Method of screening hard disk drive

• US 7,123,428 B2
• Filed: 09/07/2004
• Issued: 10/17/2006
• Est. Priority Date: 09/09/2003
• Status: Expired due to Fees

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kim, Jong-yoon, Yeo, Chang-dong
• Primary Examiner(s): WONG, KIN C
• Application Number:
  US10/934,364
• Publication Number:
  US 20050052768A1
• Time in Patent Office: 770 Days
• Field of Search: None
• US Class Current: 360/31
• CPC Class Codes: G11B 2220/2516 Hard disks
• CPC Class Codes: G11B 27/36 Monitoring, i.e. supervising the progress of recording or reproducing for digital recording G11B20/00 and s.gr.; for monitoring, testing or measuring of TV recorders of the type covered by H04N5/76 and subgroups, see H04N17/06
• CPC Class Codes: G11B 5/455 Arrangements for functional testing of heads; Measuring arrangements for heads

Abstract

A method of screening a hard disk drive (HDD) including: measuring one or more parameters to display read/write head performances at least two times during an HDD process; and calculating variances of the measured one or more parameters and judging whether head degradation has occurred based on the calculated variances.

Claims

1. A method of screening a hard disk drive for placement onto a market, the method comprising:

measuring one or more parameters to display read/write head performances at least two times during a hard disk drive process;

calculating variances of the measured one or more parameters and judging whether head degradation has occurred based on the calculated variances,

wherein the measuring of the one or more parameters and the calculating of the variances occur subsequent to assembly of the hard disk drive; and

determining whether the hard disk drive is qualified to be placed onto the market based on whether head degradation has occurred.

2. The method of claim 1, wherein the operation of measuring the one or more parameters to display the read/write head performances is respectively performed at least one time right after a start of the hard disk drive process, in a middle of the hard disk drive process, and right before an end of the hard disk drive process.

3. The method of claim 2, wherein the one or more parameters to display the read/write head performances includes an adaptive gain control and an asymmetry control.

4. The method of claim 3, wherein the head degradation is judged based on variances of the adaptive gain control and the asymmetry control.

5. The method of claim 1, wherein the one or more parameters to display the read/write head performances includes an adaptive gain control and an asymmetry control.

6. The method of claim 5, wherein the head degradation is judged based on variances of the adaptive gain control and the asymmetry control.

7. The method of claim 1, wherein the hard disk drive is determined to be qualified to be placed onto the market when the calculated variances are less than preset values, which indicates that there is no head degradation.

8. The method of claim 1, wherein the hard disk drive is determined not to be qualified to be placed onto the market when the calculated variances are larger than preset values, which indicates that the head has degraded or has the increased likelihood of degradation.

18. The method of claim 3, wherein the hard disk drive is determined to be qualified to be placed onto the market when the calculated variances are larger than preset values, which indicates that the head has degraded or has the increased likelihood of degradation.

9. A method of screening a hard disk drive for placement onto a market, the method comprising:

measuring one or more parameters to display read/write head performances at least two times during a hard disk drive process;

calculating variances of the measured one or more parameters and judging whether head degradation has occurred based on the calculated variances, and

determining whether the hard disk drive is qualified to be placed onto the market based on whether head degradation has occurred,

wherein the hard disk drive process includes an operation of optimizing performance characteristics of the hard disk drive and an operation of verifying read/write performances.

10. The method of claim 9, wherein the operation of optimizing the performance characteristics of the hard disk drive includes at least one of a servo calibrating operation, a channel optimizing operation, or a printed circuit board assembly checking operation.

11. The method of claim 9, wherein the operation of measuring the one or more parameters to display the read/write head performances is performed at least one time in the operation of optimizing the performance characteristics of the hard disk drive.

12. The method of claim 11, wherein the one or more parameters to display the read/write head performances includes an adaptive gain control and an asymmetry control.

13. The method of claim 12, wherein the head degradation is judged based on variances of the adaptive gain control and the asymmetry control.

14. The method of claim 9, wherein the operation of measuring the one, or more parameters to display the head read/write performances is performed at least one time in the operation of verifying the read/write performances.

15. The method of claim 14, wherein the one or more parameters to display the read/write head performances includes an adaptive gain control and an asymmetry control.

16. The method of claim 15, wherein the head degradation is judged based on variances of the adaptive gain control and the asymmetry control.

17. The method of claim 9, wherein the hard disk drive is determined to be qualified to be placed onto the market when the calculated variances are less than preset values, which indicates that there is no head degradation.

19. A method of screening a hard disk drive for placement onto a market, the method comprising:

measuring head performance parameters at least twice during a hard disk drive process;

collecting the measured head performance parameters;

determining a variance of respective measured head performance parameters, and determining that a head of the hard disk drive has degraded, or the head of the hard disk drive has an increased likelihood of degradation, using the respective variances,

wherein the measuring of the head performance parameters, and the collecting of the measured head performance parameters, and the determining of the respective variances occur subsequent to assembly of the hard disk drive; and

determining whether the hard disk drive is qualified to be placed onto the market based on whether the head has degraded or the head has an increased likelihood of degradation.

