DATA STORAGE DEVICE AND METHOD

• US 20100299558A1
• Filed: 05/12/2010
• Published: 11/25/2010
• Est. Priority Date: 05/19/2009
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Hayashi, Satoshi, Oota, Yusuke, TOJO, Mihoko, Kobayashi, Hidefumi, Umezawa, Keiichi
• Granted Patent: US 8,078,908 B2
• Time in Patent Office: Days
• US Class Current: 714/14
• CPC Class Codes: G06F 11/1441 Resetting or repowering
• CPC Class Codes: G06F 12/0866 for peripheral storage systems, e.g. disk cache
• CPC Class Codes: G06F 21/77 in smart cards
• CPC Class Codes: G06F 21/805 using a security table for the storage sub-system
• CPC Class Codes: G06F 21/81 by operating on the power supply, e.g. enabling or disabling power-on, sleep or resume operations
• CPC Class Codes: G06F 2221/2143 Clearing memory, e.g. to prevent the data from being stolen
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

An apparatus includes a cache memory for storing user data and control information of the apparatus, a nonvolatile memory and a processor for executing a process including when the power failure occurs, saving the user data and the control information stored in the cache memory into the nonvolatile memory, when the power failure recovers, restoring the data stored in the nonvolatile memory into the cache memory, and erasing the data stored in the nonvolatile memory after restoring the data into the cache memory and when another power failure occurs during erasing the data stored in the nonvolatile memory, erasing the control information stored in the nonvolatile memory if the control information is remained in the nonvolatile memory and saving, into the nonvolatile memory, the updated control information stored in the cache memory and the user data which has been erased from the nonvolatile memory.

Claims

1. A data storage apparatus, comprising:

a cache memory for storing data including user data and control information of the apparatus;

a nonvolatile memory;

a power supply for supplying an instant power after an occurrence of a power failure; and

a processor for executing a process including;

when the power failure occurs, saving the user data and the control information stored in the cache memory into the nonvolatile memory by using the instant power;

when the power failure recovers, restoring the data stored in the nonvolatile memory into the cache memory, updating the managing information stored in the cache memory, and erasing the data stored in the nonvolatile memory after restoring the data into the cache memory; and

when another power failure occurs during erasing the data stored in the nonvolatile memory, stopping the erasing, erasing the control information stored in the nonvolatile memory by using the instant power if the control information is remained in the nonvolatile memory and saving, into the nonvolatile memory, the updated control information stored in the cache memory and the user data which has been erased from the nonvolatile memory.

2. The data storage apparatus according to claim 1, further comprising management table for storing address information of the control information of the nonvolatile memory and the size of the control information.

3. The data storage apparatus according to claim 1, wherein the process include determining whether the control information stored in the nonvolatile memory is eased by using the management table.

4. A data storage method for controlling a data storage apparatus, including a cache memory for storing data including user data and control information of the apparatus;

a nonvolatile memory;

a power supply for supplying an instant power after an occurrence of a power failure, the method, comprising;

when the power failure occurs, saving the user data and the control information stored in the cache memory into the nonvolatile memory by using the instant power;

when the power failure recovers, restoring the data stored in the nonvolatile memory into the cache memory, updating the managing information stored in the cache memory, and erasing the data stored in the nonvolatile memory after restoring the data into the cache memory; and

when another power failure occurs during erasing the data stored in the nonvolatile memory, stopping the erasing, erasing the control information stored in the nonvolatile memory by using the instant power if the control information is remained in the nonvolatile memory and saving, into the nonvolatile memory, the updated control information stored in the cache memory and the user data which has been erased from the nonvolatile memory.

5. The data storage method according to claim 4, wherein the data storage apparatus further including management table for storing address information of the control information of the nonvolatile memory and the size of the control information,

the method further comprising determining whether the control information stored in the nonvolatile memory is eased by using the management table.

6. A non-transitory computer readable medium storing a management program for controlling a data storage apparatus, including a cache memory for storing data including user data and control information of the apparatus;

a nonvolatile memory;

a power supply for supplying an instant power after an occurrence of a power failure, the method, comprising;

when the power failure occurs, saving the user data and the control information stored in the cache memory into the nonvolatile memory by using the instant power;

when the power failure recovers, restoring the data stored in the nonvolatile memory into the cache memory, updating the managing information stored in the cache memory, and erasing the data stored in the nonvolatile memory after restoring the data into the cache memory; and

when another power failure occurs during erasing the data stored in the nonvolatile memory, stopping the erasing, erasing the control information stored in the nonvolatile memory by using the instant power if the control information is remained in the nonvolatile memory and saving, into the nonvolatile memory, the updated control information stored in the cache memory and the user data which has been erased from the nonvolatile memory.

7. The non-transitory computer readable medium according to claim 6, wherein the data storage apparatus further including management table for storing address information of the control information of the nonvolatile memory and the size of the control information,

the method further comprising determining whether the control information stored in the nonvolatile memory is eased by using the management table.