Lazy-RTGC: A real-time lazy garbage collection mechanism with jointly optimizing average and worst performance for NAND flash memory storage systems

Qi Zhang, Xuandong Li, Linzhang Wang, Tian Zhang, Yi Wang, Zili Shao

Research output: Journal article publicationJournal articleAcademic researchpeer-review

18 Citations (Scopus)


Due to many attractive and unique properties, NAND flash memory has been widely adopted in mission-critical hard real-time systems and some soft real-time systems. However, the nondeterministic garbage collection operation in NAND flash memory makes it difficult to predict the system response time of each data request. This article presents Lazy-RTGC, a real-time lazy garbage collection mechanism for NAND flash memory storage systems. Lazy-RTGC adopts two design optimization techniques: on-demand page-level address mappings, and partial garbage collection. On-demand page-level address mappings can achieve high performance of address translation and can effectively manage the flash space with the minimum RAM cost. On the other hand, partial garbage collection can provide the guaranteed system response time. By adopting these techniques, Lazy-RTGC jointly optimizes both the average and the worst system response time, and provides a lower bound of reclaimed free space. Lazy-RTGC is implemented in FlashSim and compared with representative real-time NAND flash memory management schemes. Experimental results show that our technique can significantly improve both the average and worst system performance with very low extra flash-space requirements.
Original languageEnglish
Article number43
JournalACM Transactions on Design Automation of Electronic Systems
Issue number3
Publication statusPublished - 1 Jan 2015


  • Garbage collection
  • NAND flash memory
  • Real-time system
  • Storage systems

ASJC Scopus subject areas

  • Computer Science Applications
  • Computer Graphics and Computer-Aided Design
  • Electrical and Electronic Engineering

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