Detecting media defects

Patent metadata

Field	Value
Publication number	US-9761272-B1
Application number	US-201615290978-A
Country	US
Kind code	B1
Filing date	Oct 11, 2016
Priority date	Oct 11, 2016
Publication date	Sep 12, 2017
Grant date	Sep 12, 2017

Abstract

A method according to one embodiment includes instructing a drive to detect a written signal burst on a magnetic tape and stop movement of the tape in response to detecting the written signal burst. A search for a defect is conducted in a location proximate to the written signal burst. An apparatus according to one embodiment includes a plurality of detector structures positioned in an array. Each of the detector structures includes a pair of conductive layers separated by an insulating material. A write transducer is aligned with each of the detector structures. A controller is configured to cause one of the write transducers to write a signal burst in response to the associated detector structure encountering a defect.

First claim

What is claimed is:

1. A method, comprising:
instructing a drive to detect a written signal burst on a magnetic tape and stop movement of the tape in response to detecting the written signal burst; and
searching a surface of the tape proximate to the written signal burst for a defect.

2. The method of claim 1 , comprising instructing the drive to move the magnetic tape to an approximate location of the defect based on linear position information previously stored in response to detecting the defect.

3. The method of claim 1 , comprising determining an approximate lateral position of the defect on the magnetic tape.

4. The method of claim 3 , wherein the approximate lateral position of the defect on the magnetic tape includes identifying a detector structure that identified the defect.

5. The method of claim 4 , wherein the approximate lateral position of the defect on the magnetic tape is determined using dark force microscopy of the detector structure that identified the defect for identifying a location of smeared material of the detector structure.

6. The method of claim 4 , wherein determining the approximate lateral position of the defect on the magnetic tape includes determining a location of material of a detector structure smeared by the defect, and measuring a distance in a cross track direction from the location of the smeared material to a projected lateral location of a datum.

7. The method of claim 1 , wherein a maximum diameter of the defect is less than 1/6000 th a width of the tape.

8. A computer program product comprising a computer readable storage medium having program instructions embodied therewith, the program instructions executable by a tape drive to cause the tape drive to:
move, by the tape drive, a magnetic tape to an approximate location of a defect based on linear position information previously stored in response to detecting the defect;
detect, by the tape drive, a written signal burst on the magnetic tape; and
stop, by the tape drive, movement of the tape in response to detecting the written signal burst.

9. The computer program product of claim 8 , comprising determining an approximate lateral position of the defect on the magnetic tape.

10. The computer program product of claim 9 , wherein the approximate lateral position of the defect on the magnetic tape includes identifying a detector structure that identified the defect.

11. The computer program product of claim 8 , comprising: program instructions executable by the tape drive to cause the tape drive to:
monitor, by the tape drive, a resistance value of each of a plurality of detector structures positioned in an array;
detect, by the tape drive, a change in a resistance value of at least one of the detector structures, for identifying an approximate location of defect on a magnetic medium; and
cause, by the tape drive, a write transducer to write a signal burst on the magnetic medium in response to detecting the change in resistance value,
wherein each of the detector structures include a pair of conductive layers separated by an insulating material.

12. An apparatus, comprising:
a plurality of detector structures positioned in an array, wherein each of the detector structures include a pair of conductive layers separated by an insulating material; and
a write transducer aligned with each of the detector structures; and
a controller configured to cause one of the write transducers to write a signal burst in response to the associated detector structure encountering a defect.

13. The apparatus of claim 12 , wherein the controller is configured to cause each write transducer to write a pattern that is specific to that write transducer.

14. The apparatus of claim 12 , wherein the controller is configured to cause a plurality of the other writer transducers to write a predefined pattern in response to the detector structure encountering a defect.

15. The apparatus of claim 12 , with a proviso that none of the detector structures include an operable reader for reading data from a magnetic medium.

16. The apparatus of claim 12 , wherein the controller is configured to monitor a resistance value of each of the detector structures; and, in response to detecting a change in a resistance value of one of the detector structures, cause the write transducer associated therewith to write a signal burst.

17. The apparatus as recited in claim 12 , comprising:
a servo reader,
wherein the controller is configured to use the servo reader to determine a position along a length of a magnetic medium that corresponds to an identified defect.

18. The apparatus as recited in claim 12 , comprising at least one electronic lapping guide.

19. The apparatus as recited in claim 12 , comprising a resistor associated with each of the detector structures, each resistor coupling the respective pair of conductive layers together.

Assignees

• IBM

Inventors

• Biskeborn Robert G

Classifications

• G11B5/313

  Disposition of layers · CPC title

• G11B20/1816 Primary

  Testing · CPC title

• G11B2020/1826

  wherein a defect list or error map is generated · CPC title

• G11B5/00813

  magnetic tapes · CPC title

• G11B5/00817

  on longitudinal tracks only, e.g. for serpentine format recording · CPC title