Data storage device eliminating preamble from servo sectors
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.
1. A data storage device comprising:
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 for timing synchronization of a read signal;
a head actuated over the disk; and
control circuitry configured to:
during a read operation, open a servo gate in order to read the track ID, the sync mark, and the servo burst of the first servo sector; and
during a write operation, open the servo gate 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.
2. The data storage device as recited in claim 1 , wherein at least one servo burst of the first servo sector consists of a periodic sequence of magnetic transitions.
3. The data storage device as recited in claim 2 , wherein the at least one servo burst of the first servo sector consists of an amplitude based servo burst.
4. The data storage device as recited in claim 2 , wherein the at least one servo burst of the first servo sector consists of a phase based servo burst.
5. The data storage device as recited in claim 1 , wherein the control circuitry is further configured to:
read the first servo sector to generate a read signal;
sample the read signal using a disk locked clock to generate signal samples;
detect the sync mark from the signal samples and detect a phase error from the signal samples of the sync mark; and
after detecting the sync mark, detect at least part of the track ID from the signal samples and adjust the disk locked clock based on the detected phase error.
6. The data storage device as recited in claim 1 , further comprising a shock sensor configured to generate a shock signal representing a shock affecting the data storage device, wherein the control circuitry is further configured to abort the write operation when the shock signal exceeds an abort threshold.
7. The data storage device as recited in claim 6 , wherein the control circuitry is further configured to adjust the abort threshold based on a length of the track ID that is read when opening the servo gate during the write operation.
8. The data storage device of claim 1 , wherein each servo sector comprises the track ID immediately followed by the sync mark immediately followed by at least one servo burst.
9. A data storage device comprising:
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 for timing synchronization of a read signal;
a head actuated over the disk; and
control circuitry configured to:
read the first servo sector to generate a read signal;
sample the read signal using a disk locked clock to generate signal samples;
detect the sync mark from the signal samples and detect a phase error from the signal samples; and
after detecting the sync mark, detect at least part of the track ID from the signal samples and adjust the disk locked clock based on the detected phase error.
10. The data storage device as recited in claim 9 , wherein at least one servo burst of the first servo sector consists of a periodic sequence of magnetic transitions.
11. The data storage device as recited in claim 10 , wherein the at least one servo burst of the first servo sector consists of an amplitude based servo burst.
12. The data storage device as recited in claim 10 , wherein the at least one servo burst of the first servo sector consists of a phase based servo burst.
13. The data storage device as recited in claim 9 , wherein the control circuitry is further configured to:
during a read operation, open a servo gate in order to read the track ID, the sync mark, and the servo burst of the first servo sector; and
during a write operation, open the servo gate 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.
14. The data storage device as recited in claim 13 , further comprising a shock sensor configured to generate a shock signal representing a shock affecting the data storage device, wherein the control circuitry is further configured to abort the write operation when the shock signal exceeds an abort threshold.
15. The data storage device as recited in claim 14 , wherein the control circuitry is further configured to adjust the abort threshold based on a length of the track ID that is read when opening the servo gate during the write operation.
16. A data storage device comprising:
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 for timing synchronization of a read signal;
a head actuated over the disk; and
a means during a read operation for opening a servo gate in order to read the track ID, the sync mark, and the servo burst of the first servo sector; and
a means during a write operation for opening the servo gate 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.
17. The data storage device as recited in claim 16 , wherein at least one servo burst of the first servo sector consists of a periodic sequence of magnetic transitions.
18. The data storage device as recited in claim 17 , wherein the at least one servo burst of the first servo sector consists of an amplitude based servo burst.
19. The data storage device as recited in claim 17 , wherein the at least one servo burst of the first servo sector consists of a phase based servo burst.
20. The data storage device as recited in claim 16 , further comprising:
a means for reading the first servo sector to generate a read signal;
a means for sampling the read signal using a disk locked clock to generate signal samples;
a means for detecting the sync mark from the signal samples and detecting a phase error from the signal samples of the sync mark; and
after detecting the sync mark, a means for detecting at least part of the track ID from the signal samples and for adjusting the disk locked clock based on the detected phase error.