The Scheduling menu brings up a small dialog that allows you to tinker with the way A-Shell shares the CPU with other applications on your PC. The default foreground and background priority is "13", which is measure of how long A-Shell will "hog" the CPU before intentionally yielding to another application. In general, you can ignore all of this, particularly NT, W2000 and XP, since all but the most CPU-intensive applications will yield to other applications due to the need to wait for peripheral operations.