Continuous Retrieval of Multimedia Data Using Parallelism

Abstrut-Multimedia information systems have emerged as an essential component of many application domains ranging from library information systems to entertainment technology. This is because these systems utilize a variety of h-an senses to provide an effective means of communicating information. However, most implementations of these systems (based on a workstation) cannot support a continuous display of high resolution audio and video data and suffer from fkequent disruptions and delays termed hiccups. This is due to the low U0 bandwidth of the current disk technology, the high bandwidth requirement of multimedia objects, and the large size of these objects which mquks them to be almost always disk resident. In this paper, we describe a parallel multimedia information system and the key technical ideas that enable it to support a real-time display of multimedii objects. These techniques are as follows. First, we decluster a multimedia object across several disk drives, enabling the system to utilize the aggregate bandwidth of multiple disks to retrieve an object in real-time. Second, the workload of an application is distributed evenly across the disk drives in order to maximize the processing capability of the system. To support simultaneous display of several multimedia objects for different users, we describe two altemative approaches. The first approach multitasks a disk drive among several requests while the second replicates the data and dedicates resources to each individual request. We investigate the trade-offs associated with each approach using a simulation model. Our results demonstrate the superiority of the replication approach.