TAPE STORAGE DEVICE, DATA WRITING METHOD, AND PROGRAM

• US 20120293886A1
• Filed: 05/17/2012
• Published: 11/22/2012
• Est. Priority Date: 05/19/2011
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Abe, Atsushi, Hagiwara, Katsuhiko
• Granted Patent: US 8,964,327 B2
• Time in Patent Office: Days
• US Class Current: 360/51
• CPC Class Codes: G06F 3/0613 in relation to throughput
• CPC Class Codes: G06F 3/0659 Command handling arrangements, e.g. command buffers, queues, command scheduling
• CPC Class Codes: G06F 3/0682 Tape device
• CPC Class Codes: G11B 2220/90 Tape-like record carriers
• CPC Class Codes: G11B 5/008 Recording on, or reproducing or erasing from, magnetic tapes, sheets, e.g. cards, or wires G11B15/00 G11B19/00 take precedence; bulk transferring of information magnetisation for re-recording G11B5/865; marking record carriers in digital fashion G06K

Abstract

A tape drive receives multiple write requests for data pieces and a synchronization request corresponding to the write requests from a device, performs a synchronization process, and returns a completion status of the synchronization request. The tape drive includes a write controller that stores data pieces transferred from the device in the buffer, according to a first write request, receives a first synchronization request and then a subsequent write request for at least one data piece, and returns the completion status when processing for the first synchronization request is completed and the subsequent write request is received with a command queuing function.

Claims

1. A tape drive that receives a plurality of write requests for data pieces and a synchronization request corresponding to the write requests from a device and returns a completion status of the synchronization request to the device, the tape drive comprising:

an interface that receives a command from the device;

a buffer that temporarily stores the data pieces sent from the device;

a tape medium on which the data pieces stored in the buffer are recorded; and

a write controller that records the data pieces on the tape medium from the buffer, wherein

the interface comprises a function for queuing commands issued in succession from the device so as to asynchronously process the commands, and

the write controller

(a) receives a first synchronization request and a subsequent write request for at least one data piece from the device, and

(b) returns the completion status when processing of the first synchronization request is completed and the subsequent write request is received with the command queuing.

2. The tape drive according to claim 1, wherein the write controller stores, as a first synchronization request position, a buffer position at which the last one of the data pieces stored in the buffer is located at the time of receiving a synchronization request for the data pieces stored in the buffer.

3. The tape drive according to claim 2, wherein the write controller performs control comprising:

(1) receiving data pieces corresponding to a plurality of first write requests from the device and storing the data pieces in the buffer;

(2) receiving a first synchronization request for the data pieces stored in the buffer from the device;

(3) storing the first synchronization request position by using a synchronization queue;

(4) receiving a plurality of second write requests as the subsequent write requests from the device while using the command queuing function;

(5) sending the device data transfer instructions responding to the second write requests;

(6) storing in the buffer data pieces transferred from the device in response to the data transfer instructions;

(7) checking if the last data piece stored at the buffer position corresponding to the first synchronization request is recorded on the tape medium;

(8) if the checking indicates that the data piece stored at the buffer position corresponding to the first synchronization request stored in the synchronization queue has been written to the tape medium, returning a completion status of the first synchronization request; and

(9) receiving a second synchronization request for the data pieces stored in the buffer from the device and executing the steps (3) to (8) for the second synchronization request and third write requests.

4. The tape drive according to claim 3, wherein the tape drive returns the completion status of the first synchronization request to the device after receiving the second write requests from the device.

5. The tape drive according to claim 4, wherein the tape drive returns the completion status of the first synchronization request to the device after sending the device the data transfer instructions responding to the second write requests.

6. The tape drive according to claim 5, wherein the tape drive returns the completion status of the first synchronization request to the device after receiving further second data pieces corresponding to the data transfer instructions from the device.

7. The tape drive according to claim 6, wherein the tape drive returns the completion status of the first synchronization request to the device after receiving the second synchronization request for the second data pieces from the device.

8. The tape drive according to claim 1, wherein the device is a host that issues the plurality of commands asynchronously to the tape drive.

