Analysis on applicable error-correcting code strength of storage class memory and NAND flash in hybrid storage
Analysis on applicable error-correcting code strength of storage class memory and NAND flash in hybrid storage
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存储类存储器与NAND闪存在混合存储中适用的纠错码强度分析
DOI：
10.7567/jjap.57.04fe01
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发表时间：
2018
影响因子：
1.5
通讯作者：
K. Takeuchi
中科院分区：
文献类型：
--
作者：
C. Matsui;Reika Kinoshita;K. Takeuchi
存储级存储器（SCM）和NAND闪存的混合是一种很有前途的高性能存储技术。由于误码率（BER）随着写/擦除（W/E）周期、数据保留和程序/读干扰的增加而增加，因此在单片机和NAND闪存上纠错是不可避免的。此外，缩放和多级小区技术增加了误码率。然而，由于额外的内存读取和编码/解码时间，纠错码（ECC）降低了存储性能。因此，通过在混合存储中固定一个存储器的ECC强度，可以独立评估SCM和NAND闪存的适用ECC强度。因此，由于单片机访问频率高，对于大容量的混合存储，推荐采用可纠错位小的弱BCH ECC。相比之下，强且长延迟的LDPC ECC可以应用于大容量SCM混合存储中的NAND闪存，因为大容量SCM提高了存储性能。
A hybrid of storage class memory (SCM) and NAND flash is a promising technology for high performance storage. Error correction is inevitable on SCM and NAND flash because their bit error rate (BER) increases with write/erase (W/E) cycles, data retention, and program/read disturb. In addition, scaling and multi-level cell technologies increase BER. However, error-correcting code (ECC) degrades storage performance because of extra memory reading and encoding/decoding time. Therefore, applicable ECC strength of SCM and NAND flash is evaluated independently by fixing ECC strength of one memory in the hybrid storage. As a result, weak BCH ECC with small correctable bit is recommended for the hybrid storage with large SCM capacity because SCM is accessed frequently. In contrast, strong and long-latency LDPC ECC can be applied to NAND flash in the hybrid storage with large SCM capacity because large-capacity SCM improves the storage performance.