Server and Desktop Differences
The differences between the two editions are the lack of an X window environment in the Server Edition, the installation process, and different Kernel options. Kernel Differences:
• The Server Edition uses the Deadline I/O scheduler instead of the CFQ scheduler used by the Desktop Edition.
• Preemption is turned off in the Server Edition.
• The timer interrupt is 100 Hz in the Server Edition and 250 Hz in the Desktop Edition.
Trecho adaptado do guia de instalação do Ubuntu 11.10
Fonte: https://help.ubuntu.com/11.10/serverguide/preparing-to-install.html
A palavra "Preemption", no texto, pode ser traduzida como: