Publications

Characterizing and Emulating FDP SSDs with Warp

Published in 24th USENIX Conference on File and Storage Technologies (FAST '26), 2026

Warp is the first open emulator and comprehensive study of FDP SSDs. It shows FDP sustains near-1 WAF when reclaim-unit-handle isolation aligns with object lifetimes, and reveals how misclassification, RUH interference, or adversarial invalidations break that guarantee — enabling principled, FDP-aware storage system design.

Recommended citation: Inho Song, Shoaib A. Qazi, Javier González, Matias Bjørling, Sam H. Noh, and Huaicheng Li. "Characterizing and Emulating FDP SSDs with Warp." In Proceedings of the 24th USENIX Conference on File and Storage Technologies (FAST '26), Santa Clara, CA, USA, February 2026. https://www.usenix.org/system/files/fast26-song.pdf

CRAZNS: A Case for Conventional Namespace Support for RAID with ZNS SSDs

Published in 40th ACM/SIGAPP Symposium on Applied Computing (SAC '25), 2025

CRAZNS is a ZNS RAID-5 design that uses a small conventional namespace to eliminate dedicated metadata zones and log partial parity with in-place updates. Compared to RAIZN, it saves ~26 GiB of storage, opens more zones, achieves 1.2× higher small-write throughput, and 1.1× higher overall throughput.

Recommended citation: Hangyul Kim, Inho Song, and Sam H. Noh. "CRAZNS: A Case for Conventional Namespace Support for RAID with ZNS SSDs." In Proceedings of the 40th ACM/SIGAPP Symposium on Applied Computing (SAC '25), pp. 1391–1398, Catania, Italy, March 2025. https://doi.org/10.1145/3672608.3707937 https://dl.acm.org/doi/10.1145/3672608.3707937

ConfZNS: A Novel Emulator for Exploring Design Space of ZNS SSDs

Published in 16th ACM International Systems and Storage Conference (SYSTOR '23), 2023

ConfZNS is a configurable ZNS SSD emulator that exposes internal design knobs typically hidden in commercial devices. On average it matches real-device performance within 6–17% error, and reveals design tradeoffs that existing ZNS ecosystems are unaware of.

Recommended citation: Inho Song, Myunghoon Oh, Bryan S. Kim, Seehwan Yoo, Jae-Dong Lee, and Jongmoo Choi. "ConfZNS: A Novel Emulator for Exploring Design Space of ZNS SSDs." In Proceedings of the 16th ACM International Conference on Systems and Storage (SYSTOR '23), pp. 71–82, 2023. https://doi.org/10.1145/3579370.3594772 https://dl.acm.org/doi/10.1145/3579370.3594772

Journal

Overcoming a Zone Reclaiming Overhead with Partial-Zone Reclaiming

Published in Journal of KIISE: Computer Systems and Theory, Vol. 51, No. 2, pp. 115–124, 2024

A partial-zone reclaiming technique that interleaves in-flight host requests with the zone reclaiming process to mitigate reclaim-induced tail latency. Improves host request latency by up to 8% on average and reduces zone reclaiming time by up to 41%.

Recommended citation: Inho Song, Wonjin Lee, Jae-Dong Lee, Seehwan Yoo, and Jongmoo Choi. "Overcoming a Zone Reclaiming Overhead with Partial-Zone Reclaiming." Journal of KIISE: Computer Systems and Theory, vol. 51, no. 2, pp. 115–124, 2024. (Korean) https://dspace.kci.go.kr/handle/kci/2110970

Patents

Method for analyzing vehicle forensic and computing device for execution the same

Published in Korean Patent, 10-2022-0139234 (granted), 2022

Granted Korean patent (10-2022-0139234) covering a method and computing device for vehicle forensic analysis — retrieving critical artifacts from modern in-vehicle storage and reconstructing deleted data through physical dump and metadata analysis.

Recommended citation: Jongmoo Choi, Samuel Woo, and Inho Song. "Method for analyzing vehicle forensic and computing device for execution the same." Republic of Korea, Patent 10-2022-0139234, granted.