Journal of KIISE:Computer Systems and Theory (한국정보과학회논문지:시스템및이론)

Korean Institute of Information Scientists and Engineers (한국정보과학회)
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Log Buffer Management Scheme for NAND Flash Memory in Real-Time Systems

실시간 시스템용 낸드 플래시 메모리를 위한 로그 버퍼 관리 기법

  • 조현진 (성균관대학교 컴퓨터공학과) ;
  • 하병민 (성균관대학교 컴퓨터공학과) ;
  • 신동군 (성균관대학교 컴퓨터공학과) ;
  • 엄영익 (성균관대학교 컴퓨터공학과)
  • Published : 2009.12.15
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Abstract

Flash memory is suitable for real time systems because of its consistent performance for random access, low power consumption and shock resistance. However, flash memory needs blocking time to perform a garbage collection to reclaim invalidated pages. Moreover, the worst-case garbage collection time is significantly longer than the best-case garbage collection time. In this paper, we propose a FTL (Flash Translation Layer) mapping scheme called KAST (K-Associative Sector Translation). In the KAST scheme, user can control the maximum association of the log block to limit the worst-case garbage collection time. Performance evaluation using simulation shows that not only KAST completes the garbage collection within the specified time but also provides about 10~15% better average performance than existing FTL schemes.

플래시 메모리는 일관된 성능, 저전력 및 내구성 등의 특징으로 인해 실시간 시스템에 적합한 저장장치로 주목 받고 있다. 하지만 플래시 메모리는 무효화된 페이지의 가비지 컬렉션 수행을 위한 정체 시간(blocking time)을 필요로 하는데, 기존의 플래시 메모리 관리 기법에서는 가비지 컬렉션을 위한 최대 정체 시간(worst case blocking time)과 최소 정체 시간(best case blocking time)의 차가 크다는 문제점이 있다. 본 논문에서는 KAST라 불리는 FTL(Flash Translation Layer)을 제안하며, 제안 시스템에서 사용자는 가비지 컬렉션에 따른 최대 정체 시간을 설정할 수 있도록 한다. 실험을 통해 KAST는 사용자가 설정한 시간 내 가비지 컬렉션을 완료하며, 기존 FTL 보다 10~15% 성능 향상을 보임을 확인한다.

Keywords

References

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