4.13.3 Automatic error correction

For high-end audio applications, iXOS-JUKEMAN offers an automatic error correction. This error correction takes advantage of several features of Plextor drives. To use this correction you should know about the parameters described in the following paragraphs.
A drive sometimes reads incorrect data from audio CDs in a bad status. iXOS-JUKEMAN 2.3 can try to correct these errors. The central parameter in this context is c2errs, the number of tolerated C2 errors for each block. A block is 2352 bytes, so the largest possible value for c2errs is 2352. This is the default value. Without closer inspection, the server passes on to the user whatever data the drive supplies.
Ifc2errs is smaller than 2352, the server will behave differently. Not only does it read the data but also additional information about C2 errors from the drive. If a block contains more errors than permitted by c2errs, than iXOS-JUKEMAN tries to read the block again with a lower speed level. This will be done, until the block can be read in the required quality, or until even at lowest speed too many attempts failed. In this case the server supplies the block, which contained the fewest errors of all attempts.
If the server can read many blocks correctly at first attempt, it increases the speed again by one level, up to a maximum value.
The parameter c2loop defines, how often the server tries to read a block after a failed attempt at minimum speed. The parameters c2mins and c2maxs define the lowest and the highest speed level. 0 means single speed, and each higher level means a doubling of the speed rate up to the highest rate supported by the drive. All levels above are for maximum rate. For more information, refer to the SCSI manual of the manufacturer.
If the parameter c2logs is set to 1, then the server logs each change of the speed rate in the log file. Failed attempts, to read a block in the quality defined by c2errs, will be logged depending on the parameters c2loge and c2logm. c2loge limits the log to attempts with more than c2loge C2 errors. c2logm is a bit mask. The server logs the n-th repetition only if bit n of this mask is set to 1. Each repetition after a decrease of the speed rate counts as a repetition with number 1. The first attempt for each block has the number 1. If the server logs a read attempt with too many errors, it will also log if the block could be read at a later time with an acceptable error rate.