Sandisk Corporation

Other

Sandisk Technologies Inc.

Western Digital Corporation

Karl M J Lofgren

Robert D Norman

Anil K Gupta

Sanjay Mehrotra

Gregory B Thelin

Jeffrey Donald Stai

A memory system includes an array of solid state memory devices which are in communication with and under the control of a controller module via a device bus with very few lines. This forms an integrated-circuit mass storage system which is contemplated to replace a mass storage system such as a disk drive memory in a computer system. Command, address and data information are serialized into component strings and multiplexed before being transferred between the controller module and the array of memory devices. The serialized information are is accompanied by a control signal to help sort out the multiplexed components. Each memory device in the array is mounted on a multi-bit mount and assigned an array address by it an array mount. An A memory device is selected by an appropriate address broadcast over the device bus, without requiring the usual dedicated select signal. A reserved array particular mount multi-bit configuration is used to unconditionally select the device mounted thereon. A reserved predefined address broadcast over the device bus deselects all previously selected memory devices. Read performance is enhanced by a read streaming technique in which while a current chunk of data is being serialized and shifted out of the memory subsystem devices to the controller module, the controller module is also setting up the address for the next chunk of data to begin to address the memory system.

Device and method for controlling solid-state memory system

A memory system includes an array of solidstate memory devices which are in communication with and under the control of a controller module via a device bus with very few lines. This forms an integrated-circuit mass storage system which is contemplated to replace a mass storage system such as a disk drive memory in a computer system. Command, address and data information are serialized into component strings and multiplexed before being transferred between the controller module and the array of memory devices. The serialized information are is accompanied by a control signal to help sort out the multiplexed components. Each memory device in the array is mounted on a multi-bit mount and assigned an array address by it an array mount. An A memory device is selected by an appropriate address broadcast over the device bus, without requiring the usual dedicated select signal. A reserved array particular mount multi-bit configuration is used to unconditionally select the device mounted thereon. A reserved predefined address broadcast over the device bus deselects all previously selected memory devices. Read performance is enhanced by a read streaming technique in which while a current chunk of data is being serialized and shifted out of the memory subsystem devices to the controller module, the controller module is also setting up the address for the next chunk of data to begin to address the memory system.

A mass storage system made of flash electrically erasable and programmable read only memory ('EEPROM') cells organized into blocks, the blocks in turn being grouped into memory banks, is managed to even out the numbers of erase and rewrite cycles experienced by the memory banks in order to extend the service lifetime of the memory system. Since this type of memory cell becomes unusable after a finite number of erase and rewrite cycles, although in the tens of thousands of cycles, uneven use of the memory banks is avoided so that the entire memory does not become inoperative because one of its banks has reached its end of life while others of the banks are little used. Relative use of the memory banks is monitored and, in response to detection of uneven use, have their physical addresses periodically swapped for each other in order to even out their use over the lifetime of the memory.

Wear leveling techniques for flash EEPROM systems

A mass storage system made of flash electrically erasable and programmable read only memory (&ldquo;EEPROM&rdquo;) cells organized into blocks, the blocks in turn being grouped into memory banks, is managed to even out the numbers of erase and rewrite cycles experienced by the memory banks in order to extend the service lifetime of the memory system. Since this type of memory cell becomes unusable after a finite number of erase and rewrite cycles, although in the tens of thousands of cycles, uneven use of the memory banks is avoided so that the entire memory does not become inoperative because one of its banks has reached its end of life while others of the banks are little used. Relative use of the memory banks is monitored and, in response to detection of uneven use, have their physical addresses periodically swapped for each other in order to even out their use over the lifetime of the memory.

A memory system includes an array of solid-state memory devices are in communication with and under the control of a controller module via a device bus with very few lines. This forms an integrated-circuit mass storage system which is contemplated to replace a mass storage system such as a disk drive memory in a computer system. Command, address and data information are serialized into component strings and multiplexed before being transferred between the controller module and the array of memory devices. The serialized information are accompanied by a control signal to help sort out the multiplexed components. Each memory device in the array is assigned an array address by an array mount. An memory device is selected by an appropriate address broadcast over the device bus, without requiring the usual dedicated select signal. A reserved array mount configuration is used to unconditionally select the device mounted. A reserved address broadcast over the device bus deselects all previously selected memory devices. Read performance is enhanced by a read streaming technique in which while a current chunk of data is being serialized and shifted out of the memory subsystem to the controller module, the controller module is also setting up the address for the next chunk of data to begin to address the memory system.

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Newport Beach, CA, United States of America

Karl M J Lofgren