9. A data writing method by which a tape drive receives a plurality of write requests for data pieces and a synchronization request corresponding to the write requests from a device and returns to the device a completion status of the synchronization request, wherein

the tape drive comprises an interface that receives a command from the device, a buffer that temporarily stores the data pieces sent from the device, a tape medium on which the data pieces stored in the buffer are recorded, and a write controller that records the data pieces on the tape medium from the buffer,

the tape drive further comprises a function for queuing commands issued in succession from the device so as to asynchronously process the commands, and

the method comprises:

(a) receiving a first synchronization request and then a subsequent write request for at least one data piece from the device; and

(b) returning a completion status when processing for the first synchronization request is completed and the subsequent write request is received with the command queuing.

10. The method according to claim 9, wherein the write controller stores, as a first synchronization request position, a buffer position at which the last one of the data pieces stored in the buffer is located at the time of receiving a synchronization request for the data pieces stored in the buffer.

11. The method according to claim 10, wherein the write controller performs control comprising:

(1) receiving data pieces corresponding to a plurality of first write requests from the device and storing the data pieces in the buffer;

(2) receiving a first synchronization request for the data pieces stored in the buffer from the device;

(3) storing the first synchronization request position by using a synchronization queue;

(4) receiving a plurality of second write requests as the subsequent write requests from the device while using the function of queuing the commands;

(5) sending the device data transfer instructions responding to the second write requests;

(6) storing in the buffer data pieces transferred from the device in response to the data transfer instructions;

(7) checking if the last data piece stored at the buffer position corresponding to the first synchronization request is recorded on the tape medium;

(8) if the checking indicates that the data piece stored at the buffer position corresponding to the first synchronization request stored in the synchronization queue has been written to the tape medium, returning a completion status of the first synchronization request; and

(9) receiving a second synchronization request for the data pieces stored in the buffer from the device and executing the steps (3) to (8) for the second synchronization request and third write requests.

12. The method according to claim 11, wherein the tape drive returns the completion status of the first synchronization request to the device after receiving the second write requests from the device.

13. The method according to claim 12, wherein the tape drive returns the completion status of the first synchronization request to the device after sending the device the data transfer instructions responding to the second write requests.

14. The method according to claim 13, wherein the tape drive returns the completion status of the first synchronization request to the device after receiving further second data pieces corresponding to the data transfer instructions from the device.

15. The method according to claim 14, wherein the tape drive returns the completion status of the first synchronization request to the device after receiving the second synchronization request for the second data pieces from the device.

16. The method according to claim 9, wherein the device is a host that issues the plurality of commands asynchronously to the tape drive.

17. A program for data writing for a tape drive including a computer that receives a plurality of write requests for data pieces and a synchronization request corresponding to the write requests from a device and returns to the device a completion status of the synchronization request, wherein the tape drive includes an interface that receives a command from the device, a buffer that temporarily stores the data pieces sent from the device, a tape medium on which the data pieces stored in the buffer are recorded, and a write controller that records the data pieces on the tape medium from the buffer,

the tape drive further comprises a function for queuing commands issued in succession from the device so as to asynchronously process the commands, and

the program causes the computer to execute the steps of:

(a) receiving a first synchronization request and then a subsequent write request for at least one data piece from the device, and

(b) returning a completion status when processing for the first synchronization request is completed and the subsequent write request is received with the command queuing.

18. The program according to claim 17, wherein the write controller stores, as a first synchronization request position, a buffer position at which the last one of the data pieces stored in the buffer is located at the time of receiving a synchronization request for the data pieces stored in the buffer.

19. The program according to claim 18, wherein the write controller performs control comprising:

(1) receiving data pieces corresponding to a plurality of first write requests from the device and storing the data pieces in the buffer;

(2) receiving a first synchronization request for the data pieces stored in the buffer from the device;

(3) storing the first synchronization request position by using a synchronization queue;

(4) receiving a plurality of second write requests as the subsequent write requests from the device while using the function of queuing the commands;

(5) sending the device data transfer instructions responding to the second write requests;

(6) storing in the buffer data pieces transferred from the device in response to the data transfer instructions;

(7) checking if the last data piece stored at the buffer position corresponding to the first synchronization request is recorded on the tape medium;

(8) if the checking indicates that the data piece stored at the buffer position corresponding to the first synchronization request stored in the synchronization queue has been written to the tape medium, returning a completion status of the first synchronization request; and

(9) receiving a second synchronization request for the data pieces stored in the buffer from the device and executing the steps (3) to (8) for the second synchronization request and third write requests.

20. The program according to claim 17, wherein the device is a host that issues the plurality of commands asynchronously to the tape drive.