A storage media includes a plurality of servo sectors with embedded servo patterns characterized by one or more servo pattern parameters. Each of the servo sectors has a servo pattern parameter based on a separation between read sensors of a transducer head reading the servo sector.

According to one embodiment, a magnetic disk device includes a disk having first servo data including a first preamble, a first servo mark, a first gray code, first burst data, and second burst data written after the first burst data, a head including a write head that writes data to the disk and a first read head and a second read head that read data from the disk, and a controller that reads the second burst data using the first read head and the second read head and calculates a servo demodulation position when the first servo data is servo-read without reading the first burst data in a short servo mode in which the first preamble, the first servo mark, and the first gray code are not read.

According to one embodiment, a magnetic disk device includes a disk having a first sector including first servo data, first user data, and first correction information used to correct a data error, a head that writes data to the disk and that reads data from the disk, and a controller that changes, according to a first defect length of a defect generated in the first sector in a circumferential direction of the disk, a first sector length of the first sector in the circumferential direction.

Systems and methods are disclosed for phase locking of a clock. In some embodiments, a phase locked clock (PLC) module can phase-lock a write clock to a media written with multiple servo zones of different frequencies. In some implementations, this can be utilized to perform a self-servo write (SSW) of a disc surface within a hard disc drive (HDD). A PLC module can perform a method of writing with a single frequency phase coherently while a read element passes over servo zones with different frequencies. While the PLC module can perform such methods for a SSW process, the methods can also be utilized for other applications that can benefit from writing with a single frequency phase coherently based on servo zones with different frequencies.

A data storage device is disclosed comprising a head actuated over a disk comprising a plurality of servo sectors defining a plurality of data tracks, wherein each servo sector comprises a track ID followed by a sync mark followed by at least one servo burst, and a first servo sector does not include a preamble. During a read operation, a servo gate is opened in order to read the track ID, the sync mark, and the servo burst of the first servo sector. During a write operation, the servo gate is opened in order to miss reading at least part of the track ID of the first servo sector so as to reduce a write gap preceding the first servo sector.

A magnetic disk device includes a plurality of magnetic heads, a storage unit that stores a table storing, for each of the magnetic heads, a track skew value obtained by adding a head shared value and a head unique value, and a control unit that reads out the track skew value corresponding to one of the magnetic heads to be operated from the table and performs seek control.

According to one embodiment, a magnetic disk device includes a disk having first servo data including a first preamble, a first servo mark, a first gray code, first burst data, and second burst data written after the first burst data, a head including a write head that writes data to the disk and a first read head and a second read head that read data from the disk, and a controller that reads the second burst data using the first read head and the second read head and calculates a servo demodulation position when the first servo data is servo-read without reading the first burst data in a short servo mode in which the first preamble, the first servo mark, and the first gray code are not read.

A data storage device is disclosed comprising a head actuated over a disk comprising a plurality of servo sectors defining a plurality of data tracks, wherein each servo sector comprises a track ID followed by a sync mark followed by at least one servo burst, and a first servo sector does not include a preamble. During a read operation, a servo gate is opened in order to read the track ID, the sync mark, and the servo burst of the first servo sector. During a write operation, the servo gate is opened in order to miss reading at least part of the track ID of the first servo sector so as to reduce a write gap preceding the first servo sector.

A data storage device is disclosed comprising at least one head configured to access a magnetic tape comprising a plurality of servo frames each comprising a plurality of servo bursts, wherein each servo burst comprises a plurality of servo stripes. The servo stripes in a first servo burst are read using the head to generate a first read signal that is processed using a first matched filter matched to the first servo burst in order to generate an average time stamp for the servo stripes in the first servo burst. A position error signal (PES) is generated based on the average time stamp of the first servo burst, and the head is positioned relative to the magnetic tape based on the PES.

According to one embodiment, a first storage area and a second storage area in which a plurality of tracks are set are provided in a radial direction of a magnetic disk. A plurality of post codes corresponding to the second storage area is stored in the first storage area. A controller controls first processing of reading a plurality of post codes from the first storage area and writing the plurality of read post codes in servo area of the second storage area. In the first processing, the controller controls both second processing and third processing in a state where a write head is located on a first track. The second processing is processing of writing a post code among the plurality of read post codes in a servo area. The third processing is processing of writing user data in a data area or reading user data from a data area.