Standard Setup
This is the most commonly changed section of the CMOS setup. When you first go into your CMOS setup, this is the first option available to you. Hit Enter to go into "Standard CMOS Setup".

Here's a rundown of the options:

Date (mm:dd:yy):
Used to set the system date.

Time (hh:mm:ss)
Set the system clock. You may want to do this every once in a while. The system clock is not the most accurate clock in the world.

Hard Disks
Usually, this will be a little table showing all installed IDE hard disks and their settings. Typically, these settings are all set to Auto, meaning the BIOS senses the settings automatically for you. In some BIOS, though, you may need to do this yourself. Three options are usually allowed. These are "Auto", "User", or "None". "User" means that you will specify the hard disk settings yourself. "None" means that you are telling the computer there is no hard disk on that IDE channel.

Note: Since some knowledge of hard drive structure is needed to understand these settings, you can go to the hard drive section to find the info.

If set to "User", the settings are:

Size: Usually set automatically depending on the settings for heads, sectors, and cylinders.
Cylinders: The number of cylinders on hard disk. Should be written on drive.
Heads: Number of heads. Should be written on drive.
Write precompensation: Not much used on modern drives. It was used to accomodate drives that had the same number of sectors per track, including both the inner and outer tracks. On SCSI drives, set this to -1. On IDE drives, it is not necessary to worry about it as it will be determined automatically.
Landing zone: Used for drives that don't have auto-parking. All modern drives do, so just set to 0.
Sector: Number of sectors per track. It's often 17 for MFM drives, and 26 for RLL drives.
Floppy Drive A
Used to choose the type of floppy drive you are using for Drive A. The most common setting is 1.44M, 3.5", but you should change it depending on your hardware.

Floppy Drive B
Same as Floppy Drive A. If you only have one floppy drive, set this setting to NONE.

Primary Display / Video
Choose the type of video display adapter you use. Most commonly set to VGA. If you have two video cards, use the primary display to dictate this setting.

Keyboard
If you do not have a keyboard installed, this option tells the BIOs to skip the keyboard test in the POST. this is useful for computers such as servers that may be booted without a keyboard.

Halt On
Tells the BIOS which errors to skip in the POST. For example, if you want the BIOS POST to continue whether or not it gets an error on a missing keyboard, set this to "All, but keyboard".

The Basics

As mentioned in the introduction, the BIOS is the core to the operation of your PC. It is the framework for your computer to be able to run the rest of its software. It performs the POST, or Power On Self Test. This is the sequence of system checks the BIOS goes through every time your turn on your system.

The BIOS is what underlies the operating system. In a way, the operating system is a simplified user-interface to the BIOS. This is of course rather exaggerated, since the OS is also very core to your system. But, without the BIOS, the operating system does not do anything. For instance, when you hit a key on your keyboard, the processor performs an interrupt to read that key. This interrupt is handled by the BIOS, which assigns and manages the interrupts. This is similar for other components on the system, which also operate by interrupts. By using this method, the processor is able to conduct many jobs at once in regards to other hardware.

BIOS is often confused with CMOS. The two are often, and mistakenly, thought of to be one and the same. Actually, CMOS, which stands for Complementary Metal Oxide Semiconductor, is the little 64 byte piece of RAM which stores the settings for the BIOS to work off of. It is because of the CMOS that the BIOS remembers your PC's configuration and is able to load it properly upon each boot-up. The CMOS resides in a small integrated circuit, or IC, found on your motherboard. The memory is maintained by a small current generated by a battery which also resides on your motherboard. Newer board use a NiCad battery which recharges whenever the PC is on, but the older ones use a standard battery, which when it runs out of juice, must be replaced. In a similar fashion, if you wish, for some reason, to clear your CMOS and start fresh, simply disconnect the battery. Of course, on newer boards, there is a CMOS-clear jumper, usually located near the battery, which performs the same function.

BIOS Setup

The BIOS setup is an area where you can configure your computer based on the hardware that is in it. It allows you to change the BIOS settings, which in turn changes the way the BIOS configures your chipset.

BIOS setup has been complicated by the growing complexity of computer hardware. As new technology comes out, the BIOS too must grow to support them. This combines with the problem of little standardization. since there are many BIOS makers, as well as many chipset and motherboard makers, the whole scene has been quite complicated. The BIOS setup, therefore, is really not well documented in most motherboard manuals. In some cases, technicians themselves find themselves baffled by some of the settings availible in the BIOS setup.