Data storage device estimating servo zone to reduce size of track address
View Patent ↗A data storage device is disclosed comprising a head actuated over a disk comprising a plurality of servo sectors defining a plurality of servo tracks. The servo tracks form a plurality of servo zones, and at least one servo sector of a servo track comprises a partial track address. A read signal generated by the head is processed to detect a current servo zone for the head, and the read signal is processed to detect the partial track address in one of the servo sectors of the current servo zone. A full track address is generated based on the detected servo zone and the detected partial track address.
1. A data storage device comprising:
a disk comprising a plurality of servo sectors defining a plurality of servo tracks, wherein:
the servo tracks form a plurality of servo zones; and
at least one servo sector of a servo track comprises a partial track address;
a head; and
control circuitry configured to:
process a read signal generated by the head to detect a current servo zone for the head;
process the read signal to detect the partial track address in one of the servo sectors of the current servo zone; and
generate a full track address based on the detected servo zone and the detected partial track address.
2. The data storage device as recited in claim 1 , wherein:
the partial track address represents a plurality of low order bits of the full track address; and
the detected servo zone represents at least one high order bit of the full track address.
3. The data storage device as recited in claim 1 , wherein:
a servo data rate of servo sectors in a first servo zone is different than a servo data rate of servo sectors in a second servo zone; and
the control circuitry is configured to detect the current servo zone for the head based on a detected data rate of the servo sectors.
4. The data storage device as recited in claim 1 , wherein:
a first servo sector of a first servo track of a first servo zone comprises a first sync mark;
a second servo sector of a second servo track of the first servo zone comprises a second sync mark different from the first sync mark; and
the control circuitry is configured to detect the current servo zone for the head based on a detected sync mark in the current servo zone.
5. The data storage device as recited in claim 3 , wherein:
a first servo sector of a first servo track of a first servo zone comprises a first sync mark;
a second servo sector of a second servo track of the first servo zone comprises a second sync mark different from the first sync mark; and
the control circuitry is configured to:
detect a sync mark in the current servo zone for the head; and
generate the full track address based on the detected servo zone, the detected sync mark, the detected partial track address.
6. The data storage device as recited in claim 5 , wherein:
the partial track address represents a plurality of low order bits of the full track address;
the detected sync mark represents at least one middle order bit of the full track address; and
the detected servo zone represents at least one high order bit of the full track address.
7. A method of operating a data storage device, the method comprising:
processing a read signal generated by a head to detect a current servo zone for a head over a disk, the disk comprising servo tracks that form a plurality of servo zones;
processing the read signal to detect a partial track address in at least one of the servo sectors of the current servo zone; and
generating a full track address based on the detected servo zone and the detected partial track address.
8. The method as recited in claim 7 , wherein:
the partial track address represents a plurality of low order bits of the full track address; and
the detected servo zone represents at least one high order bit of the full track address.
9. The method as recited in claim 7 , wherein:
a servo data rate of servo sectors in a first servo zone is different than a servo data rate of servo sectors in a second servo zone; and
the method further comprises detecting the current servo zone for the head based on a detected data rate of the servo sectors.
10. The method as recited in claim 7 , wherein:
a first servo sector of a first servo track of a first servo zone comprises a first sync mark;
a second servo sector of a second servo track of the first servo zone comprises a second sync mark different from the first sync mark; and
the method further comprises detecting the current servo zone for the head based on a detected sync mark in the current servo zone.
11. The method as recited in claim 9 , wherein:
a first servo sector of a first servo track of a first servo zone comprises a first sync mark;
a second servo sector of a second servo track of the first servo zone comprises a second sync mark different from the first sync mark; and
the method further comprises:
detecting a sync mark in the current servo zone for the head; and
generating the full track address based on the detected servo zone, the detected sync mark, the detected partial track address.
12. The method as recited in claim 11 , wherein:
the partial track address represents a plurality of low order bits of the full track address;
the detected sync mark represents at least one middle order bit of the full track address; and
the detected servo zone represents at least one high order bit of the full track address.