SERVO PATTERN WRITING METHOD

PURPOSE:To eliminate a rotation wait time and to speed up operation by arranging index data at an address position shifted from the start address of servo pattern data and starting comparison with verification data corresponding to the position. CONSTITUTION:An MPU1 writes servo pattern and verification data in a servo pattern memory 2 while specifying addresses by an address counter 9, and then reads out servo patterns successively to write them on a servo disk 6 by a servo head 5 through a write circuit 3 and an R/W amplifier 4. A read verifying circuit 7, on the other hand, compares read data from the amplifier 4 with the verification data from the memory 2. At this time, the verification data is read out of an address (n) and an offset value (n) is outputted from an address counter offset circuit 9 to the counter 8 only in read verification processing. Then, the circuit 7 compares the verification data with the servo pattern data to inform the MPU1 of whether an error occurs or not.