D. P. Anderson, Y. Osawa, R. Govindan. Real-Time Disk Storage and Retrieval of Digital Audio/Video Data. TR UCB/CSB 91/646, University of California, Berkely, September 1991.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....log, the bulky continuous media data can be efficiently read from and written to disk. However, building such a combined service on a LFS is still a major task: all of the other UNIX file system problems still need to be solved. 2. 2 Anderson s Continuous Media File System Anderson et al. [2] describe a file system for continuous media that makes use of sessions. Each client opens a session with the continuous media server and when the server accepts the session, the client is guaranteed a minimal performance from the server. Each session contains a FIFO that acts as an intermediary ....

....deal with variable bit rate transfers. The other two policies distribute slack time to streams that need extra bandwidth. Anderson et al. do not use an EDF scheduler because Policies for real time CPU scheduling, such as earliest deadline first, are not immediately relevant because of seeks ([2], p. 325) Itis true that it is not efficient to preempt a disk transfer if a higher priority request arrives (if such an operation can be performed at all) but this can be solved by not allowing disk preemption and using EDF only as a disk queue ordering policy. 14 Anderson et al. do not try ....

[Article contains additional citation context not shown here]

David P. Anderson, Yoshitomo Osawa, and Ramesh Govindan. The Continuous Media File System (Real-Time Disk Storage and Retrieval of Digital Audio/Video Data). USENIX Conference Proceedings (San Antonio, TX), pages 157--64. USENIX, Summer 1992.

....but rarely implemented. Four example domains include: 1. Multimedia: with the explosion of the Internet, Web content developers would like a le system that can store HTML, image, and audio les more eciently so they can be retrieved faster with HTTP servers, or be played back in real time [Anderson92, Ramakrishnan93, Fall94, Mercer94, Pasquale94]. 2. Databases: researchers are looking for methods to improve the performance of Unix le systems, and or for le systems that provide built in support for concurrency [Stonebraker81, Stonebraker86] 3. Mobility: replicated and distributed le systems with disconnected and caching operations ....

D. P. Anderson, Y. Osawa, and R. Govindan. The Continuous Media File System (RealTime Disk Storage and Retrieval of Digital Audio/Video Data). USENIX Conference Proceedings (San Antonio, TX), pages 157-64. USENIX, Summer 1992.

....originally a Japanese word. It is a popular entertainment in Asian countries, where people sing along with words shown on a music video on TV. 2 policies are discussed in Pitsillides and Lambert [7] and Haas [8] On the server side, multimedia servers have been considered by Anderson, et al. [9, 10], Gemmell and Christodoulakis [11] Little and Ghafoor [12] etc. In short, most of the work done has been focused on two types of systems. One type is systems for large scale video on demand applications [1, 2, 3] These systems can serve thousands of users through the use of high end dedicated ....

D. Anderson, Y. Osawa, R. Govindan. "Real-time Disk Storage and Retrieval of Digital Audio and Video". Technical Report No. UCB/CSD 91/646, Computer Science Division, University of California, Berkeley, California 94720, August 8, 1991.

....under light CPU workloads. However, during CPU overload conditions, RTFS can become unstable because the disk management activities are not properly scheduled by the kernel. The co scheduling problem between the processor and the disk is discussed in the continuous media file system (CMFS) in [8]. CMFS is designed and implemented to support real time storage and retrieval of continuous media data. It uses a buffering technique to reduce the level of synchronization between the application and the disk server. The response time of disk accesses is improved by a disk layout adjustment in ....

D. P. Anderson, Y. Osawa and R. Govindan. Real-Time Disk Storage and Retrieval of Digital Audio/Video Data. Technical Report No. UCB/CSD 91/646. Computer Science Division (EECS), University of California Berkeley. August 8, 1991.

....CPU workloads. However, during CPU overload situation, RTFS can become unstable because the disk management activities are not properly scheduled by the kernel. More consideration of the co scheduling between the processor and the disk is mentioned in the continuous media file system (CMFS) in [8]. CMFS is designed and implemented to support real time storage and retrieval of continuous media data. It uses a buffering technique to reduce the level of synchronization between the application and the disk server. The response time of disk accesses is improved by a disk layout adjustment in ....

D. P. Anderson, Y. Osawa and R. Govindan. Real-Time Disk Storage and Retrieval of Digital Audio/Video Data. Technical Report No. UCB/CSD 91/646. Computer Science Division (EECS), University of California Berkeley. August 8, 1991.

