Servo information correcting method
A operation of storing a post code, which is read from each servo frame on a target track of a disk recording medium, in a memory if an on-track condition for determining that a head is controlled to be positioned on the target track is satisfied is executed. Next, a operation of using the post code, which is stored in the memory, for a correction of a demodulation position if the post code corresponding to each servo frame is stored in the memory and the on-track condition is satisfied in the correction of the demodulation position in each servo frame is executed.
1. A servo controlling method, which is used in a disk storage device, for controlling a head to be positioned on a target track by reading servo information and a post code, which indicates an eccentricity of the servo information, from each servo frame recorded on each track of a disk recording medium via the head provided in an actuator, by correcting a demodulation position demodulated from the servo information with the post code, and by driving the actuator on the basis of the corrected demodulation position, comprising:
storing the post code, which is read from each servo frame on the target track of the disk recording medium, in a memory if an on-track condition for determining that the head is controlled to be positioned on the target track is satisfied; and
using the post code stored in the memory in order for a correction of the demodulation position if the post code corresponding to each servo frame is stored in the memory and the on-track condition is satisfied, in the correction of the demodulation position in each servo frame.
2. The servo information correcting method according to claim 1 , further comprising:
clearing the post code stored in the memory if the post code corresponding to each servo frame is stored in the memory and the on-track condition is not satisfied, in the correction of the demodulation position in each servo frame.
3. The servo information correcting method according to claim 1 , further comprising:
clearing all post codes that correspond to servo frames and are stored in the memory when a seek operation for a new target track starts.
4. The servo information correcting method according to claim 3 , further comprising:
once clearing all the post codes that correspond to the servo frames and are stored in the memory by once doing a seek for another target track during a retry of a data write to the disk recording medium.
5. The servo information correcting method according to claim 1 , wherein
the on-track condition is a condition for determining that the head is controlled to be positioned so that an eccentricity of the head from a center position of the target track is within a predetermined value.
6. The servo information correcting method according to claim 1 , wherein
the on-track condition is a condition for determining that the state where the head is controlled to be positioned so that an eccentricity of the head from a center position of the target track is within a predetermined value is satisfied for a predetermined number of successive servo frames.
7. The servo information correcting method according to claim 1 , wherein
the post code that corresponds to each servo frame and is stored in the memory is not cleared while the on-track condition is satisfied for the current target track even when a seek instruction for a new target track is received.
8. The servo information correcting method according to claim 1 , wherein
the operation of storing the post code in the memory is executed only after a seek operation for a data write to the disk recording medium is performed.