M. Kamath, K. Ramamritham, and D. Towsley. Buffer Management for Continuous Media Sharing in Multim edia Database Systems. Technical Report 94-11, University of Massachusetts, Feb. 1994.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....by applying buffer sharing dynamically when a mode transmission occurs. Therefore, the system will not be degraded to a non sharing system which costs more. 4 Related Work There are three main approaches to reduce disk bandwidth requirement in a continuous media server: buffer sharing [DDM 95, KRT94, KRT95b] the idea here is that if one stream for a clip lags another stream for the same clip by only a short time interval, then the system could retain the portion of the clip between the two in buffers. The lagging stream would read from the buffers and not have to read from disk. ....

M. Kamath, K. Ramamritham, and D. Towsley. Buffer Management for Continuous Media Sharing in Multim edia Database Systems. Technical Report 94-11, University of Massachusetts, Feb. 1994.

....the instant a user generates a program request until the time the corresponding program is displayed. Propagation delays across the high speed links are assumed negligible. We adopt batching over alternative techniques for reducing the I O bandwidth requirements of a video server, like bridging [11 13] and adaptive piggybacking [18] because of its simplicity, which makes it easier to introduce it to a video server. We assume a time slotted system, with the slot size equal to the transmission time of an ATM cell (53 bytes) over the shared upstream multiple access channel connecting the users ....

M. Kamath, K. Ramamritham, and D. Towsley, Kamath M, Ramamritham K, Towsley D (1994) Buffer Management for Continuous Media Sharing in Multimedia Database Systems. Technical Report 94-11. University of Massachusetts, Amherst, Mass.

.... (such as video on demand servers) Through buffer and data sharing techniques, such as batching, bridging, and adaptive piggybacking, and prefetching into smart disk caches this research attained a reduction in the required number of SS I O streams required to support video object requests [KRT94,RZ95,GLM96,DS94,Dan95,ASS96,TH99] Thus, so far related research has concentrated on techniques for cleverly exploiting the PS and SS resources of the system in order to increase its performance. With respect to tertiary storage, there have been efforts at modelling the performance ....

M. Kamath, K. Ramamritham, and D. Towsley. Buffer management for continuous media sharing in multimedia database systems. Technical Report 94-11, University of Massachusetts, Amherst, MA, 1994.

....the instant a user generates a program request until the time the corresponding program is displayed. Propagation delays across the high speed links are assumed negligible. We adopt batching over alternative techniques for reducing the I O bandwidth requirements on a video server, like bridging [11], 12] 13] and adaptive piggybacking [18] because of its simplicity which makes it easier to introduce it to a video server. We assume a time slotted system, with the slot size equal to the transmission time of an ATM cell (53 bytes) over the shared upstream multiple access channel connecting ....

M. Kamath, K. Ramamritham, and D. Towsley, "Buffer Management for Continuous Media Sharing in Multimedia Database Systems", Technical Report 94-11, University of Massachusetts, Amherst, 1994. 9

....stream 2 Disks Proc. Nodes display stations (a) batching Figure 2: Data Sharing In this paper we concentrate on adaptive piggybacking. It is a more innovative approach and, to the best of our knowledge, has not been studied (or even proposed) before. Some work on batching [5] and bridging [8] does exist. An adaptive piggybacking procedure is defined to be a policy for altering display rates of requests in progress (for the same object) for the purpose of merging their respective I O streams into a single stream, which can serve the entire group (of merged requests) The idea is ....

M. Kamath, D. Towsley, and K Ramamritham. Buffer Management for Continuous Media Sharing in Multimedia Database Systems. Technical Report 94-11, University of Massachusetts, February 1994.

....large body of research in the area of storage servers. One thread of this research concentrates on developing techniques to reduce the number of secondary storage I Os by exploiting the characteristics of several emerging applications (such as video on demand servers) and main memory buffer caches [13, 23, 11, 7]. Another thread focuses on the secondary storage medium. This research led to the construction of disk arrays [22] and to the development of new methods for placing data objects on disk arrays, which attempt to exploit their potential for high performance and reliability [24, 22, 12, 8] A key ....

M. Kamath, K. Ramamritham, and D. Towsley, "Buffer Management for Continuous Media Sharing in Multimedia Database Systems", Technical Report 94-11, University of Massachusetts, Amherst, 1994.

....the use of a buffer space so that at any moment of time a contiguous length of the video is being buffered. Thus, a pair of requests which are less than this length apart can be serviced using an appropriately scheduled buffered stream. More details on the technique of bridging may be found in [9] and [21] The technique of bridging has the potential disadvantage that a considerable amount of buffer space may be required in order to achieve substantial savings in server capacity. Recently, a technique called adaptive piggybacking was proposed [8] In this algorithm, the display rates are ....

Kamath, M., Towsley D., and Ramamritham, K., "Buffer Management for Continuous Media Sharing in Multi-media Database Systems," Technical Report 94-11, University of Massachusetts, February 1994.

....(for the same object) until their corresponding I O streams can be merged into one In this paper we concentrate on adaptive piggybacking. It is a more innovative approach and, to the best of our knowledge, has not been studied (or even proposed) before. Some work on batching [4] and bridging [9] does exist. An adaptive piggybacking procedure is defined to be a policy for altering display rates of requests in progress (for the 3 We will not consider the characteristics of the tertiary device in this paper. 4 For instance, a movie server would have such characteristics, where a small ....

