Abstract: a firm ware based technique related to managing defective data sector information in a disk drive. Specially, technique provides for a dynamic method by which the number of spare or served alternate sectors and their locations can be allocated in the event defective data sectors exist. One advantage of the present invention exists for certain applications where the capacity and/or configuration of the drive are configured at run time. The present invention also has the advantage of improving performance when accessing “grown” defects by allowing the block relocation information to be placed physically closer to the location of the defective blocks.