A method of testing a three dimensional (3D) memory cell array includes writing data to each layer of memory cells in the 3D memory cell array, simultaneously performing a read operation of each memory cell in at least a first pillar of the 3D memory cell array, determining whether a memory cell in the 3D memory cell array has failed in response to the read operation, and replacing at least one failed memory cell in the 3D memory cell array with a spare memory cell in response to determining that the memory cell in the 3D memory cell array has failed. The first pillar includes memory cells on each corresponding layer of the 3D memory cell array.

System, method and computer program product for prioritizing trial-and-error attempted corrections of bit/s, in a memory, in which logical bit levels are determined by thresholding voltage values using threshold/s, the method comprising ranking bits such that a first bit is ranked before a second bit, which is less likely than said first bit to be erroneous and sequentially attempting to correct the bits in order of the ranking, including attempting to correct the first bit before attempting to correct the second bit.

System, method and computer program product for prioritizing trial-and-error attempted corrections of bit/s, in a memory, in which logical bit levels are determined by thresholding voltage values using threshold/s, the method comprising ranking bits such that a first bit is ranked before a second bit, which is less likely than said first bit to be erroneous and sequentially attempting to correct the bits in order of the ranking, including attempting to correct the first bit before attempting to correct the second bit.

Various examples described herein are directed to systems and methods for generating data values using a NAND flash array. A memory controller may read a number of memory cells at the NAND flash array using an initial read level to generate a first raw string. The memory controller may determine that a difference between a number of bits from the first raw string having a value of logical zero and a number of bits from the first raw string having a value of logical one is greater than a threshold value and read the number of memory cells using a second read level to generate a second raw string. The memory controller may determine that a difference between a number of bits from the second raw string having a value of logical zero and a number of bits from the second raw string having a value of logical one is not greater than a threshold value and applying a cryptographic function using the second raw string to generate a first PUF value.

An electronic device includes a pattern data generation circuit and a data input/output (I/O) circuit. The pattern data generation circuit generates pattern data having a serial pattern based on a command/address signal. The data I/O circuit outputs the pattern data or read data as internal data based on a read command for a read operation and an internal command in a test mode. The data I/O circuit receives and stores the internal data, which are output, as write data for a write operation.

An electronic device includes a pattern data generation circuit and a data input/output (I/O) circuit. The pattern data generation circuit generates pattern data having a serial pattern based on a command/address signal. The data I/O circuit outputs the pattern data or read data as internal data based on a read command for a read operation and an internal command in a test mode. The data I/O circuit receives and stores the internal data, which are output, as write data for a write operation.

In a method of generating a signal for test in a memory device configured to output a multi-level signal, an operation mode is set to a first test mode. During the first test mode, first data bits included in a plurality of test data are arranged based on a first scheme. Each of the plurality of test data includes two or more data bits. During the first test mode, a first test result signal having two voltage levels is generated based on the first data bits according to the first scheme. The operation mode is set to a second test mode during which second data bits included in the plurality of test data are arranged based on a second scheme. During the second test mode, a second test result signal having the two voltage levels is generated based on the second data bits according to the second scheme.

A memory system includes a memory device including memory cells, and a controller that performs a write operation, a read operation, and a check operation on the memory device. During the check operation, the controller controls the memory device to read check data from target memory cells of the memory cells by using a check level, compares the check data with original data stored in the target memory cells, and determines a reliability of the target memory cells or the check data based on a result of the comparison.

A memory system includes a memory device including memory cells, and a controller that performs a write operation, a read operation, and a check operation on the memory device. During the check operation, the controller controls the memory device to read check data from target memory cells of the memory cells by using a check level, compares the check data with original data stored in the target memory cells, and determines a reliability of the target memory cells or the check data based on a result of the comparison.

A memory device to generate intelligent, proactive responses to a read command. For example, signal and noise characteristics of a group of memory cells in a memory device are measured to determine a read voltage. An action is identified based on evaluation of the quality of data retrievable using the read voltage from the group of memory cells. While a response indicating the action is provided responsive to the command, the memory device can initiate the action proactively before a subsequent command, following the response, is received.