Came here for the MOSIX, not disappointed. I worked at a facility that ran it on a small science cluster, and it worked extremely well.
A fun wrinkle: When the Intel C compilers first came out, they had warnings about process migration -- there's an executable mode where the executable checks to see what kind of CPU it's on at launch-time, and then branches to CPU-specific code blocks during the run. This can be dangerous, the check is only done once, so if the CPU type changes in mid-run due to migration to different hardware, Bad Things can happen.
This sounds like the same feature that Intel's C compiler used to "cripple AMD" by switching to a slower code path when it detected that the program was running on a non-Intel CPU.
A fun wrinkle: When the Intel C compilers first came out, they had warnings about process migration -- there's an executable mode where the executable checks to see what kind of CPU it's on at launch-time, and then branches to CPU-specific code blocks during the run. This can be dangerous, the check is only done once, so if the CPU type changes in mid-run due to migration to different hardware, Bad Things can happen.