SAFARI Project & Seminars Courses (Fall 2022)

NAND flash memory is the de facto standard for architecting a storage device in modern computing systems. As modern computing systems process a large amount 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 solid-state drive (SSD) can provide orders-of-magnitude higher I/O performance compared to traditional hard-disk drives (HDDs), with a much lower cost-per bit value over 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 cannot reliably store data after experiencing a certain number of program/erase (P/E) cycles), and large operation units (e.g., modern NAND flash memory typically 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, which significantly affect the performance, reliability, and lifetime of the SSD.

In this course, 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. We will also examine other emerging memory technologies for building SSDs, such as Phase Change Memory, 3D XPoint (e.g., Intel Optane SSD) and more.

You will help 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 in modern storage systems and research experience on system optimization with rigorous evaluation.

Prerequisites of the course:

• No prior knowledge in NAND flash-based storage systems is required.
• Digital Design and Computer Architecture (or equivalent course)
• Good knowledge in C/C++ programming language is required.
• Interest in system optimizations

The course is conducted in English.

The course has two main parts: Weekly lectures on modern NAND flash-based SSDs and hands-on projects on storage systems and NAND flash memory.

Course description page Moodle

Recorded Lecture Playlist, Spring 2022

• Arash Tavakkol, Juan Gomez-Luna, Mohammad Sadrosadati, Saugata Ghose, and Onur Mutlu, "MQSim: A Framework for Enabling Realistic Studies of Modern Multi-Queue SSD Devices," In USENIX FAST, 2018.
• MQSim GitHub Repository

• Computer Architecture Fall 2020 - Lecture 26: Flash Memory and Solid-State Drives
• Computer Architecture Fall 2020 - Lecture 14: Simulation (with a Focus on Memory)

• Yu Cai, Saugata Ghose, Erich F. Haratsch, Yixin Luo, and Onur Mutlu, “Errors in Flash-Memory-Based Solid-State Drives: Analysis, Mitigation, and Recovery (Introduction and Section 1),” Invited Book Chapter in Inside Solid State Drives, 2018.
• Jisung Park, Myungsuk Kim, Myoungjun Chun, Lois Orosa, Jihong Kim, and Onur Mutlu, “Reducing Solid-State Drive Read Latency by Optimizing Read-Retry,” In ASPLOS, 2021.

• Arash Tavakkol, Mohammad Sadrosadati, Saugata Ghose, Jeremie Kim, Yixin Luo, Yaohua Wang, Nika Mansouri Ghiasi, Lois Orosa, Juan Gómez Luna, and Onur Mutlu, “FLIN: Enabling Fairness and Enhancing Performance in Modern NVMe Solid State Drives,” In ISCA, 2018.
• Bryan S. Kim, Hyun Suk Yang, and Sang Lyul Min,“AutoSSD: an Autonomic SSD Architecture,” In USENIX ATC, 2018.

• Jisung Park, Roknoddin Azizi, Geraldo F. Oliveira, Mohammad Sadrosadati, Rakesh Nadig, David Novo, Juan Gómez-Luna, Myungsuk Kim, Onur Mutlu, “Flash-Cosmos: In-Flash Bulk Bitwise Operations Using Inherent Computation Capability of NAND Flash Memory,” In MICRO, 2022.

• Aayush Gupta, Yongjae Kim, and Bhuvan Urgaonkar, “DFTL: A Flash Translation Layer Employing Demand-based Selective Caching of Page-level Address Mappings,” In ASPLOS, 2009.

• Jisung Park, Myungsuk Kim, Myoungjun Chun, Lois Orosa, Jihong Kim, and Onur Mutlu, “Reducing Solid-State Drive Read Latency by Optimizing Read-Retry,” In ASPLOS, 2021.
• Guanying Wu and Xunbin He, “Reducing SSD Read Latency via NAND Flash Program and Erase Suspension,” In USENIX FAST, 2012.
• Shine Kim, Jonghyun Bae, Hakbeom Jand, Wenjing Jin, Jeonghun Gong, Seungyeon Lee, Tae Jun Ham, and Jae W. Lee, “Practical Erase Suspension for Modern Low-latency SSDs,” In USENIX ATC, 2019.

