Defect skipping mechanism for disk drives.

摘要

A novel technique for skipping defects on a magnetic or writable optical disk is described. The technique includes a sector format comprising a header (24) and data area (28), wherein the data area can include one or more "bad areas" (108, 116) which will be skipped when data is being written to or read from the sector. The bad areas are variable in size and may be located anywhere in the data area, including in an EDAC. The header includes a defect descriptor (48) comprising a defect pointer (70, 72) for each of the bad areas supported. Each defect pointer contains a value (74, 78) indicating the number of bytes in the good data area (106, 114) preceding the bad area pointed to by the defect pointer, and a value (76, 80) indicating the number of bytes in the bad area. The value indicating the number of bytes in a good area is set to a value indicating a number of bytes as least as large as the sector size if there is no subsequent bad area in the data area. A method for reading or writing data to a sector formatted as above is also described. A method for formatting a disk as above is described as well.