@Article{davis:rle, author = {G. Davis and L. Lau and R. Young and F. Duncalfe and L. Brebber}, title = {Parallel Run-Length Encoding {(RLE)} Compression---Reducing {I/O} in Dynamic Environmental Simulations}, journal = {The International Journal of High Performance Computing Applications}, year = {1998}, month = {Winter}, volume = {12}, number = {4}, pages = {396--410}, note = {In a Special Issue on I/O in Parallel Applications}, keywords = {parallel I/O application, compression, pario-bib}, abstract = {Dynamic simulations based on time-varying inputs are extremely I/O intensive. This is shown by industrial applications generating environmental projections based on seasonal-to-interannual climate forecasts which have a compute to data-access ratio of O(n) leading to significant performance degradation. Exploitation of compression techniques such as Run-Length-Encoding (RLE) significantly reduces the I/O bottleneck and storage requirements. Unfortunately, traditional RLE algorithms do not perform well in a parallel-vector platform such as the Cray architecture. This paper describes the design and implementation of a new RLE algorithm based on data chunking and packing that exploits the Cray gather-scatter vector hardware and multiple processors. This innovative approach reduces I/O and file storage requirements on average by an order of magnitude. Data intensive applications such as the integration of environmental and global climate models now become practical in a realistic time-frame.}, comment = {In a Special Issue on I/O in Parallel Applications, volume 12, numbers 3 and 4.} }