Minimum system requirements for GEOS-Chem
Several GEOS-Chem users have asked "What type of machine do I need to buy in order to run GEOS-Chem?" Here are our suggestions.
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Hardware Recommendations
Our hardware recommendations are:
- enough memory to run GEOS-Chem
- at least 2 GB RAM
- but more than 4 GB RAM for running at 2x2.5
- If you are going to be running GEOS-Chem with high-resolution nested grids (e.g. 1 x 1 global grid or 0.5 x 0.667 nested grids), then you may want to consider upgrading to 8GB RAM.
- sufficient disk storage for met fields.
The more diagnostics you save out the more memory it will require.
The Linux flavor (RedHat, SuSE, Fedora, Ubuntu, etc.) is not important. Also, 64-bit architecture is not an issue with GEOS-Chem.
Can GEOS-Chem run on Microsoft Windows (XP, Vista, etc.)?
No. You will need to run GEOS-Chem in a Unix or Linux environment.
However, GEOS-Chem should be able to run in Mac OS Leopard, which is 100% compatible with Unix. As of Mar 2007, we are not aware of anyone having done this yet.
Which compilers does GEOS-Chem support?
At present GEOS-Chem supports the following compilers:
| Compiler | Platform(s) |
|---|---|
| SGI MipsPro compiler | SGI Origin SGI Power Challenge |
| Intel Fortran compiler (IFORT) (versions 9, 10) | SGI Altix Itanium Linux machines Sun X4100/Linux |
| Portland Group International (PGI) | Linux machines |
| SunStudio Fortran compiler (versions 11, 12) | Sun X4100/Solaris Sun X4100/Linux |
| IBM AIX compiler | Older IBM machines |
For Linux, we strongly recommend to use the Intel Fortran (IFORT) compiler. In our experience, we have found that the Intel compiler is just a better all-around compiler than PGI. We have had various minor compatibility problems with PGI. Also, the Intel compiler is available at relatively low cost to you if you work for an educational institution.
The latest version of Intel (10.x) is very optimized for multi-core chipsets.
Parallelization
Also, you should be aware that because GEOS-Chem uses OpenMP parallelization, you can only run on as many nodes as are shared by the memory. For example, if you had 2 PC's, and each PC w/ 4 cores each, then you can only run on 1 PC at a time (i.e. 4 cores). This is because OpenMP has a requirement that all of the processors on the machine must be able to see all of the memory on the machine. In that case, you could run 2 jobs simultaneously on 4 cores, but not a single job on 8 cores. See www.openmp.org for more information.
MPI (Message Passing Interface) is required for passing memory from one physical system to another. The current version of GEOS-Chem does not yet have this capability.
How much disk space will I need for GEOS-Chem?
It will depend on which type of met data (GEOS-4 or GEOS-5) that you will use, and how many years of data you will download. Typical disk space requirements are:
| Data type | Size |
|---|---|
| GEOS-4 4x5 met (uncompressed) | ~13 GB/yr |
| GEOS-4 2x25 met (uncompressed) = | ~52 GB/yr |
| GEOS-5 4x5 met (uncompressed) | ~30 GB/yr |
| GEOS-5 2x25 met (uncompressed) = | ~120 GB/yr |
