METHOD AND APPARATUS TO SET A WRAP ANGLE OF A READ/WRITE HEAD

• US 20110013313A1
• Filed: 07/17/2009
• Published: 01/20/2011
• Est. Priority Date: 07/17/2009
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: OGURA, EIJI, BUI, NHAN XUAN, HANCOCK, REED ALAN, TSURUTA, KAZUHIRO, HUTCHINS, ROBERT ALLEN
• Granted Patent: US 7,990,649 B2
• Time in Patent Office: Days
• US Class Current: 360/77.12
• CPC Class Codes: G11B 15/602 for track selection, acquisition or following
• CPC Class Codes: G11B 15/62 Maintaining desired spacing between record carrier and head
• CPC Class Codes: G11B 5/0083 for parallel information processing, e.g. PCM recording
• CPC Class Codes: G11B 5/584 for track following on tapes
• CPC Class Codes: G11B 5/78 Tape carriers

Abstract

A method is presented for setting a wrap angle of a read/write head having a servo element and multiple read elements, where the servo element and the read elements can detect a servo signal. The method includes moving a sequential information storage medium having a longitudinal axis and a servo band encoded therein adjacent to the read/write head. The longitudinal axis and a flat upper surface of the read write head define the wrap angle. The method further includes detecting the servo signal using one of the read elements. If the read element is unable to detect the servo signal, then the remaining read elements are sensed to detect the servo signal.

Claims

1. A method for setting a wrap angle of a read/write head, comprising:

supplying a read head/write head comprising a roller, a sloping upper surface, a servo element, and a plurality of servo band detection enabled read elements (“

Enabled Read Elements”

), wherein the servo element and each of the plurality of Enabled Read Elements can detect a servo band,

moving a sequential information storage medium across said roller and said sloping upper surface at an initial wrap angle, wherein said sequential information storage medium comprises a servo band encoded therein and a longitudinal axis, wherein the longitudinal axis and the sloping upper surface define said initial wrap angle;

incrementally adjusting said initial wrap angle by incrementally moving said roller until said servo band is not detected by the servo band or by any of the plurality of Enabled Read Elements;

determining a nominal wrap angle; and

setting an operating wrap angle.

2. The method of claim 1, further comprising:

determining if said servo band is detected by an Enabled Read Element;

operative if said servo band is detected by an Enabled Read Element, laterally adjusting the position of said read head with respect to said sequential information storage medium based upon the location of said Enabled Read Element detecting said servo band.

3. The method of claim 1, further comprising:

establishing an iteration number (N), wherein (N) is greater than or equal to 2;

wherein said incrementally adjusting step comprises adjusting an (i)th wrap angle to form an (i+1)th wrap angle, wherein (i) is greater than or equal to 1 and less than or equal to (N).

4. The method of claim 3, wherein said incrementally adjusting step further comprises:

operative if an initial wrap angle was about 0 degrees, increasing said (i)th wrap angle to form said (i+1)th wrap angle;

operative if said initial wrap angle was about 4 degrees, decreasing said (i)th wrap angle to form said (i+1)th wrap angle.

5. The method of claim 4, wherein:

said increasing step comprises moving said roller in a first direction;

said decreasing step comprises moving said roller in a second direction, wherein said first direction is opposite said second direction.

6. The method of claim 3, further comprising:

incrementally adjusting, for each value of (i), an (i)th wrap angle until said servo band is not detected by the servo band or by any of the plurality of Enabled Read Elements;

saving, for each value of (i), an (i)th nominal wrap angle; and

calculating an average nominal wrap angle.

7. The method of claim 6, further comprising:

establishing a wrap angle offset;

setting an operating wrap angle equal to said average nominal wrap angle plus said wrap angle offset.

8. An article of manufacture comprising a computer readable medium comprising computer readable program code disposed therein for setting a wrap angle of a read/write head comprising a roller, a sloping upper surface, a servo element, and a plurality of servo band detection enabled read elements (“

Enabled Read Elements”

), wherein the servo element and each of the plurality of Enabled Read Elements can detect a servo band, the computer readable program code comprising a series of computer readable program steps to effect;

moving a sequential information storage medium across said roller and said sloping upper surface at an initial wrap angle, wherein said sequential information storage medium comprises a servo band encoded therein and a longitudinal axis, wherein the longitudinal axis and the sloping upper surface define said initial wrap angle;

incrementally adjusting said initial wrap angle by incrementally moving said roller until said servo band is not detected by the servo band or by any of the plurality of Enabled Read Elements;

determining a nominal wrap angle; and

setting an operating wrap angle.