....consumer may experience glitches in the delivery of the movie. To ensure glitch free service, the video server has to guarantee finishing the three components of the service in a fixed amount of time. Guaranteeing delay bounds in service component (1) is addressed by appropriate disk scheduling [2, 1, 3, 4]. The problem of ensuring delay bounds in service component (2) is addressed in this paper. When multiple transmissions take place simultaneously over the network, the delays experienced by individual transmissions depend on the contention experieinced in the network. Worst case assumptions of ....

....links and this contention varies based on the network load. Also, a network transfer requires multiple resources (links, input and output ports) unlike the assumption of requiring only one resource in these studies. Hence, these results cannot be directly applied to our problem. Recent work [2, 1, 3, 4, 8] has looked at disk scheduling in a video server. File systems for handling continuous media have been proposed [9, 10, 11, 12, 13] Multicomputer based video servers are studied in [14, 15, 16] Related work in multicomputer communication includes estimation of delays in the network [17, 18, 19] ....

D. P. Anderson, Y. Osawa, and R. Govindan. Real-time disk storage and retrieval of digital audio/video data. Tech. report UCB/CSD 91/646, Univ. of Cal., Berkeley, Aug. 1991.

....implementation. Recognizing the need for simpler policies and the fact that data may be placed to bound seek delays, several deterministic models have been proposed to study periodic policies and associated data placement. With periodic policies, data streams are accessed in a periodic order. In [11], Anderson et al. proposed an iterative algorithm for calculating the minimumperiod and approximate buffer requirement for accessing multiple fixed rate streams on a block by block basis. Simulation results on the buffer requirements for certain classes of open loop and closed loop periodic ....

....the buffer and reschedule without introducing loss. Buffer Size (MB) 10 0.1 #of Files = 1.4Mbps) i 8 10 0.1 Buffer Size (MB) #of Files 1.4Mbps) CDC WrenIII,R=8.6Mbps, 35ms CDC WrenV,R=11.8Mbps, 39ms d Sony Optical 5.25in,R=5. 2Mbps, 180ms a) from analysis b) from simulation of [11] Figure 12: Validation of Minimum Buffer Required for Periodic Policies 5.3 Remarks The main advantage of the open loop policy of x 5.1 is its quick convergence, but its limit cycle location is dependent on the initial state, and requires explicit and precise knowledge of the SAS parameters in ....

[Article contains additional citation context not shown here]

D. P. Anderson, Y. Osawa, and R. Govindan, "Real-Time Disk Storage and Retrieval of Digital Audio/Video Data," tech. rep., U.C. Berkeley, EECS Dept., Report No. UCB/CSD 91/646, August 1991.

....data types whose bandwidth requirement ( D ) 1 remains fixed as a function of time for the entire display time of a clip. To guarantee a hiccup free display, a clip must be produced at a rate of D . This is accomplished using the concept of time period ( E ) and logical blocks ( F ) [29, 24, 1]. Both, data placement and retrieval are performed in a round robin manner. Once a request arrives referencing object G , the system produces a logical block of G per time period starting with GIH . The display time of a block is equivalent to the duration of a time period. A client ....

D. Anderson, Y. Osawa, and R. Govindan. Real-time disk storage and retrieval of digital audio and video. UCB/ERL Technical Report M91/646, UC Berkeley, 1991.

....will be described in detail in Chapter 5. Rate based flow control is provided by the server. Clients may vary the speed of any continuous media stream during playback. No acceptance control is implemented. 2. 7 UCB Continuous Media File Server The Continuous Media File Server CMFS outlined in [Anderson91] is designed to support real time and non real time access to files. Simulation results supply a comparison of different design choices with a variety of hardware assumptions. The actual implementation of the CMFS provides only a subset of the following design issues needed to provide data rate ....

....2.4. Client requests for data to independent servers are synchronised by the client. A server based flow control mechanism using node striping would require a potentially complicated inter server synchronisation scheme to maintain stream synchronisation. The method used for flow control in [Anderson91], although it is not explicitly stated, is a hybrid between the client and server based approaches. Essentially, a client will request a continuous media stream at a data rate R and the server will begin to buffer the stream according to that rate. The client is then expected to read the stream ....

D. P. Anderson, Yoshitomo Osawa, and Ramesh Govindan. Real-Time Disk Storage and Retrieval of Digital Audio /Video data. Technical Report, Computer Science Division. University of California, Berkeley, August 1991. (pp 15, 32)

....is a single system, where different choices of parameters support different application requirements. Several related studies have described the implementation of continuous media servers 1 . These can be categorized into single disk and multi disk systems. The single disk systems include [AOG92, LS92, RC95, GBC94] These pioneering studies were instrumental in identifying the requirements of continuous 1 We do not report on commercial systems due to lack of their implementation detail, see [Nat95] for an overview of these systems. 2 media. They developed scheduling policies for ....

