Sandisk Corporation

Sundisk Corporation

Sandisk Technologies Inc.

Other

Stephen Jeffrey Gross

Daniel C Guterman

Geoffrey Steven Gongwer

Sanjay Mehrotra

Eli Harari

Shahzad Khalid

Robert D Norman

George Samachisa

Winston Lee

Bryan John Mee

John S Mangan

Shazad Khalid

Claudio R Dacal

The quality of data stored in a memory system is assessed by different methods, and the memory system is operated according to the assessed quality. The data quality can be assessed during read operations. Subsequent use of an Error Correction Code can utilize the quality indications to detect and reconstruct the data with improved effectiveness. Alternatively, a statistics of data quality can be constructed and digital data values can be associated in a modified manner to prevent data corruption. In both cases the corrective actions can be implemented specifically on the poor quality data, according to suitably chosen schedules, and with improved effectiveness because of the knowledge provided by the quality indications. These methods can be especially useful in high-density memory systems constructed of multi-level storage memory cells.

Increasing the effectiveness of error correction codes and operating multi-level memory systems by using information about the quality of the stored data

Tracking cells are used in a memory system to improve the read process. The tracking cells can provide an indication of the quality of the data and can be used as part of a data recovery operation if there is an error. The tracking cells provide a means to adjust the read parameters to optimum levels in order to reflect the current conditions of the memory system. Read operations are performed on the tracking cells, where threshold voltages of physical states of the tracking cells are further apart than threshold voltages of physical states of non-tracking cells. Based on the read operations, an extent to which the tracking cells are errored is determined.

Tracking cells for a memory system

Tracking cells are used in a memory system to improve the read process. The tracking cells can provide an indication of the quality of the data and can be used as part of a data recovery operation if there is an error. The tracking cells provide a means to adjust the read parameters to optimum levels in order to reflect the current conditions of the memory system. Additionally, some memory systems that use multi-state memory cells will apply rotation data schemes to minimize wear. The rotation scheme can be encoded in the tracking cells based on the states of multiple tracking cells, which is decoded upon reading.

Data recovery in a memory system using tracking cells

A portion of data stored in a non-volatile memory may be found to be corrupted when it is read. Where parity data is generated from portions of data and the parity data is stored with the portions of data, the corrupted data may be reconstructed from the parity data and uncorrupted portions of data.

Method of storing downloadable firmware on bulk media

A portion of data stored in a non-volatile memory may be found to be corrupted when it is read. Where parity data is generated from portions of data and parity data is stored with the portions of data, the corrupted data may be reconstructed from the parity data and uncorrupted portions of data.

Storing downloadable firmware on bulk media

The quality of data stored in a memory system is assessed by different methods, and the memory system is operated according to the assessed quality. The data quality can be assessed during read operations. Subsequent use of an Error Correction Code can utilize the quality indications to detect and reconstruct the data with improved effectiveness. Alternatively, a statistics of data quality can be constructed and digital data values can be associated in a modified manner to prevent data corruption. In both cases the corrective actions can be implemented specifically on the poor quality data, according to suitably chosen schedules, and with improved effectiveness because of the knowledge provided by the qualify indications. These methods can be especially useful in high-density memory systems constructed of multi-level storage memory cells.

Methods and apparatus for transforming data into a format which may be efficiently stored in a non-volatile memory are disclosed. According to one aspect of the present invention, a method for storing information of a first data format in a memory system includes generating statistics associated with the first data format, and transforming the information from the first data format to a second data format using the statistics. Once the information is transformed into the second data format, the information is stored into a memory. Storing the information in the second data format in the memory includes storing an identifier that identifies a transformation used to transform the information to the second data format. In one embodiment, costs associated with storing the information in the second data format are less than or equal to costs associated with storing the information in the first data format.

Symbol frequency leveling in a storage system

An arm and safety switch for ammunition rounds, such as a 120 mm multipurpose tank round, senses launch detonation pressure. The switch will not arm the projectile if the pressure detected is less than or equal to a first predetermined pressure characteristic of a misfire, and will arm if the detected pressure is greater than or equal to a second predetermined pressure characteristic of a successful launch. An efficient, reliable method and mechanism operate to discriminate between successful and unsuccessful projectile launch and use that information to arm or not arm the projectile.

Arm and safety switch

A memory system having a two dimensional array of EEPROM or Flash EEPROM cells is addressable by rows and columns. A word line is connected to the control gates of all the cells in each row, an erase line is connected to all the erase gates of each sector of cells, and a pair of bit lines are connected respectively to all the sources and drains of each column of cells. The memory system incorporates a word line current detector and an erase line current detector in addition to the usual bit line current detectors. The leakage current of each of the lines are measured after predetermined memory events such as program or erase operations. When a defective row or column is detected, it is electrically isolated from other columns by programming and is mapped out and replaced. Data recovery schemes include reading a defective column by a switched-memory-source-drain technique.

Latent defect handling in EEPROM devices

In a mixed data encoding scheme for programming data into a flash sector of a flash EEPROM system, a method for determining which data encoding scheme has been used for programming the retrieved data involves examining whether an error correction code of the data indicates an error.

Growing community of inventors

Cupertino, CA, United States of America

Stephen Jeffrey Gross