P. Lougher and D. Shepherd. "The Design and Implementation of a Continuous Media Storage Server ". Proceedings of the 3rd International Workshop on Network and Operating System Support for Audio and Video (November 1992).  Home/Search   Document Not in Database   Summary   Related Articles   Check

....contract number E30602 97 2 0287 and in part under contract number F30602 96 1 0160. Mr. Molano was funded by a research grant from the Community of Madrid and by the National R D Program of Spain under contracts TIC96 0982 and TIC97 0438. one type (namely network packets) Work described in [1, 2, 7, 8] study various aspects of real time disks and filesystems. The approach used in [1] is a variation of the Scan algorithm in which the SCAN direction changes towards the Earliest Deadline First request only if the deadline is considered to be met. At any scheduling point the request with the ....

P. Lougher and D. Shepherd. "The Design and Implementation of a Continuous Media Storage Server ". Proceedings of the 3rd International Workshop on Network and Operating System Support for Audio and Video (November 1992).

....than the peak bandwidth could used by an ATM network user. There has been similar research on the management of temporal characteristics of data retrieval from a rotating storage device. These systems are divided into ones that advocate a specific layout on the hard disk for optimal retrieval [14, 53] and those that only use hard disk characteristics and buffering techniques for time bounded retrievals [80, 78] While multimedia data delivery across an ATM or from a hard disk can be integrated into a multimedia presentation system, they all rely on being implemented in conjunction with ....

Lougher, P. and D. Shepherd, "The Design and Implementation of a Continuous Media Storage Server," Proc. Third International Workshop on Network and 119 Operating System Support For Digital Audio and Video, San Diego, California, November 1992, pp. 63-74.

....focussed on the development and implementation of hardware designed to handle continuous multimedia between host machines and a multi service network. The projects in which this research has been conducted are the Multimedia Network Interface (MNI) Scott, 91] the Continuous Media Storage Server [Lougher, 92] and the Local Area Network on a Chip (LANC) Scott, 93] So far the systems developed have not been reproducible on a large scale due to the cost of the hardware. The most prominent example of this is the Pandora project [Hopper, 90] at Olivetti Research and Cambridge University where each box ....

Lougher, P. and D. Shepherd, "The Design and Implementation of a Continuous Media Storage Server", Proc. Third International Workshop on Network and Operating Systems Support for Digital Audio and Video, San Diego, California, November 1992, pp.6374.

....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 retrieving ....

P. Lougher and D. Shepherd. The Design and Implementation of a Continuous Media Storage Server, Network and Operating System Support for Digital Audio and Video. In Proceedings of the 3rd International Workshop, La Jolla CA, pages 69--80. Springer Verlag, 1992.

.... been studied extensively as early as [Fra69] and [TP72] Ful75] More recently [AGM90] and [ea91] have addressed the problem in the context of real time systems(RTS) With the growing interest in continuous media server design recent work by [Gem93] RW93] CKY93] AOG92] RV93a] GC92] LS92] RVG 93] CCP 94] DS94] CL93] has been very significant. While [GC92] presents a general theory of retrieval for continuous media there have been two distinct approaches to the retrieval problem at the CMS. First, approaches like [RW93] RVG 93] KB93] DS94] adapt scheduling ....

....improvement greatly influenced our choice of incorporating batching and SCAN features into our scheduling strategy. However, their scheduling approaches do not address issues typical of CM data like handling frame oriented streams. In the second approach, like those in [Gem93] CKY93] AOG92] LS92] RV93a] CL93] the effort has been to derive new scheduling strategies that are aware of the continuous and real time requirements of a CMS. Our work draws heavily on work from the second approach. RV93a] proposes a fixed order cyclical scheduling strategy. Their analysis has inspired some ....

P. Lougher and D. Shepherd. Design and implementation of a continuous media storage server. In Proc. of 3 rd Intl. Workshop on Network and Operating Systems, 1992.

....acceptance test for new sessions, and disk scheduling policy. However, disk allocation was assumed clustered or non clustered for uncompressed audio data. The model was again byte level based and the storage ordering assumed to be is the same as the retrieval ordering. Lougher and Shepherd s work [11, 12] on the design of a storage server for continuous media was originally designed for a multiple disk system. Again, the disk allocation was assumed clustered or non clustered and the model was byte level based and the storage ordering assumed to be is the same as the retrieval ordering. 8 ....

