[307,20] README.1ST U.S. Geological Survey, Menlo Park, California, submissions to the Spring 1986 DECUS Tape. This material was discussed in the presentation "Fortran-77 Performance and Optimization Issues" at the Dallas Symposium. Contents of this UIC: F77VBUG.DOC Description and correction to Fortran-77 V5.0 OTS which causes Virtual Array problems with I/D Tasks. VIRT.MAC Experimental "Fast Virtual Array" package. This code is CRVIRT.MAC meant to replace standard Virtual arrays when performance DSVIRT.MAC or Virtual Array index limitations need to be stretched. DSWIND.MAC Allows creation of one or more regions, and performs TEST.FTN manual mapping to the region through any arbitrary common TESTBLD.CMD block. Once mapped, array accesses to the "Virtual array" are as fast as normal array accesses. Look at the source files and the test program for details. GETVIR.MAC Map and return the virtual address of a Virtual Array element BLKIO.FTN Virtual disk I/O routines from Fortran-77. Allows you to read and write disk blocks directly into arrays (regular OR Virtual!) using direct QIOs. Uses the GETVIR routine for accessing Virtual Arrays. A MUST for reducing disk I/O overhead for an application. See the source files for details.