openMosix in action: An example

openMosix clusters can take various forms. To demonstrate this, let's assume you are a student and share a dorm room with a rich computer science guy, with whom you have linked computers to form an openMosix cluster. Let's also assume you are currently converting music files from your CDs to Ogg Vorbis for your private use, which is legal in your country. Your roommate is working on a project in C++ that he says will bring World Peace. However, at just this moment he is in the bathroom doing unspeakable things, and his computer is idle.

So when you start a program like bladeenc to convert Bach's .... from .wav to .ogg format, the openMosix routines on your machine compare the load on both nodes and decide that things will go faster if that process is sent from your Pentium-233 to his Athlon XP. This happens automatically: you just type or click your commands as you would if you were on a standalone machine. All you notice is that when you start two more coding runs, things go a lot faster, and the response time doesn't go down.

Now while you're still typing ...., your roommate comes back, mumbling something about red chili peppers in cafeteria food. He resumes his tests, using a program called 'pmake', a version of 'make' optimized for parallel execution. Whatever he's doing, it uses up so much CPU time that openMosix even starts to send subprocesses to your machine to balance the load.

This setup is called *single-pool*: all computers are used as a single cluster. The advantage/disadvantage of this is that your computer is part of the pool: your stuff will run on other computers, but their stuff will run on yours too.