Large files and the PC GAMESS/Firefly

If you set the fastf option in $SYSTEM group to .true. (this option is turned on by default) and run PC GAMESS/Firefly under OS & filesystem supporting large files, all files handled by FSF routines may have their size up to the native limits of 64-bit filesystems. Otherwise, large files will be automatically split into several smaller chunks.

FSF is an abbreviation of the Fast System Files - a powerful set of fast non-Fortran file I/O subroutines. By default, the FSF subroutines are used by the PC GAMESS/Firefly to perform almost all the file I/O operations.

The DRTFILE sequential access file is always handled by the standard file I/O routines, and its maximum size is restricted to 2Gb because of the limitations of Watcom FORTRAN 77 runtime library. It is very unlikely you'll reach the 2Gb limit on this file...