@Article{simitci:patterns, author = {Huseyin Simitci and Daniel Reed}, title = {A Comparison of Logical and Physical Parallel {I/O} Patterns}, journal = {The International Journal of High Performance Computing Applications}, year = {1998}, month = {Fall}, volume = {12}, number = {3}, pages = {364--380}, keywords = {parallel I/O application, pario-bib}, abstract = {Although there are several extant studies of parallel scientific application request patterns, there is little experimental data on the correlation of physical input/output patterns with application input/output stimuli. To understand these correlations, we have instrumented the SCSI device drivers of the Intel Paragon OSF/1 operating system to record key physical input/output activities and have correlated this data with the input/output patterns of scientific applications captured via the Pablo analysis toolkit. Our analysis shows that disk hardware features profoundly affect the distribution of request delays and that current parallel file systems respond to parallel application input/output patterns in non-scalable ways.}, comment = {In a Special Issue on I/O in Parallel Applications, volume 12, numbers 3 and 4.} }