| Summary: | 碩士 === 國立中正大學 === 資訊工程學系 === 84 === VoD(Video on Demand) services will be widely available in the
masscommunication. In order to support such high data retrieval
rate tomeet multimedia applications need, the I/O system
becomes an impor-tant issue in the design of the storage server.
In this thesis, we propose a new hierarchical architecture
designof storageserver for huge multimedia data based on PC-
based platforms.By taking the great advantages from DMA(Direct
Memory Access) and em-ploying a split transaction technique in
SCSI-2 protocols, our storageserver can handle the disk I/O and
network transfer at much full pa-rallelism. We also introduce
the object-oriented concept in the designof system resource
control, including memory management and job queuecontrol. At
the system level, we employ two main techniques to supporthigh-
performance I/O subsystem: reordering and reducing data copy.
Re-quests can be reordered at the system scheduling level and
the devicedriver level. A way of memory remapping totally
reduces unnecessarydaua copy between system and device drivers,
or system and networkdrivers. We evaluate our system by
actually measuring the system throughputand response time for
each request. Our performance results show thatwith the
condition of four disks on two Wide SCSI buses and 10Mbytescache
buffer, the system can support at most 42 clients with the net-
work overhead.
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