A. Hopper, Pandora -- An Experimental System for Multimedia Applications, Olivetti Research Laboratory report, 1990.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....background, message corpus and experiment design, and presents experimental results showing audio retrieval performance very close to that of text. 1 Introduction The last few years has seen an increasing use of multimedia applications, including video conferencing and video and audio mail [1]. Using these facilities can create large archives of video material, which poses a significant storage and retrieval problem. Users are unable to find stored messages because, unlike text, there are no simple ways to search for a particular reference. The Video Mail Retrieval (VMR) project is ....

A. Hopper. Pandora - an experimental system for multimedia applications. In ACM Operating Systems Review, April 1990.

....of a network based video source for a distributed ATM environment. These properties relate to functionality and ATM control mechanisms. Video capture boards have been proposed designed for other research based distributed multimedia systems similar to the ViewStation. In the Pandora system [7], a multimedia box containing a video capture board is loosely coupled to a workstation. Black and white video in a variety of picture sizes is transmitted between boxes over a dedicated high speed network. In the Desk Area Network Project [6] an ATM network based capture board with minimal ....

Hopper, A. Pandora - An Experimental System for Multimedia Applications. A CM Operating Systems Review 2J, 4 (Apr. 1990), 19-34.

....include sophisticated protocol processors which also aim to offioad the transport protocol handling from the main workstation processor onto the network interface itself. The system bearing closest comparison with the Lancaster MNI unit is Pandora s Box, which was developed by Olivetti Research [Hopper,90] Pandora is an add on unit for Unix workstations and offers comparable functionality to the MNI unit. The Pandora and MNI systems are more than simply protocol processors; they offer full end to end multimedia support. Whereas the first generation MNI unit relies mainly on off the shelf ....

Hopper, A., "Pandora - An Experimental System for Multimedia Applications", ACM Operating Systems Review, Vol 23, No 2, April 1990.

....of a network based video source for a distributed ATM environment. These properties relate to functionality and ATM control mechanisms. Video capture boards have been proposed designed for other research based distributed multimedia systems similar to the ViewStation. In the Pandora system [7], a multimedia box containing a video capture board is loosely coupled to a workstation. Black and white video in a variety of picture sizes is transmitted between boxes over a dedicated high speed network. In the Desk Area Network Project [6] an ATM network1 ## # ## # # ## # # ## # # ## # # # ....

Hopper, A. Pandora - An Experimental System for Multimedia Applications. ACM Operating Systems Review 24, 4 (Apr. 1990), 19-34.

....resources, to system support for real time programming. 2.4.1 Specialized hardware One approach to supporting real time multimedia applications is to dedicate hardware to the tasks that must be performed in real time. This relieves any contention for resources. As an example, Pandora s Box [44] was an early attempt to support multimedia applications in the context of a desktop workstation. The box contained six transputers, each one dedicated to a particular activity or class of activity including audio processing, storage disk management, video processing, decompression, network ....

....from mechanisms for guaranteed resource reservation. Many multimedia cards and co processor boards and boxes are actually embedded systems with their own processors and operating systems. These systems must manage resources for multiple real time activities that must be multiplexed. Hopper [44] described Pandora s Box which is a transputer system designed to be a multimedia peripheral for a traditional workstation. The Pandora system employs several transputers, each of which handles a particular function in the system such as compression, decompression, network traffic, and audio. A ....

A. Hopper. Pandora - an experimental system for multimedia applications. ACM Operating Systems Review, 24(2):19--34, April 1990. 152

....and current status. Keywords: ATM, distributed systems, multimedia systems, network architecture, host interfaces, host I O, device drivers 1 Introduction In many research based and commercial multimedia systems, multimedia tasks are centralized around a workstation (or personal computer) [6, 12]. Data is passed among the different workstation components including the hard disk, processor, frame buffer, and add in multimedia boards on the I O bus. In the case of these distributed applications, the workstation serves as a focal point for organizing the communication of multimedia ....

