SCSI-2
The raw defect rate is typically higher for optical medium than for
magnetic medium. Data is usually recovered through the use of
sophisticated error correction algorithms. The level of error
correction used for data recovery is often can be selected. However,
many write-once devices have a minimum level that is always used and
cannot be de-selected through the error recovery mode parameter.
Control of the error correction algorithms and level of correction is
vendor-specific.
Defect management on write-once devices is usually vendor-specific.
However, there are standards for some types of write-once media that
specify defect management techniques. These standards, where they
exist, may supersede the implementation requirements pertaining to
error and defect reporting in this International Standard.