20. The method according to claim 19, wherein the measured head performance parameters comprises:

an adaptive gain control; and

an asymmetry control.

21. The method according to claim 19, wherein the measuring the head performance parameters at least twice during the hard disk drive process comprises:

measuring the head performance parameters as a first operation of the hard disk drive process.

22. The method according to claim 19, wherein the determining the variance of the respective measured head performance parameters is performed as a final operation in the hard disk drive process.

23. The method according to claim 19, wherein only the measuring head performance parameters operation is performed during the hard disk drive process.

24. The method of claim 19, wherein the hard disk drive is determined to be qualified to be placed onto the market when the calculated variances are less than preset values, which indicates that there is no head degradation.

25. The method of claim 19, wherein the hard disk drive is determined to be qualified to be placed onto the market when the calculated variances are larger than preset values, which indicates that the head has degraded or has the increased likelihood of degradation.

26. A method of screening a hard disk drive for placement onto a market, the method comprising:

measuring head performance parameters at least twice during a hard disk drive process;

collecting the measured head performance parameters;

determining a variance of respective measured head performance parameters, and determining that a head of the hard disk drive degraded, or the head of the hard disk drive has an increased likelihood of degradation, using the respective variances; and

determining whether the hard disk drive is qualified to be placed onto the market based on whether the head has degraded or the head has an increased likelihood of degradation,

wherein the measuring the head performance parameters at least twice during the hard disk drive process comprises;

measuring the head performance parameters as a first operation of the hard disk drive process,

measuring the head performance parameters subsequent to an optimizing performance characteristics of the hard disk drive operation and prior to a verifying a read/write performance operation, and

measuring the head performance parameters subsequent to the verifying the read/write performance operation.

27. The method according to claim 26, wherein the optimizing performance characteristics of the hard disk drive operation comprises:

calibrating a servo;

optimizing a channel; and

checking a printed circuit board assembly.

28. The method according to claim 27, wherein the calibrating the servo comprises:

optimizing parameters to electrically and mechanically control a read/write head position.

29. The method according to claim 28, wherein the optimizing the parameters to electrically and mechanically control the read/write head position comprises:

optimizing an MR head skew; and

optimizing a KT value, where the KT value represents a magnitude of acceleration of the MR head according to a rotational force of the MR head.

30. The method according to claim 27, wherein the optimizing the channel comprises:

optimizing a read current; and

optimizing a write current.

31. The method according to claim 27, wherein the checking the printed circuit board assembly comprises:

determining whether the printed circuit board assembly can perform required mechanical/electrical functions; and

determining whether a circuit system functions correctly.

32. The method according to claim 27, wherein the measuring the head performance parameters at least twice during the hard disk drive process further comprises:

measuring the head performance parameters subsequent to the calibrating the servo; and

;

measuring the head performance parameters subsequent to the optimizing the channel.

33. The method according to claim 26, wherein the read/write performance operation comprises:

verifying a read/write performance of each magnetic head.

34. The method according to claim 33, wherein the measuring the head performance parameters at least twice during the hard disk drive process further comprises:

measuring the head performance parameters subsequent to the verifying the read/write performance of each magnetic head.

35. The method of claim 26, wherein the hard disk drive is determined to be qualified to be placed onto the market when the calculated variances are less than preset values, which indicates that there is no head degradation.

36. The method of claim 26, wherein the hard disk drive is determined to be qualified to be placed onto the market when the calculated variances are larger than preset values, which indicates that the head has degraded or has the increased likelihood of degradation.

37. A method of screening a hard disk drive, the method comprising:

measuring head performance parameters at least twice during a hard disk drive process;

collecting the measured head performance parameters; and

determining a variance of respective measured head performance parameters, and determining that a head of the hard disk drive has degraded, or the head of the hard disk drive has an increased likelihood of degradation, using the respective variances,

wherein the measuring of the head performance parameters, and the collecting of the measured head performance parameters, and the determining of the respective variances occur subsequent to assembly of the hard disk drive,

wherein the measured head performance parameters comprises;

an adaptive gain control; and

an asymmetry control, and

wherein variance values for the adaptive gain control and the asymmetry control respectively range from about 20% to about 30%.

38. A computer readable medium encoded with processing instructions for implementing a method of screening a hard disk drive subsequent to assembly thereof for placement onto a market, performed by a computer, the method comprising:

a first set of instructions to measure head performance parameters at least twice during a hard disk drive process;

a second set of instructions to collect the measured head performance parameters;

a third set of instructions to determine, subsequent to assembly of the hard disk drive, variances of respective measured head performance parameters, and determine that a head of the hard disk drive one of has degraded, and has an increased likelihood of degradation, using the respective variances, and

a fourth set of instructions to determine whether the hard disk drive is qualified to be placed onto the market based on the determination of whether the head of the hard disk drive has degraded or has an increased likelihood of degradation.

39. The medium of claim 38, wherein the hard disk drive is determined to be qualified to be placed onto the market when the calculated variances are less than preset values, which indicates that there is no head degradation.

40. The medium of claim 38, wherein the hard disk drive is determined to be qualified to be placed onto the market when the calculated variances are larger than preset values, which indicates that the head has degraded or has the increased likelihood of degradation.