.... design of distributed multimedia systems (video and audio) has evolved from systems based on the parallel combination of an analog media distribution system and a networked computer system [3, 5] to all digital systems where real time media and traditional computer data share common resources [6, 12, 11]. Most of the current all digital systems are workstation centric in that they consist of networked workstations with add in multimedia cards that connect to the I O bus. These systems have many disadvantages which limit their use; the systems are often tailored for teleconferencing type ....

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A. Hopper, "Pandora - An Experimental System for Multimedia Applications," ACM Operating Systems Review, 24 (2), April 1990.

....general purpose multi user operating system designed to maximise the service to applications from such hardware. 1 1.1 Context Previous research has been done in Cambridge in the field of Continuous Media applications. Much of this has been practical with the implementation of the Pandora s Box [Hopper90], a continuous media peripheral for a workstation. Such facilities are typically used in a distributed environment [Nicolaou90] Storage and synchronisation services have been implemented for the Pandora system which used an early ATM network known as the Cambridge Fast Ring [Temple84] The ....

A. Hopper. Pandora -- an experimental system for multimedia applications. ACM Operating Systems Review, 24(2):19--34, April 1990. (p 2)

....for clients wishing to locate network services. This is achieved by servers informing the Trader of their services. Clients initiate connections with network services after contacting the Trader for service location information. Real time audio and video streams are provided by the Pandora Box [Hopper90]. This is a multi media peripheral which is attached to a general purpose workstation. The main components include a video digitiser, a video mixer, an audio processing board and a CFR network interface. Audio and video are digitised and processed separately from the host processor. The resulting ....

....control, guaranteed continuous access, flow control and network bandwidth management are not addressed and no performance characteristics are available. 2. 6 Olivetti Research Video Repository The Olivetti Research Laboratory developed a continuous media file repository for project Pandora [Hopper90]. The repository is built over TRIPOS and its FH5 filing system. The configuration consists of an Acorn R260 (30MHz ARM3 processor) 16 MBytes RAM, a CFR interface and a SCSI interface serving 4 Wren 6 drives offering a storage space of 2.5 GBytes. This approach is another example of using a ....

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A. Hopper. Pandora - An experimental system for multimedia applications. ACM Operating Systems Review, 24(2), April 1990. (pp 4, 14, 28, 64)

....(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 (one per office) costs around 12,000. The Multimedia Enhancement Network Device (MEND) reported in this paper aims to give multimedia networked functionality at a reduced cost. Obviously to maintain the low cost a reduction in ....

Hopper, A., "Pandora - An Experimental System for Multimedia Applications" Operating Systems Review, Vol. 24, No. 2, April 1990.

....many workstations are incapable of handling the large data volumes which are involved, due to limitations on data copying, bus bandwidth and device access. Perhaps the earliest project to demonstrate the benefits of running continuous media applications in a workstation environment is Pandora [Hopper90, Hopper92, King92] which is a component of the experimental apparatus used in Chapter 5. Pandora minimises many of the aforementioned problems by adopting a hybrid approach, in that continuous media are handled within a special purpose Transputer based computer. This is equipped with a camera ....

....between users in these applications is impaired. The ISLAND project found that values up to 125ms are acceptable [Ades87] for telephone conversation, equivalent to the 100ms to 150ms range which is recommended for the public telephone system [Campbell92b] Experience with the Pandora system [Hopper90] reported in [Campbell92b] led to the observation that an audio delay greater than 10ms was noticeable without the use of echo suppression. Video can generally sustain larger values as exemplified by the 230ms estimate in [Jeffay91] but significant delay differences between streams is ....

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A. Hopper. Pandora - An Experimental System for Multimedia Applications. ACM Operating Systems Review, 24(2):19--34, April 1990. (pp 3, 11, 39, 40, 71)

....by continuous media applications. The mechanisms which are required within an operating system to support the multimedia applications are described, and the design and implementation of a prototypical kernel which implements them are presented in this work. The Olivetti Research Pandora project [Hopper 90] has investigated the integration of audio and video in a distributed environment. The high speed Cambridge Fast Ring [Hopper 88] and the Cambridge Backbone Network [Greaves 90] are used for CM traffic transportation between the multimedia workstations and the relevant network storage servers. ....

