CATA: A Garbage Collection Scheme for Flash Memory File Systems
The problem of flash memory is that it cannot be overwritten unless erased in advance. In order to avoid having to erase during every update, non-in-place-update schemes have been widely used. In case of non-in-place update mechanism, garbage collection is needed to reclaim the obsolete space. In this paper, we study a new garbage collection scheme to reduce its cost such as the number of erase operations and the number of data copies. The proposed scheme determines the victim blocks by exploiting usage information of data blocks such as age, utilization and erase count. In addition, the proposed scheme predicts the future I/O workload and controls the number of victims to avoid disturbing the normal I/O operations. Experimental results show that the proposed scheme can perform well especially when the degree of locality is high.
KeywordsGarbage Collection Migration Cost Garbage Collector NAND Flash Request Arrival
Unable to display preview. Download preview PDF.
- 1.Yaffs (yet another flash filing system), http://www.aleph1.co.uk/yaffs/
- 2.Box, G., Jenkins, G.: Time Series Analysis: Forecasting and Control. Holden-Day (1976)Google Scholar
- 3.Chandra, A., Gong, W., Shenoy, P.: Dynamic resource allocation for shared data centers using online measurements (2002)Google Scholar
- 7.Douglis, F., Caceres, R., Kaashoek, F., Li, K., Marsh, B., Tauber, J.: Storage alternatives for mobile computers. In: Proceedings of the 1st Symposium on Operating Systems Design and Implementation (1994)Google Scholar
- 8.Samsung Electronics. 256m x 8bit / 128m x 16bit nand flash memory, http://www.samsungelectronics.com
- 9.Kawaguchi, A., Nishioka, S., Motoda, H.: Flash memory based file system. In: Proceedings of USENIX 1995, pp. 155–164 (1995)Google Scholar
- 10.Kim, H., Lee, S.: An effective flash memory manager for reliable flash memory space management. IEICE Trans. Information and Systems E85-D(6), 950–964 (2002)Google Scholar
- 11.Marsh, B., Douglis, F., Krishnan, P.: Flash memory file caching for mobile computers. In: Proceedings of the 27th Hawaii International Conference on Systems Sciences (1994)Google Scholar
- 14.Woodhouse, D.: Jffs: The journalling flash file system. In: Proceedings of the Ottawa Linux Symposium (2001)Google Scholar
- 15.Wu, M., Zwanepoel, W.: envy: A non-volatile, main memory storage system. In: Proceedings of the 6th Internation Conference on Architectural Support for Programming Languages and Operating Systems (1994)Google Scholar