Sandisk Corporation

Zilog, Inc.

Daniel L Auclair

Robert D Norman

Daniel C Guterman

Sanjay Mehrotra

John S Mangan

Jeffrey G Craig

Eli Harari

Anthony J Knights

Johnny H Chen

Leon Malmed

Soft errors occur during normal use of a solid-state memory such as EEPROM or Flash EEPROM. A soft error results from the programmed threshold voltage of a memory cell being drifted from its originally intended level. The error is initially not readily detected during normal read until the cumulative drift becomes so severe that it develops into a hard error. Data could be lost if enough of these hard errors swamps available error correction codes in the memory. A memory device and techniques therefor are capable of detecting these drifts and substantially maintaining the threshold voltage of each memory cell to its intended level throughout the use of the memory device, thereby resisting the development of soft errors into hard errors.

Soft errors handling in EEPROM devices

Memory card reader

Solid-state flash electrically erasable and programmable read-only-memory ('flash EEPROM') system is combined with a rotating disk drive memory to provide mass program and data storage in a computer system. A common memory controller directs system generated memory addresses in a disk format to either the EEPROM system or disk memory. The blocks of data handled by the EEPROM system have the same size and other attributes as sectors of data handled by the disk system, thereby making it transparent to the computer system processor as to whether it is accessing the EEPROM or disk portion of the storage system. A particular program or data file may then be stored in the portion of the memory system best suited to handle it, and thus take advantage of the different features and characteristics of EEPROM and magnetic media disk memory.

Mass computer storage system having both solid state and rotating disk

Growing community of inventors

Mountain View, CA, United States of America

Daniel L Auclair