A. Hopper, "Pandora - An Experimental System for Multimedia Applications, " ACM Operating System Review, April 1990.

....been explicitly designed to support the transmission of high bandwidth, fixed rate data such as continuous media with QOS guarantees alongside traditional data types with bursty transmission rates. The Pandora system is an example of a system that supports continuous media using an ATM network [28,16]. Work has also been done on the problem of supporting QOS guarantees using networks that were not originally designed to support such guarantees. This work has generally been based on the principle of resource reservation. In this approach, applications that wish to transmit data over the ....

.... was provided by specialpurpose telephones that digitized, packetized, and transmitted audio data directly onto an Ethernet [50] Another example of this approach is provided by the Pandora project in which a special purpose device attached directly to the network handles audio and video processing [16,28]. 1.4.3 Approaches that Accommodate Delay Jitter If it is not possible to eliminate delay jitter, or if it is too expensive to eliminate delay jitter, then applications will need to accommodate delay jitter when displaying continuous media frames. Applications accommodate delay jitter by ....

Hopper, A., 1990. Pandora: An Experimental System for Multimedia Applications. ACM Operating Systems Review, vol. 24, no. 2, (April), pp. 19-34.

....chips. While these are now being developed for dedicated purposes, general processing by software on multiprocessor systems will be much more feasible [Leslie93] Some multimedia workstations are implemented by adding multimedia peripheral devices to workstations, for example the Pandora system [Hopper90]. The problem is that such external devices are expensive. Generally it can be expected that the work of multimedia processing should be done by software in processors on workstations. In such an environment, two primary limitations are likely: 1) bus bandwidth; 2) the behaviour of operating ....

Andrew Hopper. Pandora - An Experimental System for Multimedia Applications. ACM Operating Systems Review, 24(2):19-- 34, April 1990. (p 3)

....Cambridge (ALC) and Adaptive Broadband Ltd (ABL) intend to explore these issues via the Cambridge Wireless Broadband Trial. The ALC has a long tradition in building networks to support novel and demanding applications. It pioneered the use of multimedia workstations in the Pandora project [1]. Medusa [2] the successor to Pandora, looked at developing a rich multimedia environment using network multimedia peripherals on a 100 Mbps ATM network. The Wireless ATM project [3] looked at building a wireless system based on ATM technology. This group later spun out as Adaptive Broadband Ltd ....

A. Hopper, "Pandora -- an Experimental System for Multimedia Applications", ACM Operating System Review, April 1990.

....display of live or pre recorded video sequences. These systems do not focus on the computational processing of live video. In general, these provide mechanisms for multimedia data to bypass the application at one or more levels: network, system bus, or device driver protocol stack. In Pandora [15], special purpose hardware is controlled by applications running on a workstation. Pandora s box performs video and audio capture as well as mixing in dedicated hardware attached to the workstation and under workstation control. The output of the box goes directly to the workstation display. ....

A. Hopper. Pandora - An Experimental System for Multimedia Applications. ACM Operating Systems Review, 24(2):19--34, April 1990.

....of the CM streams. At the other hand the dedicated processor must do the RT work now. This processor is probably better equipped to meet the timeliness requirements. We expect this processing to be executed in hardware for a great deal. This has already proved to work within the Pandora project [7]. Shifting the RT obligations from the main processor to the dedicated processor however does not free us from the responsibility of paying attention to the RT aspects of CM stream handling. Also we might want a general purpose processor to intervene in a CM stream in order to do some filtering. ....

Hopper A.: "Pandora, an experimental system for multimedia applications", ACM Operating Systems Review, 24 (2), April 1990, pp. 19-34.

