MAGNETIC DISK DEVICE

PURPOSE:To shorten a time to record and reproduce data after a head is sought to a target track by providing two servo sector areas for positioning the head on one surface of a magnetic disk. CONSTITUTION:The data track TR is formed concentrically on the magnetic disk 1 at a prescribed pitch an index position IX1 of a reference on a circumference and an index position IX2 separated by a constant angle with respect to the position are set, the servo sector areas SS1, SS2 are formed in the positions IX1, IX2, respectively and further, servo burst patterns A, B are recorded on the areas SS1 and SS2. According to the seek command from a host side, a control part 25 detects 26 a servo burst signal corresponding to the patterns A, B when the level deviation of respective signals La, Lb is above an allowable value, the position of the magnetic head 2 is corrected through a control part 28 and when the respective level deviations are below the allowable value, data from a reading/writing circuit 24 is transferred to an external interface circuit 27.