MCSR

Sweetgum is an SGI Origin 2800 Supercomputers equipped with 128 CPUs, 64 gigabytes of memory, and 1.6 Terabytes of fiberchannel disk. Half of the processors are R12000's cl ocked at 300MHz. The other half are 195 MHz R10000's. The word size is 64 bits.

Operating System

Sweetgum runs the IRIX operating system (6.5.3). IRIX is a UNIX-derived operating system with SGI extensions. The current operating system version number may be found on-line with the comman d uname -R.

IRIX Compilers, Development Tools, and Applications

Several compilers are available on the Origin 2000: FORTRAN (f77, f90), C (cc) and C++ (CC). The compilers provide optimization to take advantage of the architectural features of the machine.

Available applications include Gamess, Gaussian 03, IMSL, MPICH, and Patran.

Parallel Processing

There are two methods for taking advantage of multiple processors on the Origin 2800. The first, multiprocessing, happens by default. That is, as many programs as there are processors can be executing in parallel. The second method, multi-tasking, occurs when two or more processors work together to run a single program. It is possible to multi-task FORTRAN, C and C++ programs on the Origin 2800. To achieve multitasking, the programmer can insert explicit compiler directives into the source code. As an alternative, the "-pfa" option with FORTRAN codes enables the Power Fortran Accelerator. This will create an executable that has been automatically parallelized. Finally, programmers may use the MPI or OpenMP libraries on sweetgum to parallelize their code explicitly.