大规模视频点播磁盘cache替换算法

在规划视频播（ＫＳＶＯＤ）中ｃａｃｈｅ机制是提高系统效率的有效手段，是支持ＶＯＤ实用化的关键技术之一，由于连续媒体的数据量大，使用周期长等特点，传统的ｃａｃｈｅ替换算法不能直接应用于ＳＶＯＤ。文中根据ＶＯＤ的特点开发了两种基于访问频率的替换算法，ＬＦＲＵ（ｌｅａｓｔ ｆｒｅｑｕｅｎｃｙ ａｎｄ ｒｅｃｅｎｔｌｙ ｕｓｅｄ）和ＰＬＦＵ（ｐｅｒｉｏｄ ｌｅａｓｔ ｆｒｅｑｕｅｎｃｙ ｕｓｅｄ）算法，它

DISK CACHE REPLACEMENT ALGORITHMS FOR LARGE-SCALE VIDEO-ON-DEMAND SYSTEM

Cache schema is very important for LSVOD (large scale video on demand) system and it is one of the most important techniques to enable VOD to enter market. The disk cache is different from memory cache in several ways for the large volume and high bandwidth requirement of continuous media data. In this paper, two new cache replacement algorithms based on access frequency: LFRU(least frequency and recently used) and PLFU(period least frequency used) are developed. LFRU is a trade off between LRU and LFU, which has advantages of both algorithms. PLFU is an improved LFU algorithm, which solves the cache pollution problem of LFU algorithm. It is shown by means of simulation and experiments that the new algorithms are more effective and more suitable than others for LSVOD system.