D. P. Anderson, Y. Osawa, and R. Govindan. Real-Time Disk Storage and Retrieval of Digital Audio /Video Data. IEEE Transactions on Computer Systems, 1992.

....media data types whose bandwidth requirement (RC ) 1 remains fixed as a function of time for the entire display time of a clip. To guarantee a hiccup free display, a clip must be produced at a rate of RC . This is accomplished using the concept of time period (Tp ) and logical blocks (B l ) [29, 24, 1]. Both, data placement and retrieval are performed in a round robin manner. Once a request arrives referencing object X , the system produces a logical block of X per time period starting with X0 . The display time of a block is equivalent to the duration of a time period. A client initiates the ....

D. Anderson, Y. Osawa, and R. Govindan. Real-time disk storage and retrieval of digital audio and video. UCB/ERL Technical Report M91/646, UC Berkeley, 1991.

....processes. However, they do not directly address I O related issues, which are important in the multimedia context. MMFS could potentially be integrated with a real time process scheduler. Support for synchronization at the user level is provided in the Tactus toolkit [4] and the Acme I O server [2]. In contrast to these proposals, the MMFS approach lends itself to potential low level optimizations. A scheme similar to the MMFS approach for editing support is suggested, but not implemented, in the Audition audio system implemented on DOS [5] There are several shortcomings with the Audition ....

Anderson, D. P., Osawa, Y., and Govindan, R. Realtime disk storage and retrieval of digital audio/video data. Technical Report UCB/CSD 91/646, Dept of EECS, University of California at Berkeley, August 1991.

....Instead, there is a single system, where different choices of parameters support different applications. Several related studies have described the implementation of continuous media servers 1 . These can be categorized into single disk and multi disk systems. The single disk systems include [AOG92, LS92, RC95, GBC94] These pioneering studies were instrumental in identifying the requirements of continuous media. They developed scheduling policies for retrieving blocks from disk into memory to support a continuous display. Mitra employs these policies as detailed in Section 3. Compared ....

D. P. Anderson, Y. Osawa, and R. Govindan. Real-Time Disk Storage and Retrieval of Digital Audio /Video Data. IEEE Transactions on Computer Systems, 1992.

....an active research topic [1, 2, 3, 4, 5, 6, 7] One of the most This research was sponsored in part by the National Science Council of R.O.C. under grant NSC 83 0408 E 002 002. important applications of multimedia storage systems is on demand playback of video or high quality audio programs [5, 6, 8, 9, 10, 11, 12, 13, 14]. In on demand playback applications, the storage system supports concurrent retrieval of continuous video or audio programs requested by a large number of clients. Such applications impose two major challenges to mass storage system design: 1. High data retrieval bandwidth The data retrieval ....

D. Anderson, Y. Osawa, and R. Govindan. Realtime disk storage and retrieval of digital audio and video. Technical report, U.C. Berkeley, September 1991. UCB Technical Report.

....sequence is changed, it is necessary that the following data block be delivered to the customer within a very short time to preserve the feel of interactivity. In this paper, we address this problem of achieving short, specifically sub second, response times for these requests. Recent work [3, 1, 4, 5, 6] has looked at disk scheduling in a video server. File systems for handling continuous media have been proposed [7, 8, 9, 10] Pause resume and reverse forward type interactivity is addressed in some of the recent work [11, 12, 13] Most of this work on interactivity is concerned about the impact ....

D. P. Anderson, Y. Osawa, and R. Govindan. Real-time disk storage and retrieval of digital audio/video data. Tech. report UCB/CSD 91/646, Univ. of Cal., Berkeley, Aug. 1991.

....assigns the minimum value to each k i , i.e. k 1 = k 2 = Delta Delta Delta = k r = 1, and then selectively increments the values of each k i until the continuous retrieval equation (Equation (2) is satisfied. The values of k 1 ; k 2 ; k r thus obtained can be shown to be minimal [4], thereby guaranteeing that minimal time is spent on each subscriber and maximum number of subscribers are serviced during a service round. However, the computational overhead of such an algorithm can be prohibitive. We propose a Quality Proportional Multi subscriber Servicing (QPMS) algorithm, in ....

D. P. Anderson, Yoshitomo Osawa, and Ramesh Govindan. Real-Time Disk Storage and Retrieval of Digital Audio and Video. Technical Report No. UCB/CSD 91/646, Computer Science Division, University of California, Berkeley, California 94720, August 8, 1991.

