Extent mapping scheme for flash memory devices

Young Kyoon Suh, Bongki Moon, Alon Efrat, Jin Soo Kim, Sang Won Lee

Research output: Chapter in Book/Report/Conference proceedingConference contribution

3 Scopus citations

Abstract

Flash memory devices commonly rely on traditional address mapping schemes such as page mapping, block mapping or a hybrid of the two. Page mapping is more flexible than block mapping or hybrid mapping without being restricted by block boundaries. However, its mapping table tends to grow large quickly as the capacity of flash memory devices does. To overcome this limitation, we propose a novel mapping scheme that is fundamentally different from the existing mapping strategies. We call this new scheme Virtual Extent Trie (VET), as it manages mapping information by treating each I/O request as an extent and by using extents as basic mapping units rather than pages or blocks. By storing extents instead of individual addresses, VET consumes much less memory to store mapping information and still remains as flexible as page mapping. We observed in our experiments that VET reduced memory consumption by up to an order of magnitude in comparison with the traditional mapping schemes for several real world workloads. The VET scheme also scaled well with increasing address spaces by synthetic workloads. With a binary search mechanism, VET limits the mapping time to O(log log|U |), where U denotes the set of all possible logical addresses. Though the asymptotic mapping cost of VET is higher than the O(1) time of a page mapping scheme, the amount of increased overhead was almost negligible or low enough to be hidden by an accompanying I/O operation.

Original languageEnglish (US)
Title of host publicationProceedings of the 2012 IEEE 20th International Symposium on Modeling, Analysis and Simulation of Computer and Telecommunication Systems, MASCOTS 2012
Pages331-338
Number of pages8
DOIs
StatePublished - Nov 6 2012
Event2012 IEEE 20th International Symposium on Modeling, Analysis and Simulation of Computer and Telecommunication Systems, MASCOTS 2012 - Washington, DC, United States
Duration: Aug 7 2012Aug 9 2012

Publication series

NameProceedings of the 2012 IEEE 20th International Symposium on Modeling, Analysis and Simulation of Computer and Telecommunication Systems, MASCOTS 2012

Other

Other2012 IEEE 20th International Symposium on Modeling, Analysis and Simulation of Computer and Telecommunication Systems, MASCOTS 2012
CountryUnited States
CityWashington, DC
Period8/7/128/9/12

Keywords

  • Extent Mapping
  • Flash Memory

ASJC Scopus subject areas

  • Computer Networks and Communications
  • Modeling and Simulation
  • Communication

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  • Cite this

    Suh, Y. K., Moon, B., Efrat, A., Kim, J. S., & Lee, S. W. (2012). Extent mapping scheme for flash memory devices. In Proceedings of the 2012 IEEE 20th International Symposium on Modeling, Analysis and Simulation of Computer and Telecommunication Systems, MASCOTS 2012 (pp. 331-338). [6298193] (Proceedings of the 2012 IEEE 20th International Symposium on Modeling, Analysis and Simulation of Computer and Telecommunication Systems, MASCOTS 2012). https://doi.org/10.1109/MASCOTS.2012.45