US 8,266,398 B2 · Method and apparatus for preserving memory contents during a power outage

Abstract

A method and apparatus for preserving contents of a volatile memory when a main (e.g., AC) power source is disconnected. The apparatus comprises flash memory, a controller for writing to the flash memory and a temporary power source. The temporary power source may be a relatively low power battery or supercapacitor. The apparatus is removably attached to a computing device (e.g., via a USB port). When main power of the device is disconnected, the temporary power source provides power for the apparatus, the volatile memory containing data to be safeguarded, and sufficient processing resources to transfer the data. For example, an auxiliary processor may be powered (instead of a relatively high-power processor) or just one core of a multi-core processor. Data are written to the apparatus and can be recovered when main power is reconnected. Or, the apparatus may be detached and attached to a different device for data recovery.

Claims21

Dependent claims

A computing device configured to copy data from volatile memory to non-volatile memory during a power outage, the computing device comprising:

a multi-core processor configured to execute program code;
volatile memory configured to temporarily store data during use by the processor while executing the program code;
non-volatile flash memory;
and
a temporary power source configured to power the processor, the volatile memory and the flash memory when a primary power source is unavailable;
wherein, if the primary power source is available, the computing device is configured to store the data to the volatile memory without writing the data to the flash memory and to receive one or more indications from an application executing on the multi-core processor, each indication indicating one or more memory ranges for the application in the volatile memory and indicating that data in the one or more memory ranges is to be saved to the flash memory if the primary power source is unavailable, and
otherwise, if the primary power source is unavailable, the computing device is configured to copy data for the application from the volatile memory to the flash memory by copying memory ranges for the application in the volatile memory for which an indication was received.

4 more elements

A method of protecting data during loss of a computing device's main power, the method comprising:

receiving a removable connection to the computing device of an apparatus comprising flash memory and an alternative power source;
operating the computing device in a normal mode, in which data are temporarily stored in a volatile memory of the computing device for transfer to secondary storage, wherein during the normal mode, the data is not stored to the flash memory, and wherein, during the normal mode, the computing device receives one or more indications from an application executing on the computing device, each indication indicating one or more memory ranges for the application in the volatile memory and indicating that data in the one or more memory ranges is to be saved to the flash memory responsive to failure of the main power;
detecting failure of the main power;
upon detection of the main power failure, operating the computing device in a transition mode of operation, said transition mode characterized by:
powering a selected subset of components of the computing device from the alternative power source;
and
using the selected subset of components to copy data for the application from the volatile memory of the computing device to the flash memory by copying memory ranges for the application in the volatile memory that the application indicated are to be saved to the flash memory responsive to failure of the main power source.

4 more elements

Dependencies are inferred from the claim text.

Method and apparatus for preserving memory contents during a power outage

Life of this patent

Method and apparatus for preserving memory contents during a power outage

Life of this patent

Abstract

Claims21