On the other thing, since you seem to be talking about re-arranging the priority of his different programs, yeah? Which I'm not sure is actually something that happens in computers, since they work on everything more or less equally at the same time as I understand it, so probably either term would be equally valid.

With unix based systems you can give some processes higher priority (more cycles per second) manually as well as automatically. Windows does it in a more hands off manner, when you do things like convert wav files to mp3 or rip CDs "in the background" you're telling windows it's okay to give the programs you are actively using a higher priority if they need it.