• Nika Mansouri Ghiasi, Jisung Park, Harun Mustafa, Jeremie Kim, Ataberk Olgun, Arvid Gollwitzer, Damla Senol Cali, Can Firtina, Haiyu Mao, Nour Almadhoun Alserr, Rachata Ausavarungnirun, Nandita Vijaykumar, Mohammed Alser, Onur Mutlu, “GenStore: A High-Performance and Energy-Efficient In-Storage Computing System for Genome Sequence Analysis,” In ASPLOS, 2022.

• Aayush Gupta, Yongjae Kim, and Bhuvan Urgaonkar, “DFTL: A Flash Translation Layer Employing Demand-based Selective Caching of Page-level Address Mappings,” In ASPLOS, 2009.

• Eran Gal and Sivan Toledo, “Algorithms and data structures for flash memories,” In CSUR, 2005.
• Junghee Lee; Youngjae Kim; Galen M. Shipman; Sarp Oral; Jongman Kim, “Preemptible I/O Scheduling of Garbage Collection for Solid State Drives,” In IEEE TCAD, 2013.
• Sangwook Shane Hahn; Sungjin Lee; Jihong Kim, “To collect or not to collect: Just-in-time garbage collection for high-performance SSDs with long lifetimes,” In DAC, 2015.
• Wonil Choi; Myoungsoo Jung; Mahmut Kandemir; Chita Das, “Parallelizing garbage collection with I/O to improve flash resource utilization,” In HPDC, 2018.
• Fei Wu; Jiaona Zhou; Shunzhuo Wang; Yajuan Du; Chengmo Yang; Changsheng Xie, “FastGC: Accelerate Garbage Collection via an Efficient Copyback-based Data Migration in SSDs,” In DAC, 2018.

• Arash Tavakkol, Juan Gomez-Luna, Mohammad Sadrosadati, Saugata Ghose, and Onur Mutlu, "MQSim: A Framework for Enabling Realistic Studies of Modern Multi-Queue SSD Devices," In FAST, 2018.

• Yu Cai, Saugata Ghose, Erich F. Haratsch, Yixin Luo, and Onur Mutlu, “Errors in Flash-Memory-Based Solid-State Drives: Analysis, Mitigation, and Recovery (Introduction and Section 1),” Invited Book Chapter in Inside Solid State Drives, 2018.
• Jisung Park, Myungsuk Kim, Myoungjun Chun, Lois Orosa, Jihong Kim, and Onur Mutlu, “Reducing Solid-State Drive Read Latency by Optimizing Read-Retry,” In ASPLOS, 2021.
• Myungsuk Kim, Jisung Park, Geonhee Cho, Yoona Kim, Lois Orosa, Onur Mutlu, and Jihong Kim, "Evanesco: Architectural Support for Efficient Data Sanitization in Modern Flash-Based Storage Systems," In ASPLOS, 2020.
• Jisung Park, Jeonggyun Kim, Yeseong Kim, Sungjin Lee, and Onur Mutlu, "DeepSketch: A New Machine Learning-Based Reference Search Technique for Post-Deduplication Delta Compression," In FAST, 2022.

• Arash Tavakkol, Mohammad Sadrosadati, Saugata Ghose, Jeremie Kim, Yixin Luo, Yaohua Wang, Nika Mansouri Ghiasi, Lois Orosa, Juan Gómez Luna, and Onur Mutlu, “FLIN: Enabling Fairness and Enhancing Performance in Modern NVMe Solid State Drives,” In ISCA, 2018.

