Abstract: A memory device generates one or more read reference voltages rather than being explicitly supplied with each read reference voltage from an external host controller. The technique involves providing a command to the memory device that causes a reading of a set of storage elements by the memory device using a reference voltage which is different than a reference voltage used in a previous reading, where the new read reference value is not explicitly set outside the memory device. In one implementation, the memory device is provided with an initial reference voltage and a step size for generating additional reference voltages. The technique can be used, e.g., in determining a threshold voltage distribution of a set of storage elements. In this case, a voltage sweep can be applied to a word line associated with the set of storage elements, and data obtained based on the number of conductive storage elements.

Abstract: A method of storage and retrieval of data in a flash memory system, the flash memory system comprising a cache storage area of relatively high reliability, and a main storage area of relatively low reliability, the method comprising adding to data a level of error correction redundancy higher by a predetermined margin than that required for the cache storage area, writing the data to the cache storage area, and from the cache storage area copying the data directly to the main storage area, the predetermined margin being such as to allow subsequent error correction to compensate for errors accumulated from the cache storage area and the main storage area. In this way the memory die copy back operation can be used for copying the data from the cache to the main memory and two out of four transfers over the data bus to the flash controller are avoided.

Abstract: Information stored as physical states of cells of a memory is read by setting each of one or more references to a respective member of a first set of values and reading the physical states of the cells according to the first set. Then, at least some of the references are set to respective members of a second set of values, and the physical states of the cells are read according to the second set. At least one member of the second set is different from any member of the first set, so that the two readings together read the physical states of the cells with higher resolution than the first reading alone.

Abstract: A method and system for balancing host write operations and cache flushing is disclosed. The method may include steps of determining an available capacity in a cache storage portion of a self-caching storage device, determining a ratio of cache flushing steps to host write commands if the available capacity is below a desired threshold and interleaving cache flushing steps with host write commands to achieve the ratio. The cache flushing steps may be executed by maintaining a storage device busy status after executing a host write command and utilizing this additional time to copy a portion of the data from the cache storage into the main storage. The system may include a cache storage, a main storage and a controller configured to determine and execute a ratio of cache flushing steps to host write commands by executing cache flushing steps while maintaining a busy status after a host write command.

Abstract: A memory device generates one or more read reference voltages rather than being explicitly supplied with each read reference voltage from an external host controller. The technique involves providing a command to the memory device that causes a reading of a set of storage elements by the memory device using a reference voltage which is different than a reference voltage used in a previous reading, where the new read reference value is not explicitly set outside the memory device. In one implementation, the memory device is provided with an initial reference voltage and a step size for generating additional reference voltages. The technique can be used, e.g., in determining a threshold voltage distribution of a set of storage elements. In this case, a voltage sweep can be applied to a word line associated with the set of storage elements, and data obtained based on the number of conductive storage elements.

Abstract: Information stored as physical states of cells of a memory is read by setting each of one or more references to a respective member of a first set of values and reading the physical states of the cells according to the first set. Then, at least some of the references are set to respective members of a second set of values, and the physical states of the cells are read according to the second set. At least one member of the second set is different from any member of the first set, so that the two readings together read the physical states of the cells with higher resolution than the first reading alone.

Abstract: A threshold voltage distribution of a set of storage elements in a memory device is measured by sweeping a control gate voltage while measuring a characteristic of the set of storage elements as a whole. The characteristic indicates how many of the storage elements meet a given condition, such as being in a conductive state. For example, the characteristic may be a combined current, voltage or capacitance of the set which is measured at a common source of the set. The control gate voltage can be generated internally within a memory die. Similarly, the threshold voltage distribution can be determined internally within the memory die. Optionally, storage elements which become conductive can be locked out, such as by changing a bit line voltage, so they no longer contribute to the characteristic. New read reference voltages are determined based on the threshold voltage distribution to reduce errors in future read operations.

Abstract: When a memory device receives two or more pluralities of bits from a host to store in a nonvolatile memory, the device first stores the bits in a volatile memory. Then, in storing the bits in the nonvolatile memory, the device raises the threshold voltages of some cells of the volatile memory to values above a verify voltage. While those threshold voltages remain substantially at those levels, the device raises the threshold voltages of other cells of the volatile memory to values below the verify voltage. In the end, every cell stores one or more bits from each plurality of bits. Preferably, all the cells share a common wordline. A data storage device operates similarly with respect to storing pluralities of bits generated by an application running on the system.

Abstract: Each of a plurality of flash memory cells is programmed to a respective one of L?2 threshold voltage states within a threshold voltage window. A histogram is constructed by determining how many of some or all of the cells have threshold voltages in each of two or more of m?2 threshold voltage intervals within the threshold voltage window. Reference voltages for reading the cells are selected based on estimated values of shape parameters of the histogram. Alternatively, the cells are read relative to reference voltages that define m?2 threshold voltage intervals that span the threshold voltage window, to determine numbers of at least a portion of the cells whose threshold voltages are in each of two or more of the threshold voltage intervals. Respective threshold voltage states are assigned to the cells based on the numbers without re-reading the cells.

Abstract: Information stored as physical states of cells of a memory is read by setting each of one or more references to a respective member of a first set of values and reading the physical states of the cells according to the first set. Then, at least some of the references are set to respective members of a second set of values, and the physical states of the cells are read according to the second set. At least one member of the second set is different from any member of the first set, so that the two readings together read the physical states of the cells with higher resolution than the first reading alone.

Abstract: A flash memory device includes an array of memory cells for storing data pages, at least one buffer (e.g. a memory buffer and a cache buffer) for transferring the data pages to and from the array of memory cells and a host, and an output pin. A logic mechanism is operative to select, from among a plurality of conditions related to an operation on the array of memory cells, a condition that drives a signal being output on the output pin. A data page transfer by the host is contingent on the signal being output on the output pin.

Abstract: Apparatus for producing a three-dimensional model including apparatus for depositing, layer upon layer, a photopolymer material in a selectable configuration and apparatus for curing each photopolymer layer following deposition thereof and prior to deposition thereon of a succeeding layer of photopolymer.