Refers to restarting a computer that is already turned on via the operating system. Restarting it returns the computer to its initial state. A warm boot is sometimes necessary when a program encounters an error from which it cannot recover. On PCs, you can perform a warm boot by pressing the Control, Alt, and Delete keys simultaneously. On Macs, you can perform a warm boot by pressing the Restart button.
Also called a soft boot.
Contrast with cold boot, turning a computer on from an off position.
BIOS System Boot Operations Describes what is involved in booting a PC, including a discussion of the steps in the system boot process, and a look at the power-on self-test (POST) that is conducted whenever the system starts up. This page is from "The PC Guide."