Giving Linux the Boot
Face it: As enjoyable as the experience of staring at a dormant computer is, the real fun starts when you turn it on. As with any electronic device, opening the electron floodgate is the first step to fun. A computer, however, can do much more stuff than your toaster oven. Rather than warm up a simple heating element, your computer has to check all those gizmos that you (or the manufacturer) plugged into your computer’s motherboard. After the initial power-up, the computer performs some simple hardware tests (called the POST, or Power-Up Self-Test) to determine whether those various components are working properly.
Checking all your hardware is just the beginning. Between the time you turn the computer on and the moment the glowing phosphor on your monitor prompts you for a login name, the computer is building itself an empire. If you listen and watch carefully, your computer and monitor show you signs of the boot process through bleeps, buzzes, whirring motors, clicks, messages on the monitor, and blinking lights.
Although you have heard the cliché “Rome wasn’t built in a day,” the boot process goes fairly quickly. This is pretty amazing, considering that the architecture of an operating system makes Rome’s look like a stack of cardboard boxes; each time you power up your computer, it must build its whole operating system in memory. (Remember that an operating system is the core software that makes your computer work.) This process can be broken into four ...