P. Lougher and D. Shepherd. The design and implementation of a continuous media storage server. Proceedings of the Third International Workshop on Network and Operating System Support for Digital Audio and Video, pages 69--81, Nov 1992.

....the optimal response time algorithm in a class of active accumulation strategies. Simulation studies are used to validate analytical results presented here. 1. 2 Relation to Previous Work The problem of designing a scheduling strategy for CM data has been previously addressed in [RV93] CL93] LS92] AOG92] RVG 93] KEL94] Gem93] GC92] CKY94] TPBG93] Servicing strategies like [CKY93] RW93] and [Gem93] use single buffers while allowing head scheduling algorithms like C SCAN to decide the servicing order. Using single buffers can restrict the subscribers consumption ....

....They discuss the relationship between slack and the response time of concurrency set operations, which they denote as start up latency . A key difference between our work and [TPBG93] is that our strategy provides playback guarantee at all time besides supporting an extended suite of operations. LS92] discusses support for Pause, Stop, Play operations, besides Open and Close. However, they do not provide playback guarantees while such operations are being executed. Concurrent with our work on supporting VCR like operations like FastForward and ReversePlay are [CKY94] and [DSKT94] By ....

P. Lougher and D. Shepherd. Design and implementation of a continuous media storage server. In Proc. of 3 rd Intl. Workshop on Network and Operating Systems, 1992.

....well as the capacity of the CMS since it reserves resource commensurate with the clients playback quality. The efficacy of QBSCAN is demostrated via simulation studies. 1. 2 Relation to Previous Work Strategies to schedule accesses to the CMS is being widely researched [7] 4] 1] 17] 8] [16], and [5] Work examining the nature of Quality of Service for CM data can be found in [18] 23] 2] Recently, 15] 21] 6] 20] and [24] have attempted to devise strategies that reserve statistically estimated bandwidth instead of worst case to handle compressed data. Some approaches ....

P. Lougher and D. Shepherd. Design and implementation of a continuous media storage server. In Proc. of 3 rd Intl. Workshop on Network and Operating Systems, 1992.

....disks have a constant data transfer rate and that the size of contiguously read data units (blocksets) is larger or equal to a single track, thereby enabling access cycles without rotational latency. Various strategies exist for serving multiple strands simultaneously. One may for example, as in [2] define a fixed repetitive time frame called round, within which one blockset per served strand is accessed and transferred into its respective buffer. To respect deterministic isochronicity constraints, the sum of disk access times for all the n accessed blocksets should be smaller than the ....

....time and increasing the global sustained throughput. k R f i In the approach we propose, we assume that we serve our n strands repetitively during m successive cycles. We define one cycle as the time it takes to serve one blockset per strand. Instead of waiting, as in other schemes [2], until the buffered blocksets of the previously read access cycle have been displayed, we continue accessing the disk for m successive cycles. Since track locations of strand blocksets are equiprobable, we can establish the probability density distribution for the head displacement. We then ....

P. Lougher, D. Shepard, "The Design and Implementation of a Continuous Media Storage Server", Proc. 3rd International Workshop on Network and Operating System Support for Digital Audio and Video, Nov 92, LNCS 712, Springer Verlag, 1993, 6980

....directly (using Fore or ORL ATM cards) or via our proprietary MEND network. The MEND network is a high speed mini cell (6 octets) switching network with a potential bit rate of 100Mbps. The multimedia storage server is a high capacity device composed of two large disk bricks using RAID technology [Lougher, 92] This storage server is central to our experimentation as it will store many compressed images and sound for the support of distributed multimedia applications. Compression of these images and sound is achieved through the use of real time MPEG and JPEG encoders. These real time encoders, ....

Lougher, P. and D. Shepherd, "The Design and Implementation of a Continuous Media Storage Server", Proc. Third International Workshop on Network and Operating Systems Support for Digital Audio and Video, San Diego, California, November 1992, pp. 63-74.

....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 with ....

