IBM 610 workstation computer 3398

People I know who have access to supercomputers or is doing research on supercomputer technology tell me that plenty of the grunt work is still done in Fortran, albeit mostly HPF or Fortran 9x. There is, however, plenty of programs that was written years ago that still have to be maintained, such as hydrological models, et cetera. Many of these are written in Fortran 77 or even Fortran IV.

Quite a lot of work is also done in straight C or C++, often using libraries for message pbutting, such as MPI or targeting virtual machines such as PVM. There is also, believe it or not, people doing these things in Java.

Quite a few of researchers actually using supercomputers these days program in some higher level language to express their simulation. One example is Modelica. Using the Modelica compiler on their code, they generate C code which is fed to a compiler for the supercomputer-cluster, whatever.

Another take is to express your problem in a higher level language and then compile the code to a VHDL or Verilog model and generate net lists to feed into an FPGA available direclty on the supercomputer. SGI, for example, have models with integrated slightly C-like in syntax, uses a Java-based compiler(!) and outputs VHDL, if I understand it correctly.

MC