...

1. Process A has just been scheduled to execute for the first time on machine A. 2. I send a suspend signal to Process A, mostly a SIGSTOP. 3. Then I copy Process A's PCB to machine B. 4. On machine B, I send the continue signal to Process A, mostly a SIGCONT. 5. Whenever Process A needs user input or needs to output something, I cause a trap, mostly with a SIGTRAP (or I could use SIGSTOP here again). I transfer this I/O request to machine A and let the user interact. I send the interaction back to Process A on machine B. I resume Process A on machine B. 6. I continue these steps till Process A has completed execution.

Sounds like just what MOSIX, OpenSSI or Kerrighed already do....

Thanks for the information. It was really helpful.