A method of and a system for efficiently using a split information stored in an unnecessary data sector, thereby reducing unnecessary data. The system includes first registers (301) respectively adapted to store MCDR values in response to a write control signal generated from a central processing unit, second registers (303) respectively coupled to the first registers (301), each second register (303) down-loading the MCDR value from the corresponding first register (301) in response to a servo sector interrupt application signal inverted by an inverter (N1), thereby generating signals indicative of an internal flag, an internal CDR value and a split sector number, a multiplexer (305) adapted to multiplex the internal flag signals from the second registers (303), thereby generating a flag signal, a counter (311) adapted to count the servo sector interrupt application signal, thereby generating a current sector number signal indicative of the number of a sector being currently accessed, a synthesizer (307) adapted to generate a CDR signal based on the split sector number signal from each second register (303), and a comparator (309) for comparing the split sector number signal from each second register (303) with the current sector number signal from the counter (311), thereby generating a sector good signal.