Importance

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Abstract

The present invention provides a method and apparatus in a data storage device of a data storage system under the control of a microprocessor for preventing a microprocessor stall upon the occurrence of a power failure during read/write operations. During normal operations, files are written to a first storage area of the data storage device where a first flag associated with each file is set when the writing of the respective file has successfully completed. Upon the occurrence of a power failure, a data storage device initialization routine is commenced upon reboot of the microprocessor. During initialization, an analysis phase is begun to generate sequences of events for at least those files not having the first flag set. The events comprise memory operations and associated data and are each re-executable upon interruption of its execution and before execution of another event without modifying results of a previous execution of the respective event. The events generated are then written to an event storage area in the data storage device. During an execution phase of the data storage device initialization, the events are retrieved and executed by the microprocessor to cause the files having at least the first flag set to be written in a compacted manner to storage locations in a second storage area of the memory device to maintain the integrity of those files. Subsequently, the first storage area of the memory device is erased to provide additional storage space for the writing of new files to the memory device. If a power failure or system failure occurs during the two-phase initialization process, the process is re-started generally at the point where it was interrupted so as not to leave the data storage device in a partially compacted, and hence, a potentially inconsistent state.

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First Claim