BIOS Guide

BIOS (basic input/output system) is the program a personal computer's microprocessor uses to get the computer system started after you turn it on. It also manages data flow between the computer's operating system and attached devices such as the hard disk, video adapter, keyboard, mouse and printer.

BIOS is an integral part of your computer and comes with it when you bring it home. (In contrast, the operating system can either be pre-installed by the manufacturer or vendor or installed by the user.) BIOS is a program that is made accessible to the microprocessor on an erasable programmable read-only memory (BIOS Guide) chip. When you turn on your computer, the microprocessor passes control to the BIOS program, which is always located at the same place on BIOS Guide.

When BIOS boots up (starts up) your computer, it first determines whether all of the attachments are in place and operational and then it loads the operating system (or key parts of it) into your computer's random access memory (RAM) from your hard disk or diskette drive.

With BIOS, your operating system and its applications are freed from having to understand exact details (such as hardware addresses) about the attached input/output devices. When device details change, only the BIOS program needs to be changed. Sometimes this change can be made during your system setup. In any case, neither your operating system or any applications you use need to be changed.

Although BIOS is theoretically always the intermediary between the microprocessor and I/O device control information and data flow, in some cases, BIOS can arrange for data to flow directly to memory from devices (such as video cards) that require faster data flow to be effective.

What are the common BIOS settings, and what do they really signify and actually do for you?

If you've ever spent time tweaking your system, chances are you've played around in the motherboard's BIOS settings. You sift through the options, only to find a massive laundry list of settings you can tweak, with many of them these days defaulted to "Auto." Chances are, you won't ever have to touch these settings. But if you're looking to expand your knowledge on what these settings do and when you should tweak them, this guide's for you!

A note about manufacturers and how they organize options

Not every manufacturer organizes these settings in the same manner. Fortunately, the organization a company uses is usually the same regardless of the platform. Below is where these options lay for four popular manufacturers from their recent BIOS settings organization.

The typical BIOS set-up program is intimidating in the extreme, packed with technical options that could badly damage your PC if you don't use them correctly. And so most people make do with the default settings.

That approach guarantees your system will work, but it also means that it will never deliver its best performance. Learn a little more about the options on offer and BIOS tweaking won't seem as scary.