Abstract
Highly reliable and low power solid-state drive (SSD)
is proposed. Through the analysis based on measured error rate in
the SSDs with NAND flash memories, the memory cell error shows
the asymmetric characteristic in multilevel cell (MLC) NAND flash
memories. The proposed asymmetric coding increases the number
of “1” s or “0” s of the programming data to reduce the data re-
tention error. The numbers o f the memory cells in the higher
states are reduced. The memory cell error is reduced by 90% with