P. Lougher and D. Shepherd. The Design and Implementation of a Continuous Media Storage Server, Network and Operating System Support for Digital Audio and Video. In Proceedings of the 3rd International Workshop, La Jolla CA, pages 69--80. Springer Verlag, 1992.

....of digital video and audio in Section 2.1 and describe the model of the storage system in which the compositions will be stored in Section 2.2. In Section 3 we present our solutions and their evaluations in Section 4. Section 5 presents our conclusions. Previous work in this area includes[LS92] CL93] GR93] ONWC87] RV93] YSB 89] CKY94] FC91] GC92] YSB 89] and [RV93] discuss supporting synchronized retrieval without maintaining distinct storage for components of a composition. GR93] considers the storage of such data in disk arrays to increase retrieval bandwidth. ....

....P Delta Delta Delta B in inter frame compressed MPEG video) sequenced in a pre defined order at (say) 30 frames per second. A composite stream, on the other hand, is composed temporally 1 from other (simple or composite) streams. Constructs like those proposed in [Rea91] LG90] and [KKHLS92] allow specification of temporal relationships between time intervals of play out of the component streams. Such sets of constructs are useful for specifying compositions as well as deriving placement for two reasons. Firstly, it is far too cumbersome 2 to specify temporal relationships ....

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P. Lougher and D. Shepherd. Design and implementation of a continuous media storage server. In Proc. of 3 rd Intl. Workshop on Network and Operating Systems, 1992.

....device; we do not consider RAID or other data distribution approaches in this context. A number of related works exist in this area. The problem of satisfying timing requirements for multimedia data has been studied as a conceptual database problem [11] as an operating system delivery problem [1, 12, 13, 22], as a physical disk modeling problem [6, 9, 10, 18] and as a physical data organization and performance problem [5, 7, 8, 14, 21, 23, 24] Rangan et al. 16] propose a model for storing real time multimedia data in file systems. The model defines an interleaved storage organization for ....

....device is analyzed with respect to the mean and variance of the seek latency. disk track block i video audio text reserved Figure 1: Physical Storage Organization for a Rotating Disk Device A round robin scheduling discipline is chosen for the service of multimedia sessions as in other work [12, 14, 17], permitting the disk to switch alternately between multimedia tasks and other non real time tasks. The file system achieves a high disk bandwidth utilization by assigning long disk reads or writes and thus sharing the seek and latency delays among a large number of bits read or written, resulting ....

Lougher, P., and D. Shepherd, "The Design and Implementation of a Continuous Media Storage Server," Proc. 3rd Intl. Workshop on Network and Operating System Support for Digital Audio and Video, San Diego, November 1992, pp. 63-74.

.... techniques of 1:5 Mb=s; 3 Mb=s and 6 Mb=s rates, image qualities that are near VHS VCR, NTSC Entertainment video, and NTSC Studio video, respectively, can be achieved Several architectural configurations for efficient and reliable storage and delivery of video data have been proposed and utilized [1, 2, 4, 8, 11, 16, 19, 22, 9]. Some of these works address only the configurability of the system components while others address only the support of small numbers of video streams, in the magnitude of less than 10,000. Although it is arguable that the DVDSs are relatively in their infancy, it is necessary that current ....

P. Lougher, D. Shepherd, "The design and implementation of a continuous media storage server," Proc. Third Intern. Workshop on Network and Operating System Support for Audio and Video, La Jolla, CA., Nov. 12-13, 1992, pp. 69-80.

....the priority of the media handling tasks [48] In a multi user environment, reservations have been used to guarantee the availability of resources for a real time application. Real time file systems have been designed that guarantee a lower bound on bandwidth for sequential access to a file [46, 61, 5]. The RealTime Mach operating system allows virtual memory pages to be pinned down to avoid page faults [79] Processor bandwidth may be reserved for periodic real time tasks [51, 61] Network bandwidth reservation protocols have been described and implemented [22, 2, 86] A reservation protocol ....

Lougher, P., and Shepherd, D. The design and implementation of a continuous media storage server. In Third International Workshop on Network and Operating System Support for Digital Audio and Video (San Diego, California, November 1992), IEEE Computer Society, pp. 63--74. 116

....must handle a number of concurrent users accessing simultaneous multimedia streams and index structures. The large data requirements of continuous video along with its isochronous nature stretch beyond the capabilities of current file Servers. There are a number of research groups, including [15, 16, 17, 18, 19], that have started investigating the issues in developing a high performance multi media server Shared Control Mechanisms: The current environment restricts many control functions (e.g. image manipulation, pointing, image capture) to the base site and instructor. In the future it is desirable ....

