1. A method of increasing storage capacity of a disk drive comprising: mapping defective and non-defective fractional sectors of one or more data sectors by way of storing a table of entries which specifies locations of said defective and non-defective fractional sectors into a memory; using said non-defective fractional sectors of said one or more data sectors to perform a read or write operation, wherein the size of each of said defective and non-defective fractional sectors is determined using an expected defect size.