M. Kamath, D. Towsley, and K Ramamritham. Buffer Management for Continuous Media Sharing in Multimedia Database Systems. Technical Report 94-11, University of Massachusetts, February 1994.

....be used to service another) can be categorized as follows: 1. batching [5, 4, 13, 20] i.e. delaying requests for up to T i time periods in hopes of more requests, for the same object i, arriving during the batching interval and servicing the entire group using a single I O stream, 2. buffering [11, 10, 3], i.e. closing the temporal gaps between successive requests through the use of buffer space, i.e. holding data read for a leading stream and servicing trailing requests out of the buffer rather than by issuing another I O stream, and 3. adaptive piggybacking [8, 7, 12, 1] i.e. adjusting ....

M. Kamath, K. Ramamritham, and D. Towsley. Buffer Management for Continuous Media Sharing in Multimedia Database Systems. Technical Report 94-11, University of Massachusetts, Feb. 1994.

....exceeds p and the application can tolerate p time intervals latency time. The maximum latency observed by a user before the display of the DAG starts is intervals: Max(p; Max Display Gamma R p) 13) where the unit of Max Display is in number of time intervals rather than seconds. In [KRT94], it is sug15 u x w z y SIZE(x) 6 subobjects SIZE( y) 5 subobjects SIZE(z) 6 subobjects SIZE(w) 4 subobjects SIZE(u) 3 subobjects Figure 9: A sample DAG for Data Driven Paradigm xyzwu xzwu xyu xwu xzu xyzu xyzwu xzwu xyu xwu xzu xyzu i5 i4 i3 i2 i1 i6 i5 i4 i3 i2 i1 i6 a. The First ....

M. Kamath, K. Ramamritham, and D. Towsley. Buffer Management for Continuous Media Sharing in Multimedia Database Systems. In Proceedings of the International Conference on Very Large Databases, 1994.

....segment of a particular video is being buffered as it plays for a particular viewer. Then a viewer who is trailing the original viewer by an amount less than this segment can be serviced from this buffered stream instead of from disk. More details on the technique of bridging may be found in [19, 29]. The key issue is to determine which segments of which instances of video streams should be buffered. One can actually derive an optimal bridging algorithm as a greedy solution to an extremely simple optimization problem, but we shall omit this in the current paper. Recently, a third technique ....

Kamath, M., Towsley D., and Ramamritham, K., "Buffer Management for Continuous Media Sharing in Multi-Media Database Systems,"

....perform close to optimum in the presence of multiple video on demand workloads. The technique of bridging where, in the presence of multiple requests for the same video, buffers are used to hold data read for a leading stream so that I O can be avoided for the trailing stream is presented in [22]. The SPIFFI CHAPTER 3. RELATED WORK 27 system [13] implements a state based buffer scheme called love prefetch replacement. It has two states, prefetched and referenced, with buffers from the referenced state being assigned a lower priority. Thus, it is similar but simpler than the MMFS ....

Kamath, M., Towsley, D., and Ramamritham, K. Buffer management for continuous media sharing in multimedia database systems. Technical Report 94-11, University of Massachusetts, February 1994.

....performance of the proposed schemes. We show in Section 4 that the proposed schemes can outperform substantially FCFS and MQL in reducing the turn away probability. A summary is given in Section 5. We briefly comment on some related works that study alternative means to support stream sharing. In [4, 7], a bridging approach that uses buffering to support stream sharing is considered. By keeping the last few minutes of a leading video request in buffer, trailing requests can be served out from the buffer. In [9] buffers are used to support pause resume under batching in a lookahead scheduling ....

M. Kamath, D. Towsley and K. Ramamritham, "Buffer Management for Continuous Media Sharing in Multimedia Database Systems", Technical Report 94-11, Univ. of Massachusetts, Feb. 1994.

....or the CPU of the video server. The disadvantage of this method is that when stream rates vary as a function of time, video server bandwidth is wasted. To ameliorate this situation, the second technique employed has been to adapt the bandwidth allocation to the stream s dynamic rate requirements [2, 7, 18]. The bandwidth requirement of a stored video stream, known a priori, is used to construct a bandwidth allocation schedule. We call this the planned bandwidth allocation method. This allows resource reservation at a finer granularity than the peak allocation method, potentially admitting more ....

KAMATH, M., RAMAMRITHAM, K., AND TOWSLEY, D. Buffer Management for Continuous Media Sharing in Multimedia Database Systems. Tech. Rep. 94-11, Department of Computer Science, University of Massachusetts, Amherst, MA 01003, 1994.

No context found.

M. Kamath, K. Ramamritham and D. Towsley, "Buffer Management for Continuous Media Sharing in Multimedia Database Systems", Technical Report 94-11, Department of Computer Science, University of Massachusetts, February 1994.

....scheme BAT UAT, created BAT SHR, a new scheme that compounds the effect of sharing. We have also done a preliminary analysis of our schemes to determine the enhancements necessary to support fast forward and rewind but have not included it here to keep the discussion short (details can be found in [15]) We studied the impact of continuous media sharing by measuring the disk bandwidth required for 95 of the requests to succeed. We observed that the disk bandwidth required for SHR is low in all cases. This verifies the fact that SHR reduces the number of disk I Os by promoting sharing and can ....

M. Kamath, K. Ramamritham and D. Towsley, "Buffer Management for Continuous Media Sharing in Multimedia Database Systems", Technical Report 94-11, Department of Computer Science, University of Massachusetts, February 1994.

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