Disk drive including a delay circuit to provide a delayed reset signal

1. A disk drive comprising:

a head to perform write and read operations to and from a disk;

a disk controller coupled to the head to control the write and read operations performed by the head;

a power loss detection circuit to detect a power loss and to generate a reset signal in response to the power loss;

a reset power line coupled to the disk controller and the power loss detection circuit to provide a non-delayed reset signal to the disk controller; and

a delay circuit coupled to the reset power line, wherein the delay circuit delays the reset signal to provide a delayed reset signal.

2. The disk drive of claim 1 , wherein the disk controller interprets the non-delayed reset signal as a power loss warning signal.

3. The disk drive of claim 1 , wherein the disk controller responsive to the non-delayed reset signal from the reset power line terminates an active write operation performed by the head at a data sector boundary.

4. The disk drive of claim 3 , wherein the data sector boundary is a next data sector boundary of the active write operation occurring after the non-delayed reset signal is received.

5. The disk drive of claim 3 , wherein terminating the active write operation performed by the head at the data sector boundary avoids a write-splice on the data sector.

6. The disk drive of claim 1 , wherein the disk controller enters a reset condition and a controlled shutdown in response to the delayed reset signal.

7. The disk drive of claim 1 , wherein the delay circuit is set at a minimum delay value to allow the disk controller to finish an active write operation at a data sector boundary.

8. The disk drive of claim 1 , wherein the delay circuit is constrained by a maximum delay value so that the active write operation is terminated before the head is moved for parking due to a controlled shutdown.

9. The disk drive of claim 1 , wherein the disk controller comprises the delay circuit.

10. The disk drive of claim 9 , wherein the delay circuit includes a gate, the gate to receive the reset signal and a not-busy signal from a disk formatter.

11. The disk drive of claim 1 , wherein the disk controller comprises a disk formatter.

12. The disk drive of claim 1 , wherein the power loss detection circuit comprises the delay circuit.

13. The disk drive of claim 1 , further comprising a disk formatter coupled to the delay circuit and the reset power line, wherein the delayed and non-delayed reset signals are received by the disk formatter.

14. The disk drive of claim 1 , further comprising an adjustment circuit to adjust the delay of the delay circuit.

15. The disk drive of claim 14 , wherein the disk formatter provides an adjustment value to the adjustment circuit based on the present location of the head in completing a writing of a data sector.

16. The disk drive of claim 1 , further comprising a disk drive power controller coupled to the disk controller, wherein the disk drive power controller comprises the power loss detection circuit.

17. The disk drive of claim 1 , wherein the delay circuit comprises a delay line.

18. A method to delay a reset signal in a disk drive comprising:

detecting a power loss;

generating a reset signal in response to the power loss;

providing a non-delayed reset signal to a disk controller of the disk drive; and

delaying the reset signal to provide a delayed reset signal.

19. The method of claim 18 , further comprising interpreting the non-delayed reset signal as a power loss warning signal.

20. The method of claim 18 , further comprising terminating an active write operation performed by a head at a data sector boundary responsive to the non-delayed reset signal.

21. The method of claim 20 , wherein the data sector boundary is a next data sector boundary of an active write operation occurring after the non-delayed reset signal is received.

22. The method of claim 20 , wherein terminating the active write operation performed by the head at the data sector boundary avoids a write-splice on the data sector.

23. The method of claim 18 , wherein, responsive to the delayed reset signal, the disk controller enters a reset condition and a controlled shutdown.

24. The method of claim 18 , further comprising delaying the reset signal to allow the disk controller to finish an active write operation at a data sector boundary.

25. A disk drive comprising:

a head to perform write and read operations to and from a disk;

a disk controller coupled to the head to control the write and read operations performed by the head;

means for detecting a power loss;

means for generating a reset signal in response to the power loss;

means for providing a non-delayed reset signal to the disk controller; and

means for delaying the reset signal to provide a delayed reset signal to the disk controller.