Visualizing initial condition files can sometimes be problematic. OM3 files, for example, are straight binary data files on 16 bit data. However, these files can be quickly visualized with Adobe Photoshop. View this tutorial to find out how:

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Since I get many questions on what's contained in FOAM output, here's a list of all the variables contained in the standard atmosphere, coupler, and ocean output files.

When not using a scheduler like Torque/PBS, it can be complicated to find out whether the model has quit. If the run was successful, you can have a reasonable idea when it SHOULD quit, but it might crash long before that time. As a result, you've lost hours, if not days, of computing time.

At last, the new machine is now doing production work and I've run almost 24 hours so far. First, it's running a bit slower than anticipated, about 13.5 model years per day. I'm not sure what's causing the slower speeds, but it's still an acceptable speed considering my original estimate was only 7 model years per day.

Temperature remains a worry for me. The CPU temps seemed reasonable, but the RAM temps seemed rather high for long-term processing. So, I ordered some fans to cool the RAM boards.

Now that the model clearly works using the test license from Portland, it's time to rebuild the system. So far, I've reinstalled MacOS onto the system and installed the developer tools.

Next, I installed required version control software. At this point, subversion and cvs are already on the system so I only needed to install GIT.

The next step in the process is to migrate my subversion and git repositories to the new system and get the servers going.

One misgiving about running a climate model on the mac is that I don't trust linux to handle the Mac's fans to keep the mac cool. Apparently, there is even more to it. The mac also will throttle memory bandwidth if the ram gets too hot (see technote TN2156). Whether or not a Linux install not targeted to a Mac would handle these issues, I don't know.

All those worries seem to be moot, however. I managed to get the model running within Leopard. The next few posts will concern some of the details of how this was accomplished.

The minimum ram requirement for the climate model was 2 gig, which is what came with the computer. However, I decided to get 8 more gig for the system. At first, I left the original 2 gig in the machine (arranged according to the docs). However, this caused an enormous performance hit: the system was 12% slower running the model. Dropping the original 2 gig brought the speed back up, more or less, to my original performance figures. I'm still not sure that this was a memory arrangement problem or a mixed-card-size problem...

After attempting a slightly longer R15 run on the model, the performance stayed about the same. It runs at approximately 72 model years per day. I was hoping for more, but that's quite respectable.

Currently, I'm running my first T42 simulation. I was guessing I would get 7 years per day for this run. I was using a fairly linear CPU comparison with Gondwana, my older cluster, which uses 16 2 ghz Opteron processors, comes in just under 10 years per day.

After a long struggle trying to work with various compilers, today, I decided to try the Portland C/Fortran compilers. I've had success with them before. Fortunately for me, it worked! I actually got the model running at a low resolution! Tomorrow, I'll try a high resolution.

Computer clusters can be expensive to buy and expensive to maintain. My current linux cluster has 18 CPUs, and takes up about 13U of rack space in a colocation facility, and uses 17-18 amps of power.