RECORDING APPARATUS AND CONTROL CIRCUIT

• US 20090103203A1
• Filed: 09/10/2008
• Published: 04/23/2009
• Est. Priority Date: 10/22/2007
• Status: Abandoned Application

• Current Assignee: Toshiba Storage Device Incorporated (Toshiba Corporation)
• Original Assignee: Fujitsu Limited
• Inventors: Yoshida, Osamu
• Application Number:
  US12/208,041
• Publication Number:
  US 20090103203A1
• Time in Patent Office: Days
• US Class Current: 360/75
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 12/0804 with main memory updating G06F12/0806 takes precedence
• CPC Class Codes: G06F 12/0871 Allocation or management of cache space
• CPC Class Codes: G06F 2212/1036 Life time enhancement
• CPC Class Codes: G06F 2212/217 Hybrid disk, e.g. using both magnetic and solid state storage devices
• CPC Class Codes: G06F 2212/222 Non-volatile memory
• CPC Class Codes: G06F 2212/7211 Wear leveling
• CPC Class Codes: G11B 5/09 Digital recording

Abstract

It relates to a hybrid recording apparatus using. The recording apparatus includes a magnetic disk medium for recording and reading data by a magnetic head, a nonvolatile memory in which a write cache area is allocated, a cache control unit for temporarily loading write data, which is recorded on the magnetic disk medium, into the write cache area in accordance with a write request from a higher-level apparatus. A memory allocation management unit stores memory management information in the magnetic disk medium for management thereof, the memory management information representing an allocated position of the write cache area in the nonvolatile memory.

Claims

1. A recording apparatus comprising:

a magnetic disk medium for recording and reading data by a magnetic head;

a nonvolatile memory in which a write cache area is allocated;

a cache control unit for temporarily loading write data, which is recorded on the magnetic disk medium, into the write cache area in accordance with a write request from a higher-level apparatus;

a memory allocation management unit for storing memory management information in the magnetic disk medium for management thereof, the memory management information representing an allocated position of the write cache area in the nonvolatile memory; and

a memory allocation changing unit for changing the memory management information to cyclically shift the write cache area in units of a predetermined address size that is smaller than an erase unit of the nonvolatile memory, whenever the write cache area is emptied.

2. The recording apparatus according to claim 1, wherein the memory allocation management unit registers an area head address of the write cache area in the memory management information for management thereof, and

the memory allocation changing unit shifts the area head address registered in the memory management information in units of the predetermined address size.

3. The recording apparatus according to claim 1, wherein when power is turned on, the memory allocation management unit reads out the memory management information from the magnetic disk medium and places the read-out memory management information in a volatile memory.

4. The recording apparatus according to claim 3, wherein when the memory management information is changed in the volatile memory, the memory allocation management unit writes the changed memory management information onto the magnetic disk medium and executes the management by using the changed memory management information on condition that the write of the changed memory management information onto the magnetic disk medium has succeeded.

5. The recording apparatus according to claim 1, wherein the memory allocation changing unit changes the memory management information to cyclically shift the write cache area in units of one sector size on the magnetic disk medium.

6. The recording apparatus according to claim 1, wherein the memory allocation changing unit changes the memory management information to cyclically shift the write cache area in units of one word on the magnetic disk medium.

7. The recording apparatus according to claim 1, wherein the cache control unit writes all the write cache data in the write cache area onto the magnetic disk medium to empty the write cache area when a predetermined command is received from the higher-level apparatus, when the write cache area becomes full of the write cache data, or when a vacant capacity of the write cache area is reduced to a predetermined value or less.

8. The recording apparatus according to claim 1, wherein the memory allocation changing unit forcibly writes all the write cache data in the write cache area onto the magnetic disk medium to empty the write cache area when the write cache data in the write cache area allocated in the nonvolatile memory is not moved after a predetermined time has lapsed or after the number of write requests has reached a predetermined value.

