FDS and Computer Speed

[Kevin McGrattan <kevin.mcgrattan@nist.gov>]

All

I've been getting more inquiries lately about computers,
compilers, operating systems, etc. I thought I would
broadcast some general impressions.

FDS is written in Fortran 95, mainly, with just a few
non-standard features (a buffer flushing routine that is
understood by most compilers, and calls to C routines that
are also understood by most). So FDS should be compilable by
most Fortran compilers which have access to a C compiler. I
use the Compaq Digital Fortran compiler to create the
release Windows version of FDS. I compile FDS on a Dell
Windows/Intel XP laptop with the recommended level of
optimizations. For those of you who are thinking of buying a
PC with, for example, a 64 bit architecture, or some
different type of CPU from Intel, or whatever, you may have
to compile FDS yourselves to get the advertised speed-up in
performance. I do not have access to all of the different
types of PCs and all the different types of compilers. I
would NOT expect the released binary executable (fds4.exe)
to run optimally on the newest generation of CPUs. I'm also
not in a position to say what machine works best. This is
something that you should determine for yourselves by
creating a simple test case, compiling FDS, then running the
test case.

That being said, I'd be interested to know if anyone has
successfully compiled a 64 bit version of FDS and then run a
very large (RAM greater than 4 GB) single processor
calculation.

Kevin

 
-- 
Kevin McGrattan
National Institute of Standards and Technology
100 Bureau Drive, Stop 8663
Gaithersburg MD 20899-8663

Telephone: (301) 975 2712
FAX:       (301) 975 4052