Magnetic recording control apparatus

• US 5,327,535 A
• Filed: 08/25/1992
• Issued: 07/05/1994
• Est. Priority Date: 08/29/1991
• Status: Expired due to Term

• Current Assignee: Hitachi Computer Engineering Company Limited (Hitachi, Ltd.), Hitachi, Ltd.
• Original Assignee: Hitachi Computer Engineering Company Limited (Hitachi, Ltd.), Hitachi, Ltd.
• Inventors: Nakamura, Takahiko, Ogata, Mikito, Nishimura, Toshifumi
• Primary Examiner(s): Shaw, Dale M.
• Assistant Examiner(s): Meky, Moustafa M.
• Application Number:
  US07/935,843
• Time in Patent Office: 679 Days
• Field of Search: 395/275, 395/250, 395/425
• US Class Current: 711/113
• CPC Class Codes: G06F 3/0601 Interfaces specially adapted for storage systems
• CPC Class Codes: G06F 3/0656 Data buffering arrangements
• CPC Class Codes: G06F 3/0682 Tape device

Abstract

A magnetic recording control apparatus includes conventional magnetic recording media, a large capacity type magnetic recording medium having a memory capacity corresponding to the sum of the capacities of a plurality of conventional magnetic recording media, recording unit for recording data of a plurality of conventional magnetic recording media to the large capacity type magnetic recording medium using a virtual volume corresponding to the recording capacity of one conventional magnetic recording medium and control data relating to the virtual volume as one recording unit, and/or division unit for dividing a data buffer for temporarily storing the data of the large capacity type magnetic recording medium into logical devices corresponding to the conventional magnetic recording media.

Claims

1. A magnetic recording control apparatus for controlling a magnetic recording device dealing with a large capacity type magnetic recording medium having a capacity of a plurality of normal capacity type magnetic recording media, said apparatus being connected to a host computer, comprising:

a data buffer for storing data;

a processor;

a memory for storing control data; and

a transmitter for transmitting data stored in said buffer to the magnetic recording device as a virtual volume, and transmitting control data to identify the virtual volume wherein said control data is recorded at either one of a head or a tail of the virtual volume on the magnetic recording medium,

wherein a plurality of virtual volumes are stored in the magnetic recording medium and said processor stores information for identifying the virtual volume as said control data in said memory.

2. A magnetic recording control apparatus according to claim 1, wherein said large capacity type recording medium is a magnetic tape.

3. A magnetic recording control apparatus according to claim 2, wherein said magnetic tape is a cassette type magnetic tape which does not require rewinding of all tape when said magnetic tape is demounted from said magnetic recording control apparatus.

4. A magnetic recording control apparatus according to claim 3, wherein each of said control data contains location information of corresponding virtual volume and other virtual volumes stored in said magnetic tape.

5. A magnetic recording control apparatus according to claim 4, wherein said processor outputs an instruction to move a recording position of said magnetic tape to a region storing said control data and writes said control data when an access to said virtual volume is completed due to an instruction from said host computer and a tape demount instruction is generated from said host computer.

6. A magnetic recording control apparatus according to claim 5, wherein said processor searches said region storing said control data, and outputs an instruction for reading said control data, when receiving a signal from said host computer representing that said cassette type tape is mounted to said control apparatus.

7. A magnetic recording control apparatus for controlling a magnetic recording device dealing with a large capacity type magnetic recording medium having a capacity of a plurality of normal capacity type magnetic recording media, said apparatus being connected to a host computer, comprising:

a data buffer for storing data, said data buffer being divided into a plurality of logical devices;

a processor;

a memory for storing control data; and

a transmitter for transmitting data stored in said each of logical devices to the magnetic recording device as a virtual volume, and transmitting control data to identify the virtual volume such that the control data is recorded at either one of a head or a tail of said each virtual volume on the magnetic recording medium,

wherein capacity of each logical device is equal to a capacity of a virtual volume, a plurality of virtual volumes are stored in the magnetic recording medium and said processor stores information for identifying the virtual volume as said control data in said memory.

8. A magnetic recording control apparatus according to claim 7, wherein the number of said logical devices on said data buffer is equal to the number of said virtual volumes.

9. A magnetic recording control apparatus according to claim 7, wherein data is read from said virtual volume into said logical device on said data buffer when receiving a mount request of said magnetic recording medium from said host computer, a write/read processing into and from said virtual volume is executed on said logical device, and data on said logical device is written into a corresponding virtual volume on said magnetic tape when receiving a demount request of said magnetic recording medium from said host computer.

10. A magnetic recording control apparatus according to claim 7, wherein coordination between a plurality of said logical devices and a plurality of said virtual volumes is automatically allotted by said magnetic recording control apparatus.

11. A magnetic recording control apparatus according to claim 7, wherein said logical devices on said data buffer are used for copying data on said logical devices to the logical devices.

12. A magnetic recording control apparatus according to claim 7, wherein said logical devices on said data buffer sequentially merge data on said logical devices to an end of data on other logical devices and write whole data into one logical device.

13. A magnetic recording control apparatus according to claim 7, wherein said large capacity type recording medium is a magnetic tape.

14. A magnetic recording control apparatus according to claim 7, wherein said transmitter detects a failure of writing data into said corresponding virtual volume on the magnetic recording medium when demounting of said magnetic recording medium due to an instruction from said host computer, and is responsive to detection of the failure to transmit said data into an empty virtual volume on said magnetic recording medium and nullify the failed virtual volume.

15. A magnetic recording control apparatus according to claim 7, wherein said transmitter does not transmit the data in said logical device to the virtual volume on the magnetic medium if the data in said logical device has not been updated.

16. In a magnetic recording control apparatus for controlling a magnetic recording device dealing with a large capacity type magnetic recording medium having a capacity of a plurality of normal capacity type magnetic recording media, connected to a host device, and said magnetic recording control apparatus comprising a data buffer, and a transmitter, a method for using a large capacity type magnetic recording medium as a plurality of normal capacity type magnetic recording media in parallel comprising the steps of:

defining a plurality of virtual volumes on the large capacity type magnetic recording medium;

storing control data in memory to identify the virtual volume in the magnetic recording device;

defining a plurality of logical devices, each logical device corresponding to a virtual volume;

assigning the logical devices to the data buffer;

receiving data from the host device and storing the data temporarily in the logical devices which the host device designates; and

transmitting data in the logical device with said control data to the corresponding virtual volume in the large capacity type magnetic recording medium.