E Errors, Level 2
E12, E22, and E32
E12 means one bad symbol was corrected in the C2 stage and E22 means two bad
symbols were corrected in the C2 stage. E32 means that there were three or more bad
symbols in one block at the C2 stage, and therefore this error in not correctable.
Although it is possible under some circumstances to correct up to four bad symbols at the second stage, not all players can do this. Until recently, most players could only correct two bad symbols at the C2 stage. For these players, E32 would be uncorrectable. In order to have a high probability of a disc working in any drive, we consider E32 an uncorrectable error, even though some drives may be able to correct it.
This is also the rationale for not allowing E22 or E32 errors on a CD-ROM. The earliest
generation of CD players could only correct one bad symbol at the C2 stage. As a result, an E22 error (two bad symbols at the second stage) would be uncorrectable on these drives. In order to have the highest confidence in a data disc, it should have no E22 or E32 errors. Also, keep in mind that this requirement is for new discs, as made. Obviously, the quality will degrade with use and age. Making discs with E22 or E32 errors does not leave adequate margin for future degradation. This is not an onerous requirement, because with modern equipment, there is no reason to make discs with E22 or E32 errors.