9. A recording apparatus comprising:

a magnetic disk medium for recording and reading data by a magnetic head;

a nonvolatile memory in which a read cache area is allocated;

a cache control unit for temporarily loading read data, which is read from the magnetic disk medium, into the read cache area in accordance with a read request from a higher-level apparatus;

a memory allocation management unit for storing memory management information in the magnetic disk medium for management thereof, the memory management information representing an allocated position of the read cache area in the nonvolatile memory; and

a memory allocation changing unit for changing the memory management information to cyclically shift the read cache area in units of a predetermined address size that is smaller than an erase unit of the nonvolatile memory, whenever a part or the whole of read cache data in the read cache area allocated in the nonvolatile memory is invalidated and the part or the whole of the read cache area is emptied.

10. The recording apparatus according to claim 9, wherein the memory allocation management unit registers an area head address of the read cache area in the memory management information for management thereof, and

the memory allocation changing unit shifts the area head address registered in the memory management information in units of the predetermined address size.

11. The recording apparatus according to claim 9, wherein when power is turned on, the memory allocation management unit reads out the memory management information from the magnetic disk medium and places the read-out memory management information in a volatile memory.

12. The recording apparatus according to claim 11, wherein when the memory management information is changed in the volatile memory, the memory allocation management unit writes the changed memory management information onto the magnetic disk medium and executes the management by using the changed memory management information on condition that the write of the changed memory management information onto the magnetic disk medium has succeeded.

13. The recording apparatus according to claim 9, wherein the memory allocation changing unit changes the memory management information to cyclically shift the read cache area in units of one sector size on the magnetic disk medium.

14. The recording apparatus according to claim 9, wherein the memory allocation changing unit changes the memory management information to cyclically shift the read cache area in units of one word on the magnetic disk medium.

15. The recording apparatus according to claim 9, wherein the cache control unit invalidates all the read cache data in the read cache area to empty the read cache area when a predetermined command is received from the higher-level apparatus.

16. A control circuit for a recording apparatus comprising a magnetic disk medium for recording and reading data by a magnetic head;

and

a nonvolatile memory in which a write cache area and a read cache area are allocated, the control circuit comprising;

a cache control unit for temporarily loading write data, which is recorded on the magnetic disk medium, into the write cache area in accordance with a write request from a higher-level apparatus, and for temporarily loading read data, which is read from the magnetic disk medium, into the read cache area in accordance with a read request from the higher-level apparatus;

a memory allocation management unit for storing memory management information on the magnetic disk medium for management thereof, the memory management information representing respective allocated positions of the read cache area and the write cache area in the nonvolatile memory;

a first memory allocation changing unit for changing the memory management information to cyclically shift the write cache area in units of a predetermined address size that is smaller than an erase unit of the nonvolatile memory, whenever write cache data in the write cache area allocated in the nonvolatile memory is all written onto the magnetic disk medium and the write cache area is emptied; and

a second memory allocation changing unit for changing the memory management information to cyclically shift the read cache area in units of a predetermined address size that is smaller than an erase unit of the nonvolatile memory, whenever read cache data in the read cache area allocated in the nonvolatile memory is all invalidated and the read cache area is emptied.

17. The recording apparatus according to claim 16, wherein the memory allocation management unit registers respective area head addresses of the write cache area and the write cache area in the memory management information for management thereof, and

the memory allocation changing unit shifts the area head addresses registered in the memory management information in units of the predetermined address size.

18. The recording apparatus according to claim 16, wherein when power is turned on, the memory allocation management unit reads out the memory management information from the magnetic disk medium and places the read-out memory management information in a volatile memory.

19. The recording apparatus according to claim 18, wherein when the memory management information is changed in the volatile memory, the memory allocation management unit writes the changed memory management information onto the magnetic disk medium and executes the management by using the changed memory management information on condition that the write of the changed memory management information onto the magnetic disk medium has succeeded.

20. The recording apparatus according to claim 16, wherein each of the first memory allocation changing unit and the second memory allocation changing unit changes the memory management information to cyclically shift the write cache area or the read cache area in units of one sector size or one word on the magnetic disk medium.