Moreover, looking to the detailed view of the right half of the optical disk 602, a number of high failure rate regions have been identified. Specifically, a high failure rate region has been identified at an outer diameter of each of the storage layers 604, 606, 608, in addition to a high failure rate region being identified at the surface of the optical disk 602 along storage layer 608. Each of these high failure rate regions have also been identified by the arrowed lines which extend to the specific unit addresses (physical addresses) that correspond to the optical disk 602.

Because these high failure rate regions are located at different physical locations along the various storage layers 604, 606, 608 of the optical disk 602, more than one of the high failure rate regions may be included in a given erasure code stripe that is formed using the optical disk 602 without implementing any mapping to virtual addresses. However, by carefully selecting strips from the optical disk 602, organizing them such that the high failure rate regions are combined, and mapping the respective unit addresses to virtual addresses as illustrated, an erasure code stripe which includes at most one strip from the high failure rate region of the respective storage unit may desirably be formed. A number of these mapping relationships are represented by the arrows that extend between unit addresses and virtual addresses. For example, unit address “stripe q” is mapped to virtual address “stripe q′”, while unit address “stripe p” is mapped to virtual address “stripe p′”.