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If the data stored on CMOS about a particular piece of hardware (or about its fancier features) is different from the specs of the actual hardware, the computer cannot access that piece of hardware (or use its fancier features). It is crucial that this information be correct. If you change any of the previously mentioned hardware, you must update CMOS to reflect those changes. You need to know, therefore, how to change the data on CMOS.

Updating CMOS: The Setup Program

Every PC ships with a program built into the system ROM called the CMOS setup program or the system setup utility that enables you to access and update CMOS data. When you fire up your computer in the morning, the first thing you likely see is the BIOS information. It might look like the example in Figure 7-12 or perhaps something like Figure 7-13.

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NOTE The terms CMOS setup program, CMOS, and system setup utility are functionally interchangeable today. You’ll even hear the program referred to as the BIOS setup utility or CMOS setup utility. Most techs just call it the CMOS.

Figure 7-12 AMI BIOS information

Figure 7-13 Award/Phoenix BIOS information

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NOTE Okay, I’ve thrown a whole bunch of terms at you describing various pieces of hardware and software and what does what to whom. Here’s the scorecard so you can sort out the various pieces of data.

1. The system ROM chip stores the system BIOS, programs needed by the CPU to communicate with devices.

2. The system ROM chip also holds the program that accesses the information stored on the CMOS chip to support changeable pieces of hardware. This program is called the CMOS setup program or the system setup utility.

3. The CMOS holds a small amount of data that describes the changeable pieces of hardware supported by the system BIOS. The CMOS today is in the Southbridge chip of the chipset.

Who or what is AMIBIOS, and who or what is Phoenix Technologies? These are brand names of BIOS companies. They write BIOS programs and sell them to computer manufacturers. In today’s world, motherboard makers rarely write their own BIOS. Instead, they buy their BIOS from specialized third-party BIOS makers such as Award Software and Phoenix Technologies. Although several companies write BIOS, two big companies control 99 percent of the BIOS business: American Megatrends Incorporated (AMI) and Phoenix Technologies. Phoenix bought Award Software a few years ago and still sells the Award brand name as a separate product line. These three are the most common brand names in the field.

You always access a system’s CMOS setup program at boot. The real question is how to access the CMOS setup at boot for your particular PC. AMI, Award, and Phoenix use different keys to access the CMOS setup program. Usually, BIOS manufacturers tell you how to access the CMOS setup right on the screen as your computer boots up. For example, at the bottom of the screen in Figure 7-13, you are instructed to “Press DEL to enter SETUP.” Keep in mind that this is only one possible example. Motherboard manufacturers can change the key combinations for entering CMOS setup. You can even set up the computer so the message does not show—a smart idea if you need to keep nosy people out of your CMOS setup! If you don’t see an “enter setup” message, wait until the RAM count starts and then try one of the following keys or key combinations: DEL, ESC, F1, F2, CTRL-ALT-ESC, CTRL-ALT-INS, CTRL-ALT-ENTER, or CTRL-S. It may take a few tries, but you will eventually find the right key or key combination. If not, check the motherboard book or the manufacturer’s Web site for the information.

A Quick Tour Through a Typical CMOS Setup Program

Every BIOS maker’s CMOS setup program looks a little different, but don’t let that confuse you. They all contain basically the same settings; you just have to be comfortable poking around. To avoid doing something foolish, do not save anything unless you are sure you have it set correctly.

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