LOCATING DATA STORED ON A MAGNETIC MEDIUM

• US 20150098149A1
• Filed: 10/09/2013
• Published: 04/09/2015
• Est. Priority Date: 10/09/2013
• Status: Active Grant

• Current Assignee: GlobalFoundries, Inc.
• Original Assignee: International Business Machines Corporation
• Inventors: Bates, Allen K., Bui, Nhan X., Winarski, Daniel J.
• Granted Patent: US 9,183,851 B2
• Time in Patent Office: Days
• US Class Current: 360/72.1
• CPC Class Codes: G11B 2220/63 wherein solid state memory is used as a supplementary storage medium to store auxiliary data for detecting or correcting errors on a main storage medium
• CPC Class Codes: G11B 2220/93 Longitudinal format, wherein tracks are in the direction of the tape, read with a static head, e.g. DCC
• CPC Class Codes: G11B 27/11 by using information not detectable on the record carrier
• CPC Class Codes: G11B 27/3027 used signal is digitally coded
• CPC Class Codes: G11B 5/00 Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor G11B11/00 and G11B13/00 take precedence
• CPC Class Codes: G11B 5/584 for track following on tapes

Abstract

A set of lateral positions, of the magnetic medium with respect to the tape reel and a set of longitudinal positions of the magnetic medium with respect to the beginning of the magnetic medium as the magnetic medium comes off the first tape reel, are identified. A record is stored, on a non-volatile storage medium, of the set of lateral positions of the magnetic medium and the set of longitudinal positions of the magnetic medium. The record, of the set of lateral positions of the magnetic medium and the set of longitudinal positions of the magnetic medium as the magnetic medium comes off a second tape reel, is read. A tape head is moved laterally, to the lateral positions in response to the reading of the record of the set of lateral positions of the magnetic medium and the set of longitudinal positions of the magnetic medium.

Claims

1. A method of locating data stored on a magnetic tape/the method comprising:

performing a first unwinding of the magnetic tape from a first tape reel;

reading lateral positions of the magnetic tape with respect to the first tape reel and corresponding longitudinal positions of the magnetic tape with respect to a beginning of the magnetic tape during the first unwinding;

determining that one or more of the read lateral positions read during the first unwinding exceeds a buffer zone between data tracks of the magnetic tape;

storing a record of the one or more lateral positions of the magnetic tape and a corresponding set of the corresponding longitudinal positions of the magnetic tape;

winding the magnetic tape on to a second tape reel;

performing a second unwinding of the magnetic tape from the second tape reel;

reading the record of the one or more lateral positions of the magnetic tape and the corresponding set of the corresponding longitudinal positions of the magnetic tape during the second unwinding; and

moving a tape head laterally during the second unwinding in response to the reading of the record of the one or more lateral positions of the magnetic tape and the corresponding set of the corresponding longitudinal positions of the magnetic tape.

2. The method of claim 1, further comprising:

reducing a velocity of the second unwinding of the magnetic tape in response to the reading of the record of the one or more lateral positions of the magnetic tape and the corresponding set of the corresponding longitudinal positions of the magnetic tape.

3. The method of claim 1, wherein the performing of the winding the magnetic tape on to the second tape reel is performed concurrently with the first unwinding of the magnetic tape from the first tape reel.

4. The method of claim 1, wherein the record is stored on a cartridge memory.

5. The method of claim 1, wherein the record is stored on a succeeding header of data on the magnetic tape.

6. The method of claim 1, wherein the record is stored on a trailer of data on the magnetic tape.

18. The method of claim 1, wherein the first and second tape reels are the same tape reel and the winding of the magnetic tape on to the second tape reel is a winding of the magnetic tape back on to the first tape reel performed subsequent to the first unwinding of the magnetic tape from the first tape reel.

7. A system of locating data stored on a magnetic tape, the system comprising:

a recording tool configured to;

read lateral positions of the magnetic tape with respect to a first tape reel and corresponding longitudinal positions of the magnetic tape with respect to a beginning of the magnetic medium tape as the magnetic medium comes off the first tape during a first unwinding;

determine that one or more of the read lateral positions read during the first unwinding exceeds a buffer zone between data tracks of the magnetic tape;

a non-volatile storage medium configured to;

store a record of the one or more lateral positions of the magnetic tape and a corresponding set of the corresponding longitudinal positions of the magnetic tape; and

a controller configured to;

perform the first unwinding of the magnetic tape from the first tape reel;

wind the magnetic tape on to a second tape reel;

perform a second unwinding of the magnetic tape from the second tape reel;

read the record of the one or more lateral positions of the magnetic tape and the corresponding set of the corresponding longitudinal positions of the magnetic tape during the second unwinding; and

move a tape head laterally during the second unwinding in response to the reading of the record of the one or more lateral positions of the magnetic tape and the corresponding set of the corresponding longitudinal positions of the magnetic tape.

8. The system of claim 7, wherein the controller is further configured to:

reduce a velocity of the second unwinding of the magnetic tape in response to the reading of the record of the one or more lateral positions of the magnetic tape and the corresponding set of the corresponding longitudinal positions of the magnetic tape.

9. The system of claim 7, wherein the controller is configured to perform the winding the magnetic tape on to the second tape reel concurrently with the first unwinding of the magnetic tape from the first tape reel.

10. The system of claim 7, wherein the non-volatile storage medium is a cartridge memory.

11. The system of claim 7, wherein the non-volatile storage medium is a header of data on the magnetic tape.

12. The system of claim 7, wherein the non-volatile storage medium is a trailer of data on the magnetic tape.

19. The system of claim 7, wherein the first and second tape reels are the same tape reel and the controller is configured to wind the magnetic tape on to the second tape reel and back on to the first tape reel, subsequent to the first unwinding of the magnetic tape from the first tape reel.

13. A device for storing a record of lateral shifts of a magnetic tape, the device comprising:

a tape reel;

a magnetic tape configured to have its lateral positions with respect to the tape reel and corresponding longitudinal positions with respect to a beginning of the magnetic tape, read during a first unwinding;

a non-volatile storage medium configured to store a record of one or more of the lateral positions of the magnetic tape and a corresponding set of the corresponding longitudinal positions of the magnetic tape read during the first unwinding and further configured to have the record of the one or more lateral positions of the magnetic tape and the corresponding set of the corresponding longitudinal positions of the magnetic tape, read during a second unwinding of the magnetic tape; and

a tape reel cartridge configured to store the tape reel and the magnetic tape.

14. The device of claim 13, wherein the non-volatile storage medium is a cartridge memory stored on the tape reel cartridge.

15. The device of claim 13, wherein the non-volatile storage medium is a header of data on the magnetic tape.

16. The device of claim 13, wherein the non-volatile storage medium is a trailer of data on the magnetic tape.

17. The device of claim 13, wherein the magnetic tape is wound on the tape reel.