Waterfall method and apparatus for a data storage device read system

• US 9,251,844 B1
• Filed: 04/08/2015
• Issued: 02/02/2016
• Est. Priority Date: 06/02/2014
• Status: Active Grant

• Current Assignee: Western Digital Technologies Incorporated (Western Digital Corporation)
• Original Assignee: Western Digital Technologies Incorporated (Western Digital Corporation)
• Inventors: Wheelock, David W., Dahandeh, Shafa
• Primary Examiner(s): HINDI, NABIL Z
• Application Number:
  US14/682,048
• Time in Patent Office: 300 Days
• Field of Search: 360/53, 360/31, 360/46, 360/97.12, 324/210, 296/030.9
• US Class Current: 1/1
• CPC Class Codes: G11B 20/10009 Improvement or modification of read or write signals
• CPC Class Codes: G11B 20/10018 analog processing for digital recording or reproduction G11B20/10037 - G11B20/10481 take precedence
• CPC Class Codes: G11B 20/18 Error detection or correction; Testing , e.g. of drop-outs
• CPC Class Codes: G11B 5/2652 with more than one gap simultaneously operative with controlled single gap G11B5/245
• CPC Class Codes: G11B 5/3196 of thin magnetic films, e.g. functional testing of the transducing properties G11B5/455 takes precedence
• CPC Class Codes: G11B 5/455 Arrangements for functional testing of heads; Measuring arrangements for heads

Abstract

A waterfall manufacturing process and apparatus are described for a data storage device. In an aspect, a determination is made during manufacturing of a magnetic storage medium reader system whether a first reader system provides less than a predetermined performance or is nonfunctioning. The reader system includes at least the first reader system and a second reader system with reader elements on the same head. When the first reader system is determined to provide less than the predetermined performance or is nonfunctioning, the reader system is reconfigured during the manufacturing to utilize the second reader system, but not utilize the first reader system, to read the magnetic storage medium. Alternatively, the reader system is reconfigured during manufacturing to read the magnetic storage medium at less than the predetermined performance, or the reader system is situated with a different data storage device configured to function with less than the predetermined performance.

Claims

1. A magnetic storage medium reader system for a data storage device, comprising:

at least a first reader system and a second reader system, the first reader system including a first reader element, and the second reader system including a second reader element;

a first head including the first reader element and the second reader element; and

control circuitry reconfigured during manufacturing of the magnetic storage medium reader system to cause the second reader system, but not the first reader system, to read a magnetic storage medium, the first reader system determined during the manufacturing to provide less than a predetermined performance or to be nonfunctioning.

2. The magnetic storage medium reader system of claim 1, wherein the second reader system is utilized with a non-two-dimensional magnetic recording (TDMR) data storage device.

3. The magnetic storage medium reader system of claim 1, further comprising a third reader system to read the magnetic storage medium, wherein the second reader system and the third reader system are utilized with a two-dimensional magnetic recording (TDMR) data storage device.

4. The magnetic storage medium reader system of claim 1, wherein the magnetic storage medium reader system is reconfigured to at least one of:

read at a track per inch (TPI) data density that is less than if the first reader system provided at least the predetermined performance and was additionally utilized, and

provide a read signal at a signal to noise ratio (SNR) that is less than if the first reader system provided at least the predetermined performance and was additionally utilized.

5. The magnetic storage medium reader system of claim 1, wherein:

utilizing the second reader system to read the magnetic storage medium comprises utilizing one portion or more than one portion of the second reader system to read the magnetic storage medium; and

not utilizing the first reader system to read the magnetic storage medium comprises not utilizing one portion or more than one portion of the first reader system.

6. A method for manufacturing a data storage device, comprising:

determining during manufacturing of a magnetic storage medium reader system, including at least a first reader system and a second reader system, whether the first reader system provides less than a predetermined performance or is nonfunctioning, wherein the first reader system includes a first reader element, and the second reader system includes a second reader element, and wherein a first head includes both the first reader element and the second reader element; and

reconfiguring the magnetic storage medium reader system during the manufacturing to utilize the second reader system, but not utilize the first reader system, to read the magnetic storage medium, when the first reader system is determined during the manufacturing to provide the less than the predetermined performance or is nonfunctioning.

