As part of the Red Book is described how to implement and perform error detection and correction when reading a CDG disc. Since a CDG disc can get scratched and in other ways return incorrect or incomplete data, it makes sense to be able to detect such a situation and possibly correct it. The error detection and correction scheme described in the Red Book is based on a Reed Solomon algorithm. Briefly explained the Reed Solomon algorithm is based on the calculation of parity elements which are embedded in the data stream. The number of parity elements decides how many errors can be corrected; the Reed Solomon algorithm will almost always be able to detect errors, but to identify the bad elements and correct them requires a minimum number of parity elements. For more details about the Reed Solomon algorithm and how it can be implemented please refer to this Wikipedia article.
Some CD (and DVD) drives on the market supports error detection and correction implemented in the hardware. Mostly used are some of the Plextor models. For software programs that do not implement error detection and correction it is vital that the drive used to rip CDG discs supports it in order to get error free tracks. With CDGFix 3 Super however you have much more flexibility in selecting a CD drive. This is because CDGFix 3 Super implements Reed Solomon error detection and correction in software. If the CD drive used supports error detection and correction it is used, otherwise the software implementation kicks in to do the work. The only requirement to the CD drive is that it supports returning the raw sub channel data that holds the CDG stream, which most CD drives do.