• Y. Cai, S. Ghose, E.F. Haratsch, Y. Luo, O. Mutlu, "Error Characterization, Mitigation, and Recovery in Flash Memory Based Solid State Drives," Proceedings of the IEEE 2017
• Y. Cai, S. Ghose, Y. Luo, K. Mai, O. Mutlu, E.F. Haratsch, "Vulnerabilities in MLC NAND Flash Memory Programming: Experimental Analysis, Exploits, and Mitigation Techniques," HPCA 2017
• Y. Cai, G. Yalcin, O. Mutlu, E. F. Haratsch, A. Cristal, O. Unsal, and K. Mai, "Flash Correct-and-Refresh: Retention-Aware Error Management for Increased Flash Memory Lifetime," ICCD 2012
• Y. Luo, S. Ghose, Y.Cai, E.F. Haratsch, O. Mutlu, "Enabling Accurate and Practical Online Flash Channel Modeling for Modern MLC NAND Flash Memory", JSAC, 2016
• Y.Cai, Y. Luo, S. Ghose, O. Mutlu, "Read Disturb Errors in MLC NAND Flash Memory: Characterization, Mitigation, and Recovery", DSN, 2015
• Y. Luo, Y.Cai, S. Ghose, J. Choi, O. Mutlu, "WARM: Improving NAND Flash Memory Lifetime with Write-Hotness Aware Retention Management", MSST, 2015
• Y.Cai, Y. Luo, E.F. Haratsch, K. Mai, O. Mutlu, "Data Retention in MLC NAND Flash Memory: Characterization, Optimization, and Recovery", HPCA, 2015
• Y.Cai, Yalcin, Gulay O. Mutlu, E.F. Haratsch, O. Unsal, A. Cristal, K. Mai, "Neighbor-Cell Assisted Error Correction for MLC NAND Flash Memories", SIGMETRICS, 2014
• Y.Cai, O. Mutlu, E.F. Haratsch, K. Mai, "Program Interference in MLC NAND Flash Memory: Characterization, Modeling, and Mitigation", ICCD, 2013
• Y.Cai, Yalcin, Gulay O. Mutlu, E.F. Haratsch, Cristal, Adrian Unsal, Osman S K. Mai, "Error Analysis and Retention-Aware Error Management for NAND Flash Memory", ITJ, 2013
• Y.Cai, E.F. Haratsch, O. Mutlu, K. Mai, "Threshold Voltage Distribution in MLC NAND Flash Memory: Characterization, Analysis, and Modeling", DATE, 2013
• Y.Cai, E.F. Haratsch, O. Mutlu, K. Mai, "Error Patterns in MLC NAND Flash Memory: Measurement, Characterization, and Analysis", DATE, 2012
• B. Schroeder, R. Lagisetty, A. Merchant, "Flash Reliability in Production: The Expected and the Unexpected.", FAST, 2016
• A. Fukami, S. Ghose, Y. Luo, Y.Cai, O. Mutlu, "Improving the Reliability of Chip-Off Forensic Analysis of NAND Flash Memory Devices", Digital Investigation, 2017
• Y. Luo, S. Ghose, Y. Cai, E. F. Haratsch, O. Mutlu, “Improving 3D NAND Flash Memory Lifetime by Tolerating Early Retention Loss and Process Variation," SIGMETRICS, 2018
• Y. Luo, S. Ghose, Y. Cai, E. F. Haratsch, O. Mutlu, "HeatWatch: Improving 3D NAND Flash Memory Device Reliability by Exploiting Self-Recovery and Temperature Awareness," HPCA, 2018
• Y. Cai, S. Ghose, E.F. Haratsch, Y. Luo, O. Mutlu, "Errors in Flash-Memory-Based Solid-State Drives: Analysis, Mitigation, and Recovery," arXiv, 2017
• J. Meza, Q. Wu, S. Kumar, O. Mutlu, "A Large-Scale Study of Flash Memory Failures in the Field," SIGMETRICS, 2015
• Yu Cai, Saugata Ghose, Erich F. Haratsch, Yixin Luo, and Onur Mutlu,"Errors in Flash-Memory-Based Solid-State Drives: Analysis, Mitigation, and Recovery" Invited Book Chapter in Inside Solid State Drives, 2018.
• Yixin Luo, Saugata Ghose, Yu Cai, Erich F. Haratsch, and Onur Mutlu, "Enabling Accurate and Practical Online Flash Channel Modeling for Modern MLC NAND Flash Memory" to appear in IEEE Journal on Selected Areas in Communications (JSAC), 2016.

• HW0 handout