13189402

Paragraph Number

239

For example, for NAND flash solid-state storage, the write voltage and/or other program related configuration parameters, changes the state of a storage cell from a binary one to a binary zero. The write voltage module 416, in one embodiment, writes known patterns to the storage cells, then reads the pattern back determining the read voltage threshold, and adjusts the write threshold until the desired read threshold is met. The write voltage module 416, in a further embodiment, adjusts the write voltage level based on a mathematical model that specifies write voltage level values based on endurance and data retention requirements of a storage cell relative to an age of the storage cell. In one embodiment, the age of the storage cell is computed in terms of program and erase cycles. The write voltage module 416, in one embodiment, performs a test write to one or more storage cells, detects the read voltage of at least one of the storage cells, and adjusts the write voltage level until the read voltage meets a threshold value. The write voltage module 416, in a further embodiment, performs the test write by writing a data set with a known bias to the storage cells, and tests the read voltage by determining if a read bias of the read data set deviates from the known bias.

Added by DJM 3 2021