Read head characteristic pre-detection
Implementations disclosed herein provide a method comprising applying voltage to a read head during an unload state, detecting characteristic read head data, and storing the detected characteristic read head data in a buffer. In another implementation, the method further comprises performing a read retry operation in response to a read failure, reading the detected characteristic read head data from the buffer, determining if the detected characteristic read head data meets a threshold for a first predetermined criterion, performing a correction operation if the threshold for the first the first predetermined criterion is met, determining whether a media sector is read successfully, and ending the read retry operation if the media sector is read successfully.
1. A method comprising:
applying voltage to a read head during an unload state;
detecting characteristic read head data responsive to the applied voltage; and
storing the detected characteristic read head data in a buffer.
2. The method of claim 1 , further comprising:
performing a read retry operation in response to a read failure;
reading the detected characteristic read head data from the buffer;
determining if the detected characteristic read head data meets a threshold for a first predetermined criterion;
performing a correction operation if the threshold for the first predetermined criterion is met;
determining whether a media sector is read successfully; and
ending the read retry operation if the media sector is read successfully.
3. The method of claim 2 , wherein the first predetermined criterion is based on a measured instability value of the read head.
4. The method of claim 2 , wherein the first predetermined criterion is based on a measured asymmetry value of the read head.
5. The method of claim 3 , wherein the correction operation is a thermal shock operation.
6. The method of claim 4 , wherein the correction operation is an asymmetry correction operation.
7. The method of claim 2 , further comprising performing another read retry operation if the first predetermined criterion is not met.
8. The method of claim 2 , further comprising performing another read retry operation if the media sector is not read successfully.
9. A storage device, comprising:
a preamplifier configured to apply voltage to a read head during an unload state;
a detector configured to detect characteristic read head data; and
a controller configured to store the detected characteristic read head data in a buffer.
10. The storage device of claim 9 , wherein the storage device is further configured to:
perform a read retry operation in response to a read failure;
read the detected characteristic read head data from the buffer;
determine if the detected characteristic read head data meets a threshold for a first predetermined criterion;
perform a correction operation if the threshold for the first predetermined criterion is met;
determine whether a media sector is read successfully; and
end the read retry operation if the media sector is read successfully.
11. The storage device of claim 10 , wherein the first predetermined criterion is based on a measured instability value.
12. The storage device of claim 10 , wherein the first predetermined criterion is based on a measured asymmetry value.
13. The storage device of claim 10 , wherein the correction operation is a thermal shock operation.
14. The storage device of claim 10 , wherein the correction operation is an asymmetry correction operation.
15. One or more computer-readable storage media encoding computer-executable instructions for executing on a computer system a computer process that performs a correction operation based on a detected read head characteristic, the computer process comprising:
applying voltage to a read head during an unload state;
detecting characteristic read head data;
storing the detected characteristic read head data in a buffer;
performing a read retry operation in response to a read failure;
reading the detected characteristic read head data from the buffer;
determining if the detected characteristic read head data meets a threshold for a first predetermined criterion;
performing a correction operation if the threshold for the first predetermined criterion is met;
determining whether a media sector is read successfully; and
ending the read retry operation if the media sector is read successfully.
16. The one or more computer-readable storage media of claim 15 , wherein the first predetermined criterion is based on a measured instability value.
17. The one or more computer-readable storage media of claim 15 , wherein the first predetermined criterion is based on a measured asymmetry value.
18. The one or more computer-readable storage media of claim 15 , wherein the correction operation is a thermal shock operation.
19. The one or more computer-readable storage media of claim 15 , wherein the correction operation is an asymmetry correction operation.
20. The one or more computer-readable storage media of claim 18 , wherein the computer process further comprises performing another read retry operation if the first predetermined criterion is not met.