Appliance, including a flash memory, that is robust under power failure
First Claim
1. A method of operating an appliance that includes a host device and a memory unit, the memory unit including a nonvolatile memory, the method comprising the steps of:
- (a) providing a volatile cache memory for caching data prior to writing said data to the nonvolatile memory; and
(b) upon interruption of power to the memory unit, selectively writing at least a portion of said data of only one data class then cached in said volatile cache memory to the nonvolatile memory, said one data class being selected from the group consisting of system data and user data.
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0 Petitions
Accused Products
Abstract
An appliance that includes a host device and a memory unit with a primary memory, and a method of operating the appliance. According to one aspect of the appliance, the primary memory is nonvolatile and the memory unit also includes a volatile memory a power sensor and a controller. When the power sensor detects interruption of power to the memory unit, the controller copies data selectively from the volatile memory to the primary memory. Power for this copying is provided by a secondary power source such as a battery or a capacitor. According to another aspect of the appliance, the appliance includes primary and secondary power sources, and the memory unit also includes a charge pump whose functions include both boosting power from the primary source for the primary memory and charging the secondary source.
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Citations
26 Claims
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1. A method of operating an appliance that includes a host device and a memory unit, the memory unit including a nonvolatile memory, the method comprising the steps of:
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(a) providing a volatile cache memory for caching data prior to writing said data to the nonvolatile memory; and (b) upon interruption of power to the memory unit, selectively writing at least a portion of said data of only one data class then cached in said volatile cache memory to the nonvolatile memory, said one data class being selected from the group consisting of system data and user data. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method of operating an appliance that includes a host device and a memory unit, the memory unit including a nonvolatile memory, the method comprising the steps of:
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(a) providing a volatile cache memory for caching data prior to writing said data to the nonvolatile memory; and (b) upon interruption of power to the memory unit, selectively writing only a portion of said data then cached in said volatile cache memory to the nonvolatile memory. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A method of operating an appliance that includes a host device and a memory unit, the memory unit including a nonvolatile memory, the method comprising the steps of:
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(a) providing a volatile memory for storing only system data; and (b) only upon interruption of power to the memory unit, selectively writing at least a portion of said system data then stored in said volatile memory to the nonvolatile memory.
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16. An appliance comprising:
(a) a memory unit including; (i) a nonvolatile memory; (ii) a volatile cache memory for caching data prior to writing said data to said nonvolatile memory; (iii) a power sensor for receiving and detecting power supplied by a primary power source external to said memory unit, said power being for powering said memory unit; and (iv) a controller for, upon receiving an indication from said power sensor of an interruption of said power, selectively writing at least a portion of said data of only one data class then cached in said volatile cache memory to said nonvolatile memory, said one data class being selected from the group consisting of system data and user data. - View Dependent Claims (17)
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18. An appliance comprising:
(a) a memory unit including; (i) a nonvolatile memory; (ii) a volatile cache memory for caching data prior to writing said data to said nonvolatile memory; (iii) a power sensor for receiving and detecting power supplied by a primary power source external to said memory unit, said power being for powering said memory unit; and (iv) a controller for, upon receiving an indication from said power sensor of an interruption of said power, selectively writing only a portion of said data then cached in said volatile cache memory to said nonvolatile memory.
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19. An appliance comprising:
(a) a memory unit including; (i) a nonvolatile memory; (ii) a volatile memory for storing only system data; (iii) a power sensor for receiving and detecting power supplied by a primary power source external to said memory unit, said power being for powering said memory unit; and (iv) a controller for, only upon receiving an indication from said power sensor of an interruption of said power, selectively writing at least a portion of said system data then stored in said volatile memory to said nonvolatile memory.
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20. A method of operating an appliance that includes a host device and a memory unit, the memory unit including a nonvolatile memory, the method comprising the steps of:
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(a) providing a volatile memory for storing data; and (b) upon interruption of power to the memory unit, writing to the nonvolatile memory at least a portion of said data of only one data class then stored in said volatile memory, said one data class being selected from the group consisting of system data and user data. - View Dependent Claims (21, 22)
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23. A method of operating an appliance that includes a host device and a memory unit, the memory unit including a nonvolatile memory, the method comprising the steps of:
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(a) providing a volatile memory for storing system data; (b) only upon interruption of power to the memory unit, selectively writing at least a portion of said system data then stored in said volatile memory to the nonvolatile memory; wherein said at least portion of said data includes file allocation data.
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24. A method of operating an appliance that includes a host device and a memory unit, the memory unit including a nonvolatile memory, the method comprising the steps of:
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(a) providing a volatile memory for storing system data; (b) only upon interruption of power to the memory unit, selectively writing at least a portion of said system data then stored in said volatile memory to the nonvolatile memory; wherein said at least portion of said data includes a copy of a memory buffer that is used by the host device to accumulate user data.
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25. A method of operating an appliance that includes a host device and a memory unit, the memory unit including a nonvolatile memory, the method comprising the steps of:
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(a) providing a volatile memory for storing system data; (b) only upon interruption of power to the memory unit, selectively writing at least a portion of said system data then stored in said volatile memory to the nonvolatile memory; wherein said at least portion of said data includes a description of a status of the host device.
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26. A method of operating an appliance that includes a host device and a memory unit, the memory unit including a nonvolatile memory, the method comprising the steps of:
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(a) providing a volatile memory for storing system data; (b) only upon interruption of power to the memory unit, selectively writing at least a portion of said system data then stored in said volatile memory to the nonvolatile memory; wherein said at least portion of said data includes an identification of an interrupted operation.
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Specification