Writing dummy indices on a tape medium partition

• US 9,536,561 B1
• Filed: 12/08/2015
• Issued: 01/03/2017
• Est. Priority Date: 12/08/2015
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Hasegawa, Tohru, Iwanaga, Masayuki, Oishi, Yutaka
• Primary Examiner(s): Wong, K.
• Application Number:
  US14/962,397
• Time in Patent Office: 392 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: G11B 20/1201 on tapes
• CPC Class Codes: G11B 27/107 of operating tapes
• CPC Class Codes: G11B 27/28 by using information signals recorded by the same method as the main recording G11B27/22 takes precedence
• CPC Class Codes: G11B 5/00817 on longitudinal tracks only, e.g. for serpentine format recording
• CPC Class Codes: G11B 5/09 Digital recording
• CPC Class Codes: G11B 5/86 Re-recording, i.e. transcribing information from one magnetisable record carrier on to one or more similar or dissimilar record carriers by varying the order of the information G11B27/029, G11B27/036

Abstract

A request for writing a first index information to a first partition of a serial storage medium of a serial system is received. The serial storage medium includes a first partition for writing the first index information including a first index position, a second partition for storing a data set, the data set including a second index information including a second index position, a memory for determining the second index position, and a module for writing the first index position. A beginning position of the first index is written on the first partition. A determination is made whether the beginning of the first index position is proximate to the second index position. In response to the beginning of the first index position being proximate to the second index position, an interrupted index position is registered. A dummy index is written to the first partition at the interrupted index position.

Claims

1. A method for storing data on a storage medium, the method comprising:

receiving a request for writing a first index information to a first partition of a tape medium of a tape drive, the tape medium including;

the first partition for writing the first index information starting at a first index position,

a second partition for storing a data set, the data set including a second index information starting at a second index position,

a non-volatile memory for storing the second index position, and

a module for writing the first index position;

writing a beginning portion of the first index information on the first partition at the first index position;

determining whether the beginning portion of the first index information is proximate to the second index position;

registering, in response to the determining that the beginning portion of the first index information is proximate to the second index position, an interrupted index position; and

writing a dummy index to the first partition starting at the interrupted index position to create a physical misalignment between the first index information on the first index partition and the second index information on the second partition.

2. The method of claim 1, wherein the dummy index overlaps the second index information.

3. The method of claim 1, wherein the determining whether the beginning portion of the first index information is proximate to the second index position includes:

determining, based on the first index information, the first index position, and the second index position, that the first index would at least partially overlap the second index if written continuously starting at the first index position.

4. The method of claim 1, wherein the beginning portion of the first index information starts at the first index position and ends at the interrupted index position, wherein the beginning portion does not overlap with the second index information, the method further comprising:

writing a second portion of the first index information to the first partition from a restarted index position to an end index position, wherein the restarted index position follows the dummy index, and wherein the second portion does not overlap with the second index information.

5. The method of claim 1, wherein the first index information includes the second index information and a second partition information, the second partition information directing the first index information to the second index information stored on the second partition.

6. The method of claim 1, wherein the determining whether the beginning portion of the first index information is proximate to the second index position includes:

determining that the index position of the first index information is within a threshold distance of the index position of the second index information.

7. The method of claim 6, wherein the threshold distance of the second index information is within 10 centimeters of magnetic tape.

8. The method of claim 1, wherein the first partition is an index partition and the second partition is a data partition in a linear tape file system.

9. The method of claim 1, wherein the first partition is encrypted using an encryption key.

10. The method of claim 1, the method further comprising:

determining a length of dummy data to write as the dummy index following the interrupted index position, the length of dummy data being at least an amount necessary to create the physical misalignment between the first index information on the first partition and the second index information on the second partition.

11. A system for storing data on a storage medium, the system comprising:

a memory;

a processing unit communicatively coupled to the memory;

a storage system communicatively coupled to the processing unit and the memory, the storage system including a tape storage medium, the tape storage medium comprising;

an index partition for writing a first index information starting at a first index position,

a data partition for storing a data set, the data set including a second index information starting at a second index position,

a non-volatile memory for storing the second index position, and

a module for recording the first index position; and

a tape controller, communicatively coupled to the storage system, configured to;

receive a request for writing the first index information to the index partition;

write a beginning portion of the first index information on the index partition at the first index position;

determine whether the beginning portion of the first index information is proximate to the second index position;

register, in response to the determining that the beginning portion of the first index information is proximate to the second index position, an interrupted index position; and

write a dummy index to the index partition starting at the interrupted index position to create a physical misalignment between the first index information on the index partition and the second index information on the data partition.

12. The system of claim 11, wherein the determining whether the beginning portion of the first index information is proximate to the second index position includes:

determining that the first index information starts at the first index position and ends at an end index position.

13. The system of claim 11, wherein the beginning portion of the first index information starts at the first index position and ends at the interrupted index position, wherein the beginning portion does not overlap with the second index information, and wherein the tape controller is further configured to:

write a second portion of the first index information to the index partition from a restarted index position to an end index position, wherein the restarted index position follows the dummy index, and wherein the second portion does not overlap with the second index information.

14. The system of claim 11, wherein the tape controller is further configured to:

determine a length of dummy data to write as the dummy index following the interrupted index position, the length of dummy data being at least an amount necessary to create the physical misalignment between the first index information on the index partition and the second index information on the data partition.

15. A computer program product for storing data on a storage medium, comprising a computer readable storage medium having a computer readable program stored therein, wherein the computer readable program, when executed on a computing device, causes the computing device to:

receive a request for writing a first index information to a first partition of a serial storage medium of a serial storage system, the serial storage medium including;

the first partition for writing the first index information starting at a first index position,

a second partition for storing a data set, the data set including a second index information starting at a second index position,

a non-volatile memory for storing the second index position, and

a module for recording the first index position;

write a beginning portion of the first index information on the first partition at the first index position;

determine whether the beginning portion of the first index information is proximate to the second index position;

register, in response to the determining that the beginning portion of the first index information is proximate to the second index position, an interrupted index position; and

write a dummy index to the first partition starting at the interrupted index position to create a physical misalignment between the first index information and the second index information.

16. The computer program product of claim 15, wherein the determining whether the beginning portion of the first index information is proximate to the second index position includes:

determining that the first index information starts at the first index position and ends at an end position.

17. The computer program product of claim 15, wherein the beginning portion of the first index information starts at the first index position and ends at the interrupted index position, wherein the beginning portion does not overlap with the second index information, and wherein the computing device is further configured to:

write a second portion of the first index information to the first partition from a restarted index position to an end index position, wherein the restarted index position follows the dummy index, and wherein the second portion does not overlap with the second index information.

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

determining a length of dummy data to write as the dummy index following the interrupted index position, the length of dummy data being at least an amount necessary to create the physical misalignment between the first index information on the first partition and the second index information on the second partition.