Synchronous writing with timing error detection in bit patterned media disk drives
View Patent ↗A hard disk drive that includes a head that is coupled to a disk. The disk drive further includes a comparator circuit that is coupled to the head. The comparator circuit receives a synchronization signal and a write clock. The comparator generates a write error signal if a comparison of the synchronization and write clock signals exceeds a threshold. The write error signal can inhibit a write operation or cause a rewrite of data.
1. A hard disk drive, comprising:
a disk;
a head having a heater element that is coupled to said disk; and
a comparator circuit that is coupled to said head with the heater element, said comparator circuit receives a synchronization signal and a write clock and generates a write error signal only if a comparison of said synchronization signal and said write clock exceeds a threshold, said comparator circuit generates an error signal and said write clock is a function of said error signal.
2. The disk drive of claim 1 , wherein said write error signal inhibits a write operation.
3. The disk drive of claim 1 , wherein said write error signal causes a rewrite operation.
4. The disk drive of claim 1 , wherein said disk is a bit patterned media.
5. The disk drive of claim 1 , wherein said comparator circuit includes a clock counter that counts a number of clock signals between at least two synchronization signals and generates said write error signal if a difference between said number of counted clock signals and an anticipated number of clock signals exceeds a threshold.
6. A hard disk drive, comprising:
a disk;
a head having a heater element is coupled to said disk; and,
circuit means for receiving a synchronization signal and a write clock and generating a write error signal only if a comparison of said synchronization signal and said write clock exceeds a threshold and for generating an error signal and said write clock is a function of said error signal.
7. The disk drive of claim 6 , wherein said write error signal inhibits a write operation.
8. The disk drive of claim 6 , wherein said write error signal causes a rewrite operation.
9. The disk drive of claim 6 , wherein said disk is a bit patterned media.
10. The disk drive of claim 6 , further comprising counter means for counting a number of clock signals between at least two synchronization signals and generating said write error signal if a difference between said number of counted clock signals and an anticipated number of clock signals exceeds a threshold.
11. A method for detecting contact between a head and a disk of a hard disk drive, comprising:
providing a synchronization signal from a head with a heater element coupled to a disk;
providing a write clock;
comparing the synchronization signal and the write clock;
generating a frequency/phase error signal from the comparison of the synchronization signal and the write clock;
generating a write error signal only if the frequency/phase error signal exceeds a threshold, and,
adjusting the write clock as a function of the frequency/phase error signal.
12. The method of claim 11 , further comprising inhibiting a write operation.
13. The method of claim 11 , further comprising initiating a rewrite operation.
14. The method of claim 11 , wherein the disk is a bit patterned media.
15. The method of claim 11 , further comprising counting a number of clock signals between at least two synchronization signals and generating the write error signal if a difference between the number of counted clock and an anticipated number of clock signals exceeds a threshold.