Patent ID: 6115785
Filing Date: 2000-09-05
Classification: G06F,G11C

Abstract:
A nonvolatile storage system having nonvolatile memory, the storage system being coupled to an external digital system for storing binary information therefor in the nonvolatile memory, the external digital system including means for generating a plurality of logical block addresses for use in storing or reading data, the storage system comprising:a. a volatile memory device having a plurality of volatile memory locations each of which is uniquely addressable by one of the logical block addresses, and wherein each of the volatile memory locations is configured to store a physical block address without requiring the storage of a corresponding logical block address;b. one or more nonvolatile memory devices having a plurality of nonvolatile data blocks, each block being selectively programmable and erasable, being uniquely addressable by one of the physical block addresses, and having associated therewith at least one flag stored indicative of the status of the block; andc. a controller for receiving a block of data from the external digital system to be stored in the one or more nonvolatile memory devices, for receiving a target logical block address from the external system, for identifying a free block within the nonvolatile data blocks having no data stored therein, for storing the physical block address of the free block in the volatile memory location that corresponds to the target logical block address, and for periodically erasing all blocks of the nonvolatile memory devices having flags which are set, whereby an erase cycle is not needed each time the external system writes to the storage device, wherein the at least one flag associated with the block is copied from the nonvolatile memory devices to the volatile memory locations.