Surface error scanning




Optical media can predictively be scanned for errors and media deterioation well before any data becomes unreadable.

A higher rate of errors may indicates deteriorating and/or low quality media, physical damage, an unclean surface and/or media written using a defective optical drive. Those errors can be compensated by error correction to some extent.

Error scanning software includes Nero DiscSpeed, k-probe, Opti Drive Control (formerly "CD speed 2000") and DVD info Pro for Windows, and QPxTool for cross-platform.

Support of error scanning functionality varies per optical drive manufacturer and model.

Error typesedit

There are different types of error measurements, including so-called "C1", "C2" and "CU" errors on CDs, and "PI/PO (pairity inner/outer) errors" and the more critical "PI/PO failures" on DVDs. Finer-grain error measurements on CDs supported by very few optical drives are called E11, E21, E31, E21, E22, E32.

"CU" and "POF" represent uncorrectable errors on data CDs and DVDs respectievly, thus data loss, and can be a result of too many consecutive smaller errors.

Due to the weaker error correction used on Audio CDs (Red Book standard) and Video CDs (White Book standard), C2 errors already lead to data loss. However, even with C2 errors, the damage is unhearable to some extent.

Blu-Ray discs use so-called LDC (Long Distance Codes) and BIS (Burst Indication Subcodes) error parameters. According to the developer of the Opti Drive Control software, a disc can be considered healthy at an LDC error rate below 13 and BIS error rate below 15.

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