Computer ARchitecture &
Embedded Systems Laboratory

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Flash Memory System

AutoBox: Real-Time High-Capacity Flash Storage System for Smart Cars


1. Research Goal 

The goal of this research is to design and implement a real-time high-capacity flash storage system for future self-driving cars, called AutoBox.


- AutoBox outputs a warning signal, ws, which indicates that the I/O throughput of AutoBox has degraded to the minimum acceptable level (which might be custom-configured). In practice, the asserted ws signal indicates that it is time to exchange AutoBox.​






2. Approach : Preemptive NAND Flash with Time-Bounded Read

- In order to make the read latency very tight, we implement the following schemes in AutoBox: 

(1) Support prioritized I/Os in the following order of priority, read > write > erase. This guarantees that a read is always serviced with the top priority.

(2) Modify both a program scheme and an erase scheme to be preemptive in the middle of their operations. We split the long atomic execution of program/erase operations into multiple stages where each stage can be preempted by a higher-priority request. 

(3) When a read is allowed to access the NAND flash, our comprehensive monitor-based read-reference selection scheme chooses the proper read reference value at most two read retries, thus bounding the latency very tightly.​



3. Published papers

- Improving I/O Performance of Large-Page Flash Storage Systems Using Subpage-Parallel Reads

Jisung Park, Myungsuk Kim, Sungjin Lee and Jihong Kim​

- SARO: A State-Aware Reliability Optimization Technique for High Density NAND Flash Memory

Myungsuk Kim, Youngsun Song, Myoungsoo Jung and Jihong Kim​

- Improving Performance and Lifetime of Large-Page NAND Storages Using Erase-Free Subpage Programming

Myungsuk Kim, Jaehoon Lee, Sungjin Lee, Jisung Park, and Jihong Kim


This research is mainly supported by Samsung Research Funding Center for Future Technology.