University of Alabama

Sandisk Technologies Inc.

Western Digital Technologies, Inc.

Biswajit Ray

Changyuan Chen

Mohan Dunga

Aleksandar Milenkovic

Gerrit Jan Hemink

Md Raquibuzzaman

Preeti Kumari

Abuzer Azo Dogan

Himanshu Hemant Naik

Nian Niles Yang

Peter Rabkin

Grishma Shah

Anubhav Khandelwal

Philip David Reusswig

Joanna Lai

Chris Yip

Bijesh Rajamohanan

M Tauhidur Rahman

Aleksander Milenkovic

Umeshwarnath Surendranathan

Matchima Buddhanoy

Levi Scott Davies

A system for performing sanitization of multi-level cell (MLC) memory has a memory controller configured to read and buffer at least a first page of MLC memory that shares MLCs with at least a second page. The memory controller sanitizes the second page by performing at least one write operation to adjust the charge levels in the MLCs so that each bit of the second page is forced to the same value or to a value that mirrors the value of another bit of the same cell. Thus, for multiple pages sharing the same MLCs, the data of at least one page can be sanitized while the data of at least one other page is retained. Such sanitizing can be achieved without having to perform an erase operation, thereby helping to prevent or reduce memory degradation.

Systems and methods for sanitization of multi-level cell (MLC) memory

A system for improving radiation tolerance of memory senses an amount of radiation exposure and, based on the sensed amount of radiation exposure, determines whether to perform one or more techniques for mitigating the effects of the radiation exposure. As an example, the system may perform a data refresh operation by re-writing data that has been corrupted by radiation, or the system may adjust the reference voltage used to read memory cells. In another example, the system may perform a fault repair operation by re-programming cells that have erroneously transitioned from a program state to an erase state. The system may selectively perform different radiation-mitigation techniques in a tiered approach based on the sensed amount of radiation in order to limit the adverse effects of the more invasive techniques.

Systems and methods for improving radiation tolerance of memory

An exemplary random number generation system leverages the r includes at least one solar power panel of a solar power system, at least one sensor and a random number generator. The sensor senses one or more output parameters (e.g., voltage or current) from the solar power system and provides the sensed parameter to the random number generator, which uses the sensed parameter to generate a number that is truly random (i.e., is not deterministic). As an example, the random number generator may receive multiple samples of the measured parameter and generate a random number based on a difference of the multiple samples. If desired, the random number generator may include an algorithm to remove biasing in the random number.

Random number generation systems and methods

A memory authentication system initiates various memory operations on a memory chip and then assesses the performance of the memory chip in performing such operations in an attempt to identify a signature in the chip's performance that can be used to identify the chip's source. As an example, a partial erase operation may be performed on programmed memory cells in order to drain some charge from the cells but allowing some charge to remain in the cells. Due to process variations during manufacturing, charge should drain from the cells at different rates such that some of the cells may flip to an erase state while other cells remain in a program state. The pattern of bit flips defines a unique signature that may be used to identify the chip's manufacturing source (e.g., the foundry at which the chip was manufactured).

Systems and methods for identifying counterfeit memory

A radiation detection system may include a mobile device having a flash memory. The device may monitor various characteristics of the flash memory to determine when damage to the flash memory has occurred from radiation exposure. The device may associate damage to the flash memory with a radiation dose, and determine a level of radiation to which the memory, and thus the device, has been exposed. The device also may determine a length of time and locations where the radiation exposure has occurred. If the device determines that the level of radiation exposure exceeds a threshold associated with a safe level of radiation exposure for a human user, the device may generate an alert to the user.

Systems and methods for sensing radiation using flash memory

A traffic monitoring system has a controller and sensors placed in or on roads such that vehicles pass over or near the sensors, thereby casting shadows on the sensors as they pass. The sensors may be configured to detect the shadows, and a controller may be configured to determine any of a variety of information about the passing vehicles based on the detected shadows. For example, the controller may count the number of vehicles that pass, determine a speed of each passing vehicle, and determine a length of each passing vehicle. The sensors can be relatively inexpensive so that a relatively large number of sensors can be used to monitor a large area at a relatively low cost. In some embodiments, solar cells are used to power the sensors, and if desired, the solar cells may be used as the sensors for detecting the shadows of the vehicles being monitored.

Systems and methods for monitoring vehicular traffic

A system for testing memory includes logic that is configured to perform various normal memory operations (e.g., erase, read and write operations) on a memory device and to determine operational parameters associated with the memory operations. As an example, the amount of time to perform one or more memory operations may be measured, a number of errors resulting from the memory operations may be determined, or a number of memory cells storing noisy bits may be identified. One or more of the operational parameters may then be analyzed to determine whether they are in a range expected for counterfeit or defective memory. If so, the logic determines that the memory under test is counterfeit or defective and provides a notification about such determination.

Systems and methods for detecting counterfeit or defective memory

Systems and methods for improving radiation tolerance of three-dimensional flash memory

A random number generation system may generate one or more random numbers based on the repeated programming of a memory, such as a flash memory. As an example, a control system may repeatedly store a sequence to a block of flash memory to force a plurality of cells into a random state such that, at any given instant, the values in the cells may be random. The control system may identify which of the cells contain random values and then generate based on the identified values a number that is truly random.

A system performs analog memory sanitization by forcing voltage levels in memory cells to substantially the same voltage level so that they are indistinguishable regardless of the data that has been previously stored in the cells. In some embodiments, a special programming operation for sanitizing a plurality of memory cells forces the charge in the cells to approximately the same voltage level by increasing the voltage level of all cells regardless of the data currently stored in the cells. As an example, each cell may be programmed to a logical high bit value (e.g., a '0') by increasing the charge in each cell to a voltage level that is greater than the voltage level for writing the same logical bit value in a normal programming operation. Thus, after the programming operation is performed, the voltage levels of cells storing one logical bit value (e.g., a '0') prior to the programming operation may be indistinguishable from voltage levels of cells storing a different logical bit value (e.g., a &#x201c;1&#x201d;) prior to the programming operation.

Systems and methods for runtime analog sanitization of memory

A memory system performs analog sanitization of memory using a partial programming operation to overwrite existing data taking into account the relative voltage levels in the memory cells. By taking into account the relative voltage levels, the timing of a partial programming operation can be controlled to provide matched voltage levels in the memory cells so that conventional computer forensic techniques for data recovery are ineffective.

Growing community of inventors

Huntsville, AL, United States of America

Biswajit Ray