강수용 교수

While NAND flash memory is used in a variety of end-user devices, it has a few disadvantages, such as asymmetric speed of read and write operations, inability to in-place updates, among others. To overcome these problems, various flash-aware strategies have been suggested in terms of buffer cache, file system, FTL, and others. Also, the recent development of next-generation nonvolatile memory types such as MRAM, FeRAM, and PRAM provide higher commercial value to non-volatile RAM (NVRAM). At toda

From file system's point of view, scalable streaming introduces another dimension of complexity in disk scheduling. This is particularly because when a subset of information is retrieved, the playback does not necessarily coincides with the sequential access. We propose a new file organization technique called Harmonic placement. The basic idea is to cluster the frequently accessed layers together. We develop elaborate analytical models for different file organization techniques: Progressive pla

To fully utilize the resources with soft real-time video-on-demand servers, statistical admission control is widely used. There have been several models to capture the nature of bit rate variability of the video data. However, when the video server employs caching, the resulting workload exhibits different characteristics. In this paper, we present a probabilistic model to analyze the video server workload. Our model enables the quantitative analysis of the disk load reduction induced by caching

Since multizone recording disks have different bandwidths and capacities depending on the zone in use, data placement schemes for traditional constant angular density disks are not suitable for multizone recording disks. In this paper, we propose a new block placement algorithm for multizone recording disks used for continuous media servers. The proposed scheme exploits the bandwidth-saving effect of smoothing variable bit rate data before storing them. The diversity of zone bandwidths in multiz