NAND flash memory is the de facto standard in architecting a storage device in modern computing systems. As modern computing systems process large amounts of data at an unprecedented scale, a storage device needs to meet high requirements on storage capacity and I/O performance. A NAND flash-based SSD can provide an order(s) of magnitude higher I/O performance compared to traditional hard-disk drives (HDDs), with a much lower cost-per-bit value over any other SSDs based on emerging non-volatile memory (NVM) technologies.
NAND flash memory has several unique characteristics, such as the erase-before write property (i.e., a flash cell needs to be first erased before programming it), limited lifetime (i.e., a cell can reliably store data for a certain number of program/erase cycles), and large operation units (e.g., a NAND flash chip reads/writes data in a page (e.g., 16 KiB) granularity). To achieve high performance and large capacity of the storage system while hiding the unique characteristics of NAND flash memory, it is critical to design efficient SSD firmware, commonly called Flash-Translation Layer (FTL). An FTL is responsible for many critical management tasks, such as address translation, garbage collection, wear-leveling, and I/O scheduling, that significantly affect the performance, reliability, and lifetime of the SSD.
In this P&S, we will cover how a modern NAND flash-based SSD is organized and operates, from the basics of underlying NAND flash devices and various SSD-management tasks at the FTL level. You will build a practical SSD simulator by refactoring MQSim, a state-of-the-art simulator for high-end SSDs, to support advanced features of modern NAND flash chips and essential SSD-management tasks. This will allow you to have the chance to obtain a comprehensive background of modern storage systems and research experience on system optimization with rigorous evaluation.
Prerequisites of the course:
The course is conducted in English.