....projects have begun investigating storage issues in digital multimedia systems. The Cambridge Pandora project [10] and Matsushita s Real Time Storage System [14] Designing an On Demand Multimedia Service 3 have begun investigating low level storage mechanisms for digital video. Anderson et al. [2] and Gammell et al. [7] have described file system designs for supporting multiple audio channel playback, and have proposed techniques for providing hard performance guarantees. A model for the design of a file system for storing real time video and audio streams individually on magnetic disks ....

D. Anderson, Y. Osawa, and R. Govindan. Real-time Disk Storage and Retrieval of Digital Audio and Video. To appear in the ACM Transactions on Computer Systems.

....example, a MPEG 1 compressed video object requires a 1.5 megabit per second (Mb s) bandwidth. A MPEG 2 compressed video object may require a bandwidth ranging from 4 to 15 Mb s depending on the resolution used to compress data. A stereo CD quality audio object has a 1. 4 Mb s bandwidth requirement [2]. To display an object X , it is partitioned into f subobjects: X 1 , X 2 , X f (see [20] for the computation of the size of a subobject) The time to display a subobject is termed a time interval. Once object X is referenced, its display employs a cycle based approach: the system stages the ....

D. Anderson, Y. Osawa, and R. Govindan. Real-time disk storage and retrieval of digital audio and video. UCB/ERL Technical Report M91/646, UC Berkeley, 1991.

....requirements. 1 Introduction In recent years, the design of mass storage systems for multimedia applications has become an active research topic [1, 2, 3, 4, 5, 13] One of the most important applications of multimedia storage systems is ondemand playback of video or high quality audio programs [3, 4, 6, 7, 8, 9, 10, 11, 12, 13]. In on demand playback applications, the storage system supports concurrent retrieval of continuous video or audio programs requested by a large number of clients. Such applications impose two major challenges to mass storage system design: 1. High data retrieval bandwidth The data retrieval ....

D. Anderson, Y. Osawa, and R. Govindan. Realtime disk storage and retrieval of digital audio and video. Technical report, U.C. Berkeley, September 1991. UCB Technical Report.

....sequence is changed, it is necessary that the following data block be delivered to the customer within a very short time to preserve the feel of interactivity. In this paper, we address this problem of achieving short, specifically sub second, response times for these requests. Recent work [3, 1, 4, 5, 6] has looked at disk scheduling in a video server. File systems for handling continuous media have been proposed [7, 8, 9, 10] Pause resume and reverse forward type interactivity is addressed in some of the recent work [11, 12, 13] Most of this work on interactivity is concerned about the impact ....

D. P. Anderson, Y. Osawa, and R. Govindan. Real-time disk storage and retrieval of digital audio/video data. Tech. report UCB/CSD 91/646, Univ. of Cal., Berkeley, Aug. 1991.

....respectively when we use f(N i ) N i =Nmax Gamma 1. When these requests are served by their modified deadlines, they are served in the track order. A request with a later deadline will be served after these three requests are served. Other researchers have proposed similar scheduling policies [12, 13, 2]. 3.2 Buffer space tradeoff Available buffer space has a significant impact on the performance of the system. Real time requests typically need some kind of response before the next request is issued. Hence, the deadlines for the requests are made equal to the periods of the requests. The ....

....time available for serving a given request allows more opportunities for it to be served in the scan direction. This results in more efficient use of disk arm and as a result, larger number of request streams can be supported at a single disk. A similar technique called work ahead is utilized in [12]. Scheduling algorithms for real time requests when the deadlines are different from the periods are reported in [14, 15] 10 Chapter 1 Both these techniques, larger requests with larger periods and delayed deadlines, increase the latency of service at the disk. When the deadlines are delayed, ....

D. P. Anderson, Y. Osawa, and R. Govindan. Real-time disk storage and retrieval of digital audio/video data. Tech. report UCB/CSD 91/646, Univ. of Cal., Berkeley, Aug. 1991.

No context found.

D. P. Anderson, Y. Osawa, R. Govindan. Real-Time Disk Storage and Retrieval of Digital Audio/Video Data. TR UCB/CSB 91/646, University of California, Berkely, September 1991.

No context found.

D. P. Anderson, Y. Osawa, and R. Govindan. Real-time disk storage and retrieval of digital audio/video data. Tech. report UCB/CSD 91/646, Univ. of Cal., Berkeley, Aug. 1991.

No context found.

Ande91. Anderson, D.P., Osawa, Y., and Govindan, R. Real-Time Disk Storage and Retrieval of Digital Audio and Video. Tech. Rept. UCBTR-91-646, UCB, 1991.

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