Browsing by Subject "Magnetic disk storage"

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    ItemOpen Access
    A comparison of logical and physical parallel I/O patterns
    (SAGE Publications Inc., 1998) Simitci, H.; Reed, D. A.
    Although there are several extant studies of parallel scientific application request patterns, there is little experimental data on the correlation of physical I/O patterns with application I/O stimuli. To understand these correlations, the authors have instrumented the SCSI device drivers of the Intel Paragon OSF/1 operating system to record key physical I/O activities, and have correlated this data with the I/O patterns of scientific applications captured via the Pablo analysis toolkit. This analysis shows that disk hardware features profoundly affect the distribution of request delays and that current parallel file systems respond to parallel application I/O patterns in nonscalable ways.
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    ItemOpen Access
    Effect of inverted index partitioning schemes on performance of query processing in parallel text retrieval systems
    (Springer, 2006-11) Cambazoğlu, B. Barla; Çatal, A.; Aykanat, Cevdet
    Shared-nothing, parallel text retrieval systems require an inverted index, representing a document collection, to be partitioned among a number of processors. In general, the index can be partitioned based on either the terms or documents in the collection, and the way the partitioning is done greatly affects the query processing performance of the parallel system. In this work, we investigate the effect of these two index partitioning schemes on query processing. We conduct experiments on a 32-node PC cluster, considering the case where index is completely stored in disk. Performance results are reported for a large (30 GB) document collection using an MPI-based parallel query processing implementation. © Springer-Verlag Berlin Heidelberg 2006.
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    ItemOpen Access
    An evaluation of a client-server real-time database system
    (ACM, 1996) Ulusoy, Özgür
    A real-time database system (RTDBS) can be defined as a database system where transactions are associated with real-time constraints. In this paper, we investigate various performance issues in a RTDBS constructed on a client-server system architecture. In a client-server database management system the whole database is stored on the server disks, and copies of database items can be cached in the client memories. We provide a detailed simulation model of a client-server RTDBS, and present the initial results of a performance work that evaluates the effects of various workload parameters and design alternatives. Index Terms - Real-time database systems, client-server architecture, transaction scheduling, timing constraints.