....the set up of these. On the other hand the dedicated processor must do the RT work now. This processor is probably better equipped to meet the timeliness requirements. We expect this processing to be executed in hardware for a great deal. This has already proved to work within the Pandora project [2]. Shifting the RT obligations from the main processor to the dedicated processor however does not free us from the responsibility of paying attention to the RT aspects of CM stream handling. Also, we might want a general purpose processor to intervene in a CM stream in order to do some filtering. ....

Hopper A.: "Pandora, an experimental system for multimedia applications", ACM Operating Systems Review, 24 (2), April 1990, pp. 19-34.

.... Video Custode Audio Custode Flat File Custode MSSA Contexts and Objects Other storage Live Devices Pandora Devices Figure 4: Experimental data environment ffl The traditional services of a distributed environment are available networked workstations using Ethernet and NFS ffl The Pandora system [7] consists of a series of workstations each with camera, microphone, capture and display facilities on top of the usual workstation functionality. A prototype repository has been constructed for the storage and retrieval of Pandora audio and video sequences. Workstations are connected to a high ....

A. Hopper, "Pandora - An Experimental System for Multimedia Applications", ACM Operating Systems Review, Vol. 24(2), April, 1990.

....Cambridge. The Desk Area Network proposes using an ATM switch to interconnect components of a workstation so that all attachments (memory, hard drive etc. communicate using ATM. Pandora is a joint project between Olivetti Research Cambridge and the University of Cambridge Computer Laboratory [10]. This project digitizes video as with other boards, but the digitized video is displayed on the screen in a different manner. The digital information is converted to analog, and this signal is mixed with the actual video signal coming from the host to the screen. This cuts down on the bus ....

A. Hopper, Pandora -- An Experimental System for Multimedia Applications, Olivetti Research Laboratory report, 1990.

....is available, a multimedia mail system. In addition some sites have connected TV or radio tuners as input sources to provide access as a network service. The Olivetti Research Pandora system has coupled this with the storage facility to record and provide the latest news and weather from the TV [Hopper90]. Some systems also allow editing of multimedia documents or presentations . 4 I worked with such a machine based on a Phillips Laser Disc and a BBC Microcomputer in 1983 4. This research has showed that providing video is an important addition to a system. A study by Sun Microsystems of a ....

....interest is the convergence with the internal machine interconnect. Several recent papers have observed this and expect the internal and external speeds to remain similar for some time [Druschel93] Many workstations are now shipped equipped with multimedia peripherals. The Pandora system [Hopper90] illustrates some of the many possibilities that will become available when networked multimedia systems become more common. In these machines there are a large number of data flows between the machine and the network, so the performance of the network interface becomes crucial. Research done on ....

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A Hopper. Pandora - an experimental system for multimedia applications. ACM Operating Systems Review, 1990. (pp 13, 29, 31)

....In recent years, computers have become increasingly able to manipulate non textual data, and applications such as video and voice mail have arisen to take advantage of this new processing capability. A recent experimental system has been Pandora, developed by Olivetti Research Ltd in Cambridge, UK [1]. In the Pandora system, Unix workstations, augmented by cameras and microphones, are connected by a wide bandwidth optical fibre based network, providing facilities for video telephony and messaging. However, in practice, the utility of Pandora has been compromised by the lack of methods for ....

A. Hopper, Pandora -- An Experimental System for Multimedia Applications, Operating Systems Review, Vol. 24,No. 2, April 1990.

....array structure to derive the optimal configuration for specific requirements. Key terms: multimedia, storage system, on demand playback, disk bandwidth, disk array 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, 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 ....

A. Hopper. Pandora - an experimental system for multimedia application. ACM Operating System Review, Vol.24, No.2, April 1990.

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A. Hopper, Pandora -- An Experimental System for Multimedia Applications, Olivetti Research Laboratory report, 1990.

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A. Hopper. "Pandora - an experimental system for multimedia applications". ACM Operating Systems Review, 24(2):19-34, April 1990.

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A. Hopper, "Pandora - an Experimental System for Multimedia Applications," Operating Systems Review, 24(2):19-34, April 1990.

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