9. The article of manufacture of claim 8, said computer readable program code further comprising a series of computer readable program steps to effect:

determining if said servo band is detected by an Enabled Read Element;

operative if said servo band is detected by an Enabled Read Element, laterally adjusting the position of said sequential information storage medium with respect to said read head based upon the location of said Enabled Read Element detecting said servo band.

10. The article of manufacture of claim 8, said computer readable program code further comprising a series of computer readable program steps to effect:

establishing an iteration number (N), wherein (N) is greater than or equal to 2;

wherein said computer readable program code to incrementally adjust an initial wrap angle further comprises a series of computer readable program steps to effect adjust an (i)th wrap angle to form an (i+1)th wrap angle, wherein (i) is greater than or equal to 1 and less than or equal to (N).

11. The article of manufacture of claim 10, wherein said computer readable program code to incrementally adjust an initial wrap angle further comprises a series of computer readable program steps to effect:

operative if an initial wrap angle was about 0 degrees, increasing said (i)th wrap angle to form said (i+1)th wrap angle;

operative if said initial wrap angle was about 4 degrees, decreasing said (i)th wrap angle to form said (i+1)th wrap angle.

12. The article of manufacture of claim 11, wherein:

said computer readable program code to increase said (i)th wrap angle to form said (i+1)th wrap angle further comprising a series of computer readable program steps to effect moving said roller downwardly;

said computer readable program code to decrease said (i)th wrap angle to form said (i+1)th wrap angle further comprising a series of computer readable program steps to effect moving said roller upwardly.

13. The article of manufacture of claim 10, said computer readable program code further comprising a series of computer readable program steps to effect:

incrementally adjusting, for each value of (i), an (i)th wrap angle until said servo band is not detected by the servo band or by any of the plurality of Enabled Read Elements;

saving, for each value of (i), an (i)th nominal wrap angle; and

calculating an average nominal wrap angle.

14. The article of manufacture of claim 13, said computer readable program code further comprising a series of computer readable program steps to effect:

establishing a wrap angle offset;

setting an operating wrap angle equal to said average nominal wrap angle plus said wrap angle offset.

15. A computer program product encoded in a computer readable medium and useable with a programmable computer processor for setting a wrap angle of a read/write head comprising a roller, a sloping upper surface, a servo element, and a plurality of servo band detection enabled read elements (“

Enabled Read Elements”

), wherein the servo element and each of the plurality of Enabled Read Elements can detect a servo band,, the computer program product comprising;

computer readable program code which causes said programmable processor to move a sequential information storage medium across said roller and said sloping upper surface at an initial wrap angle, wherein said sequential information storage medium comprises a servo band encoded therein and a longitudinal axis, wherein the longitudinal axis and the sloping upper surface define said initial wrap angle;

computer readable program code which causes said programmable processor to incrementally adjust said initial wrap angle by incrementally moving said roller until said servo band is not detected by the servo band or by any of the plurality of Enabled Read Elements;

computer readable program code which causes said programmable processor to determine a nominal wrap angle; and

computer readable program code which causes said programmable processor to set an operating wrap angle.

16. The computer program product of claim 15, further comprising:

computer readable program code which, if said servo band is detected by an Enabled Read Element, causes said programmable processor to laterally adjust the position of said sequential information storage medium with respect to said read head based upon the location of said Enabled Read Element detecting said servo band.

17. The computer program product of claim 16, further comprising:

computer readable program code which causes said programmable processor to establish an iteration number (N), wherein (N) is greater than or equal to 2;

wherein said computer readable program code to incrementally adjust an initial wrap angle further comprises computer readable program code which causes said programmable processor to adjust an (i)th wrap angle to form an (i+1)th wrap angle, wherein (i) is greater than or equal to 1 and less than or equal to (N).

18. The computer program product of claim 16, further comprising:

computer readable program code which, if an initial wrap angle was about 0 degrees, causes said programmable processor to increase said (i)th wrap angle to form said (i+1)th wrap angle;

computer readable program code which, if an initial wrap angle was about 4 degrees, causes said programmable processor to decrease said (i)th wrap angle to form said (i+1)th wrap angle

19. The computer program product of claim 17, wherein:

computer readable program code which causes said programmable processor to incrementally adjust, for each value of (i), an (i)th wrap angle until said servo band is not detected by the servo band or by any of the plurality of Enabled Read Elements;

computer readable program code which causes said programmable processor to saving, for each value of (i), an (i)th nominal wrap angle; and

computer readable program code which causes said programmable processor to calculate an average nominal wrap angle.

20. The computer program product of claim 19, further comprising computer readable program code which causes said programmable processor to set an operating wrap angle equal to said average nominal wrap angle plus a wrap angle offset.