7. The method of claim 6, wherein the manufacturing is manufacturing of a magnetic storage medium reader system that includes a two-dimensional magnetic recording (TDMR) head, the method further comprising utilizing the second reader system with a non-TDMR data storage device, rather than with the TDMR data storage device, when the first reader system is determined to provide the less than the predetermined performance or is nonfunctioning.

8. The method of claim 6, further comprising utilizing the second reader system with a non-two-dimensional magnetic recording (TDMR) data storage device, when the first reader system is determined to provide the less than the predetermined performance or is nonfunctioning.

9. The method of claim 6, further comprising utilizing the second reader system and a third reader system with a two-dimensional magnetic recording (TDMR) data storage device, wherein the magnetic storage medium reader system further includes the third reader system.

10. The method of claim 6, further comprising reconfiguring the magnetic storage medium reader system to at least one of:

read at a track per inch (TPI) data density that is less than if the first reader system provided at least the predetermined performance and was additionally utilized, and

provide a read signal at a signal to noise ratio (SNR) that is less than if the first reader system provided at least the predetermined performance and was additionally utilized.

11. The method of claim 6, wherein the second reader system includes the second reader element and a second read channel, the second reader system structured such that when a second reader element signal is created, the second reader element signal travels from the second reader element to the second read channel;

and wherein the first reader system includes the first reader element and a first read channel.

12. The method of claim 6, wherein:

utilizing the second reader system to read the magnetic storage medium comprises utilizing one portion or more than one portion of the second reader system to read the magnetic storage medium; and

not utilizing the first reader system to read the magnetic storage medium comprises not utilizing one portion or more than one portion of the first reader system.

13. The method of claim 6, wherein not utilizing the first reader system comprises including at least one component of the first reader system with the magnetic storage medium reader system, but not utilizing a signal from the first reader system.

14. The method of claim 6, further comprising:

determining during the manufacturing of the magnetic storage medium reader system whether a third reader system provides less than the predetermined performance or is nonfunctioning, wherein the third reader system includes a third reader element, and wherein the first head further includes the third reader element; and

reconfiguring the magnetic storage medium reader system during the manufacturing to utilize the second reader system, but not utilize the third reader system, to read the magnetic storage medium, when the third reader system is determined during the manufacturing to provide the less than the predetermined performance or is nonfunctioning.

15. The method of claim 6, wherein reconfiguring the magnetic storage medium reader system during the manufacturing to utilize the second reader system comprises configuring the second reader element to reposition, during reading of a target track, from offset of the centerline of the target track to centerline of the target track.

16. A method for a data storage device, comprising:

determining during manufacturing of a magnetic storage medium reader system, including at least a first reader system and a second reader system, whether the first reader system provides less than a predetermined performance, wherein the first reader system includes a first reader element, and the second reader system includes a second reader element, and wherein a first head includes both the first reader element and the second reader element;

retaining the first reader system when the first reader system is determined to provide the less than the predetermined performance; and

reconfiguring the magnetic storage medium reader system to read the magnetic storage medium at the less than the predetermined performance, or situating the magnetic storage medium reader system with an alternative data storage device configured to function with the less than the predetermined performance.

17. The method of claim 16, wherein the manufacturing is manufacturing of a magnetic storage medium reader system that includes a two-dimensional magnetic recording (TDMR) head, the method further comprising situating the first reader system and the second reader system with a non-TDMR data storage device, rather than with the TDMR data storage device, when the first reader system is determined to provide the less than the predetermined performance.

18. The method of claim 16, further comprising situating the first reader system and the second reader system with a non-two-dimensional magnetic recording (TDMR) data storage device, when the first reader system is determined to provide the less than the predetermined performance.

19. The method of claim 16, further comprising situating the first reader system, the second reader system, and a third reader system with a two-dimensional magnetic recording (TDMR) data storage device, wherein the magnetic storage medium reader system further includes the third reader system.

20. The method of claim 16, further comprising reconfiguring the magnetic storage medium reader system to at least one of:

read at a track per inch (TPI) data density that is less than if the first reader system provided at least the predetermined performance, and

provide a read signal at a signal to noise ratio (SNR) that is less than if the first reader system provided at least the predetermined performance.