Tape width measurements

• US 8,896,958 B2
• Filed: 01/19/2012
• Issued: 11/25/2014
• Est. Priority Date: 01/19/2012
• Status: Active Grant

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Fasen, Donald J, McAllister, Jeffrey S
• Primary Examiner(s): Negron, Daniell L
• Application Number:
  US13/353,442
• Publication Number:
  US 20130188271A1
• Time in Patent Office: 1,041 Days
• Field of Search: None
• US Class Current: 360/72.1
• CPC Class Codes: G11B 15/06 by sensing auxiliary features on record carriers or containers, e.g. to stop machine near the end of a tape
• CPC Class Codes: G11B 15/093 by sensing driving condition of record carrier, e.g. travel, tape tension
• CPC Class Codes: G11B 15/43 Control or regulation of mechanical tension of record carrier, e.g. tape tension

Abstract

A tape drive is disclosed. The tape drive determines a current tape width and writes data to the tape as well as the current tape width. The tape width written to the tape is associated with the data. When reading data from a tape the tape drive reads the stored tape width and adjusts the current tape width to match the stored tape width before reading the data associated with the stored tape width.

Claims

1. A tape drive, comprising:

a first and a second servo element to read a number of azimuthally sloped transitions on a first and a second servo band on a tape traveling in a first direction;

a servo processor to calculate a current tape width by determining a distance between the first and second servo bands;

a tape tensioning system to adjust the current tape width to a predetermined tape width before writing information to the tape;

a controller to write information to the tape;

the controller writing data to the tape and writing the current tape width onto the tape, wherein the current tape width is associated to the data.

2. The tape drive of claim 1, wherein the tape is in the linear tape-open (LTO) format.

3. The tape drive of claim 1, wherein the current tape width is stored in a header of the data or other recoverable sections of the data.

4. The tape drive of claim 1, further comprising:

a tape tensioning system to adjust a current tape tension to a nominal tension wherein data is written to the tape using the nominal tension.

5. The tape drive of claim 1, further comprising:

a tape tensioning system to adjust the current tape width to a nominal tape width by change a tension in the tape before writing the data to the tape.

6. The tape drive of claim 1, further comprising a third and a fourth servo element to read the first and the second servo band on the tape travelling in a second direction.

7. The tape drive of claim 1, further comprising:

a tape width system to adjust a current tape width to a nominal width wherein data is written to the tape using the nominal width.

8. The tape drive of claim 1, wherein the predetermined tape width is based on a maximum tape tension, a minimum tape tension, or combinations thereof.

9. The tape drive of claim 1, wherein the tape tensioning system adjusts the current tape width to a tape width determined for tapes of a same type as the tape.

10. A method of writing data to a tape, comprising:

reading a number of azimuthally sloped transitions on a first and second servo band on a tape traveling in a first direction;

calculating a current tape width by determining a distance between the first and second servo bands;

adjusting the current tape width towards a predetermined tape width by changing a tension in the tape before writing the data to the tape;

writing the data onto the tape;

writing the measured tape width onto the tape and associating the measured tape width to the data.

11. The method of claim 10, wherein the current tape width is measured with a nominal tension in the tape.

12. A tape drive, comprising:

a first and a second servo element to read a first and a second servo band on a tape traveling in a first direction;

a servo processor to calculate a current tape width by determining a distance between the first and second servo band;

a controller to read data from the tape using a nominal tape tension;

a tape tensioning system to adjust the current tape width to a predetermined tape width before writing information to the tape;

the controller writing data to the tape and writing the current tape width onto the tape, wherein the current tape width is associated to the data.

13. The tape drive of claim 12, wherein the tape is in the linear tape-open (LTO) format.

14. The tape drive of claim 12, wherein the current tape width is stored in a header or other recoverable sections of the data.

15. The tape drive of claim 12, further comprising a third and a fourth servo element to read the first and the second servo band on the tape travelling in a second direction.

16. The tape drive of claim 12, wherein the tape tensioning system adjusts the current tape width by changing a tension in the tape to a threshold amount.

17. The tape drive of claim 12, further comprising a corruption detector to detect if either of the first and the second servo band are corrupted.

18. A method of reading data from a tape, comprising:

determining when there is a stored tape width associated with the data when there is a stored tape width associated with data;

reading from the tape, a stored tape width associated with data stored onto the tape;

adjusting the tension in the tape to change the current tape width to more closely match the stored tape width when the current tape width is a threshold amount greater than the stored tape width; and

reading the associated data from the tape;

when there is not a stored tape width associated with the data;

reading data from the tape using a nominal tape tension;

calculating an initial delta error rate between an error rate in at least one center data track and an error rate in at least one outer data track;

when the initial delta error rate is above a threshold;

changing the width of the tape to a new tape width by adjusting the tension in the tape;

reading data from the tape using the new tape width and calculating a new delta error rate between an error rate in at least one center data track and an error rate in at least one outer data track;

optimizing the tape width by reducing the new delta error rate to a minimum;

reading the data from the tape using the optimized tape width;

when the initial delta error rate is not above a threshold;

reading the data from the tape using the nominal tape tension.

19. The method of claim 18, further comprising manipulating servo code stored on servo bands of the tape.