Servo pattern of a tape storage medium

Patent metadata

Field	Value
Publication number	US-9251827-B2
Application number	US-201314646084-A
Country	US
Kind code	B2
Filing date	Nov 27, 2013
Priority date	Nov 30, 2012
Publication date	Feb 2, 2016
Grant date	Feb 2, 2016

Abstract

A tape storage medium comprises at least one servo band along a longitudinal extension of the tape storage medium for comprising positional information. The servo band comprises a first servo subband and a second servo subband extending along the longitudinal extension of the tape storage medium. The first servo subband comprises a frame servo pattern containing a first set of servo frames, wherein each servo frame of the set comprises a first burst and a second burst. Each burst comprises at least two servo stripes inclined at an angle with respect to a direction orthogonal to the longitudinal extension of the tape medium. The second servo subband contains a set of servo tracks extending along the longitudinal extension of the tape storage medium and arranged next to each other, wherein each servo track of the set contains a servo pattern of magnetic transitions.

First claim

The invention claimed is:

1. A tape storage medium comprising:
a tape storage medium comprising at least one servo band along a longitudinal extension of the tape storage medium, wherein the at least one servo band comprises positional information, and wherein the servo band further comprises:
a first servo subband extending along the longitudinal extension of the tape storage medium, the first servo subband comprising:
a first frame servo pattern containing a first set of servo frames, wherein each servo frame of the set comprises:
a first burst comprising at least one servo stripe inclined at a first angle with respect to a direction orthogonal to the longitudinal extension of the tape storage medium; and
a second burst comprising at least one servo stripe inclined at a second angle with respect to the direction orthogonal to the longitudinal extension of the tape storage medium, the second angle being different from the first angle;

a second servo subband extending along the longitudinal extension of the tape storage medium next to the first servo subband, the second servo subband comprising:
a set of servo tracks extending along the longitudinal extension of the tape storage medium and arranged next to each other;
wherein each servo track of the set contains a servo pattern representing a waveform when being read; and
wherein the waveforms of adjacent servo tracks are orthogonal to each other.

2. The tape storage medium according to claim 1 ,
wherein the servo pattern of each servo track of the set contains magnetic transitions at a defined frequency; and
wherein the frequencies of magnetic transitions of servo patterns of adjacent servo tracks are different from each other.

3. The tape storage medium according to claim 2 ,
wherein a lowest frequency of magnetic transitions in any of the servo tracks of the set is more than a repetition frequency of the servo frames in the first subband.

4. The tape storage medium of claim 2 ,
wherein the lowest frequency is more than twice the repetition frequency of the servo frames in the first subband.

5. The tape storage medium of claim 2 ,
wherein the lowest frequency is more than ten times the repetition frequency of the servo frames in the first subband.

6. Tape storage medium according to claim 1 ,
wherein the servo pattern of each servo track of the set contains a pseudo noise sequence of symbols; and
wherein the pseudo noise sequences of servo patterns of adjacent servo tracks are different from each other.

7. The tape storage medium of claim 6 ,
wherein a length of the pseudo noise sequence in the servo tracks is less than half the length of the servo frame in the first servo subband.

8. The tape storage medium according to claim 6 ,
wherein a length of the pseudo noise sequence in the servo tracks is less than a length of the servo frame in the first servo subband.

9. Tape storage medium according to claim 1 ,
wherein the servo band comprises a third servo subband extending along the longitudinal extension of the tape storage medium comprising a second frame servo pattern containing a second set of servo frames.

10. The tape storage medium of claim 9 ,
wherein a length of the pseudo noise sequence in the servo tracks is less than a tenth of the length of the servo frame in the first servo subband.

11. The tape storage medium according to claim 9 ,
wherein the second frame servo pattern of the third servo subband is identical to the first frame servo pattern of the first servo subband; and
wherein the third servo subband is arranged next to the second servo subband.

12. The tape drive according to claim 1 further comprising:
a tape head, comprising:
a first servo reader assigned for reading from the servo band; and
a second servo reader assigned for reading from the servo band.

13. Tape drive according to claim 12 ,
wherein the first servo reader and the second servo reader are arranged adjacent to each other orthogonal to the longitudinal extension of the tape storage medium when arranged in the tape drive; and
wherein the first servo reader and the second servo reader are mechanically coupled at a fix distance from each other.

14. Tape drive according to claim 13 ,
wherein a width of the second servo reader orthogonal to the longitudinal extension of the tape storage medium when arranged in the tape drive is at least a width of a servo track in the second servo subband orthogonal to the longitudinal extension of the tape storage medium; and
wherein the width of the second servo reader is equal to the width of the first servo reader.

15. Tape drive according to claim 14 ,
wherein the tape head contains a third servo reader assigned for reading from the servo band and arranged adjacent to the second servo reader orthogonal to the longitudinal extension of the tape storage medium when arranged in the tape drive.

16. A method for operating a tape drive for a tape storage medium, comprising:
reading, by one or more processors, a first servo subband by a first servo reader;
determining, by one or more processors, a first lateral position value of a tape head comprising the first servo reader relative to a tape storage medium from a readback signal of the first servo reader and adjusting a lateral position of the tape head dependent on the first lateral position value;
reading, by one or more processors, a second servo subband by a second servo reader; and
determining, by one or more processors, a second lateral position value of the tape head comprising the second servo reader relative to the tape storage medium from a readback signal of the second servo reader and adjusting the lateral position of the tape head dependent on the second lateral position value.

17. Method according to claim 16 ,
wherein determining the second lateral position value comprises:
identifying, by one or more processors, one or more waveforms in the readback signal of the servo reader reading the second servo subband.

18. The method according to claim 16 , further comprising:
reading, by one or more processors, a first servo subband and a second servo subband simultaneously;
determining, by one or more processors, the first lateral position value at a repetition frequency of a set of servo frames in the first servo subband; and
determining, by one or more processors, the second lateral position value at a second frequency exceeding the repetition frequency, and adjusting the lateral position of the tape head dependent on the first and second lateral position values.

19. A computer program product, the computer program product comprising:
a computer readable storage medium and program instructions stored on the computer readable storage medium, the program instructions comprising:
program instructions to read a first servo subband by a first servo reader;
program instructions to determine a first lateral position value of a tape head comprising the first servo reader relative to a tape storage medium from a readback signal of the first servo reader and adjusting a lateral position of the tape head dependent on the first lateral position value;
program instructions to read a second servo subband by a second servo reader; and
program instructions to determine a second lateral position value of the tape head comprising the second servo reader relative to the tape storage medium from a readback signal of the second servo reader and adjusting the lateral position of the tape head dependent on the second lateral position value.

Assignees

• IBM

Inventors

• Cherubini Giovanni
• Engelen Johan B C
• Furrer Simeon
• Jelitto Jens
• Lantz Mark A

Classifications

• G11B5/584 Primary

  for track following on tapes · CPC title