P. Lougher and D. Shepherd. Design and implementation of a continuous media storage server. In Proc. of 3 rd Intl. Workshop on Network and Operating Systems, 1992.

.... in computer technology and demand of video, audio, graphics, and text integration services have provided driving force behind the emergence of various multimedia applications including teleconferencing, computer supported coorperative work, multimedia electronic mail, and computer aided learning[1, 2]. Most of today s multimedia playback applications are standalone and not distributed. This is due to the limitations of networks and storage servers. Thus, remote multimedia playback applications have given a technical challenge with regards to real time transmission, storage, and retrieval of ....

..... 3 Design of Real Time Storage Server As mentioned in Section 1, a real time storage server must have high performance storage system. To satisfy this constraint, we adopt disk array architecture, modeled on the level 5 RAID which distributes the data and check information across all 1 In [1], this assumption is called normalized stream and in [5] heterogeneous stream . the disks[8] RAID 5 shows a good performance for read operation[9] thus is considered the most suitable model for the read intensive storage server. Its justification is discussed in detail in Section 4. The ....

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P. Lougher and D. Shepherd, "The design and implementation of a continuous media storage server," Proc. 3rd International Workshop on Network and OS Support for Digital Audio and Video, San Diego, California, pp. 63--74, Nov. 1992.

....the CM server, CM data is transported to its clients via a LAN or a WAN network. With today s hardware technology, designing schemes to schedule concurrent access requests to the storage system of a CM server is expected to be a critical task. A consensus amongst researchers in this area ( RV93] LS92] AOG92] CL93] indicates that this task is vital to providing various CM data services to clients. This focus is a result of what is being labelled as the I O bottleneck problem where the storage devices are fast becoming the bottleneck in a computer system [IEE94] Hence, system resource ....

....throughput per access request increases with the block size. Indeed this effect has been independently observed as: ffl Improved performance in storage systems with disk arrays, where a larger logical block is striped across a disk array. This effect has been observed by previous work [GR93] LS92] ffl Improved throughput in storage systems with larger block sizes while storing larger data types like full motion video [LS92] Example As an example, consider a CM server with a high performance disk, whose disk transfer rate is 1 GBps. If each of the clients were retrieving ....

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P. Lougher and D. Shepherd. Design and implementation of a continuous media storage server. In Proc. of 3 rd Intl. Workshop on Network and Operating Systems, 1992.

....server was built at Lancaster. This enables multiple audio and video streams to be stored and retrieved in real time. This work will continue with new versions of the server designed around the LANe system and its associated ATM interfaces allowing far greater numbers of simultaneous connections [Lougher,92] Lougher,93] A further area of interest is the ongoing development of a simplified multimedia system supporting the same protocols at the LANC system described in this paper. The aim of this system is to allow the production of tens of multimedia systems, which due to cost is not feasible ....

Lougher, P., Shepherd, W.D., "The Design and Implementation of a Continuous Media Storage Server", Proc. Third International Workshop on Network And Operating Systems Support For Digital Audio and Video, San Diego, California, November 1992, pp.63-74.

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P. Laugher and D. Shepherd. Design and implementation of a continuous media storage server. In Proc. of 3 d Intl. Workshop on Network and Operating Systems, 1992.

No context found.

P. Lougher, D. Shepherd, The design and implementation of a continuous media storage server, Proc. Third Intern. Workshop on Network and Operating System Support for Audio and Video, La Jolla, CA., Nov. 12-13, 1992, pp. 69-80.

No context found.

P. Lougher and D. Shepherd. "Design and Implementation of a Continuous Media Storage Server." In Proceedings of the 3rd International Workshop on Network and Operating System Support for Digital Audio and Video, 1992.

No context found.

P. Lougher and D. Shepherd, "The Design and Implementation of a Continuous Media Storage Server," Proceedings of the 3rd International Workshop on Network and Operating System Support for Digital Video and Audio, Nov. 1992.

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