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讨论了视频服务器中变比特率（ＶＢＲ）视频流的Ｉ／Ｏ调度问题．其中重点讨论了Ｉ／Ｏ调度中的接纳控制算法．首先提出了Ｂｉ－ＳＣＡＮ磁盘调度算法，并将其应用到ＶＢＲ视频流的Ｉ／Ｏ调度．接着讨论了两种确定性接纳控制算法．确定性接纳控制能提供确保的服务质量，但系统资源的利用率很低．为此提出了一种基于统计复用的统计接纳控制算法，该算法将ＶＢＲ视频数据复杂的统计特性转化为磁盘提交的数据块数量的统计特性，使问题得到简化．算法计算量小、容易实现，其计算结果与仿真实验结果非常接近．结果表明，使用统计复用方法，可在系统超载概率为１０~(－６)的情况下，使并发用户数提高数倍。
Discussed I / O scheduling problems for video bitstreams with variable bit rate (VBR) video streaming. Which focuses on the I / O scheduling admission control algorithm. First proposed Bi-SCAN disk scheduling algorithm, and its application to VBR video stream I / O scheduling. Then two deterministic admission control algorithms are discussed. Deterministic admission control can provide assured quality of service, but system resource utilization is low. Therefore, a statistical admission control algorithm based on statistical multiplexing is proposed, which transforms the complex statistical characteristics of VBR video data into the statistical characteristics of the number of data blocks submitted by disk, which simplifies the problem. The algorithm has a small amount of calculation and is easy to implement. The calculation results are very close to the simulation results. The results show that the statistical multiplexing method can increase the number of concurrent users several times when the system overload probability is 10 ~ (-6).