins, the skip list is copied from the disk to the memory. When a file is read from the disk, any 'skip sectors' that are encompassed within the file are skipped (i.e., the data in those sectors is not read). The method of this invention is particularly useful in supplementing an error correction code, which typically has difficulty dealing with errors of longer duration.