A method, device and medium for improving the success rate of data reading

Abstract

The invention discloses a method, device and medium for improving the success rate of data reading, which are applied in the technical field of solid-state hard disks, read the number of successful samples of the read operation of test sample data under each reference voltage and calculate each success rate, wherein The number of successful samples is the number of error bits of the test sample data with the decoding unit as the unit, which is less than the data of the decoding error correction limit; select the corresponding reference voltage group according to each success rate to generate a fixed look-up table; according to the target reference voltage of the fixed look-up table read data. Select the reference voltage group to generate a fixed look-up table by collecting the success rate of the read operation information of all reference voltages in the reference voltage candidate table at different stages in the Nand flash memory cycle, so as to avoid the deflection of the reference voltage caused by the aging of the chip at the end of the Nand flash memory Thus affecting the problem of failure to read data, improving the success rate of read operations of solid-state drives, improving throughput and hit rate, and ensuring the data storage capacity of solid-state drives.

Description

technical field [0001] The invention relates to the technical field of solid-state hard disks, in particular to a method, device and medium for improving the success rate of data reading. Background technique [0002] Nand flash memory (Nand Flash) is a widely used storage medium at present. Its principle is to record data by presenting different voltage values ​​with different charges stored in the storage unit. However, due to the electrical characteristics of Nand particles, in its life cycle, with the flash memory erase / write times (Program / Erase counts, PE), data retention time (RetentionTime, RT), read times (Read Disturb, RD) and other factors Changes in the memory cell will change the characteristics of the charge stored in the memory cell, so the reference voltage axis will also change accordingly, otherwise the bit error rate (Bit Error Rate, BER) will be too high, exceeding the decoding capability and resulting in read failure. [0003] Under normal circumstances...

AI Technical Summary

Problems solved by technology

However, due to the electrical characteristics of Nand particles, in its life cycle, with the flash memory erase / write times (Program / Erase counts, PE), data retention time (RetentionTime, RT), read times (Read Disturb, RD) and other factors Changes in the memory cell will change the characteristics of the storage charge, so the reference voltage axis will also change accordingly, otherwise it will cause the bit error rate (Bit Error Rate, BER) to be too high, beyond the decoding capability and lead to read failure

[0003] Under normal circumstances, the above situation is generally resolved through Fixed Read Tables (FRT). The generation of the fixed read tables is based on the three dimensions of PE, RT, and RD at different stages of the life cycle of Nand flash memory according to a copy provided by the manufacturer. There are multiple reference voltage candidate tables, and the best three reference voltages are gradually selected from the three dimensions of multiple environmental cycles under each reference voltage, and the fixed reference voltage generated by the reference voltage candidate table is selected in the early stage of the life cycle of Nand flash memory. Table look-up can improve the success rate of reading data, but the life cycle of Nand flash memory is limited, especially at the end of the period, as the chip ages, the data storage capacity of solid-state hard disk will decrease, and the reference voltage will be deflected, which reduces the performance of solid-state hard disk. The success rate of read operations, and the required throughput is also very slow, resulting in a lower hit rate

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