The Core of Configuration

In the movies, when the heroine wakes up with amnesia, she puts a hand to her brow and breathes, “Where am I?” When you push your PC’s power switch each morning, the machine not only has amnesia but needs to ask, “What am I?” — for that first millisecond, it doesn’t even know it’s a PC, let alone that it has X amount of memory, such-and-such type and size of hard disk, and should stay alert for your keyboard and mouse input.

The tool that kick-starts your computer, “teaching” it its configuration, how to access memory, and so on, is the BIOS (basic input/output system) — one of the most essential, powerful, and potentially confusing parts of any PC. The BIOS keeps track of the most integral system settings, and serves as a sort of preflight check when you first boot — ensuring that your hardware is working properly, and adjusting your system profile and informing the operating system if any new components have been added. It also plays a vital role in CPU performance. This article will present the BIOS basics you need to know before considering any system upgrade.


Stored as firmware in a memory chip, the BIOS program reads — and, when changes are made, writes or updates — the system configuration info stored in a CMOS (complementary metal oxide semiconductor) RAM chip on the motherboard. A small lithium battery (which usually lasts for years) lets the low-power CMOS chip store configuration settings and the system date and time even when the PC’s turned off. (Though it’s not technically correct, the acronyms are often used interchangeably; i.e., the utility that lets you make changes is referred to as both a “BIOS setup screen” and “CMOS setup screen.”)

At startup, the BIOS uses the stored settings and its own programming to identify the available hardware — the CPU, memory size and speed, disk drives, and so on. A power-on self-test (POST) tests the RAM and other hardware and warns of any changes, inconsistencies, or problems.

Once the BIOS has finished its job, the computer is essentially a blank slate that allows any compatible operating system to be loaded — Windows XP, Linux, or an old DOS boot disk you’ve got lying around. Since the BIOS initializes the hardware, there doesn’t even have to be an operating system per se; some newer motherboards have a nifty feature that can play music CDs right after the BIOS loads. This illustrates how versatile a PC can be, as the BIOS is like an open door to allow virtually any subsequent software to work with the installed hardware.

Usually, of course, you’re using a conventional operating system; once the OS loads, most BIOS functions fade into the background. Since Windows 95, Plug and Play technology has done a lot to minimize resource allocation to the system BIOS, as the operating system takes control of the resident hardware and takes over the job of recognizing peripherals added later (i.e., those that need not be active at boot time, like a digital camera plugged into a USB port).

Entering the BIOS and Editing Your Configuration

We should say up front that the vast majority of users will never need to fool around in the BIOS. CPU and memory upgrades, operating system refreshes, and new external peripherals are all reasons for BIOS/CMOS adjustment, but today’s BIOS routines’ high level of auto-detect features will handle most alterations. If your system is running well, repeat after us: If it ain’t broke, don’t fix it.

In the event that BIOS settings do need to be adjusted, you usually initiate the process by pressing a key during startup. The key used varies from system to system, with Delete, Esc, F2, and F10 among the popular choices; often a “Press [your key here] to enter Setup” message flashes on the screen for a few seconds at boot time. Due to user support and warranty issues, some system manufacturers have implemented relatively hidden or disabled BIOS setup programs, and a bit more detective work may be required to access these.

One last warning: When it comes to changing any BIOS setting, prepare for the worst — a frozen or unbootable PC — and have a rescue plan. Most motherboards offer another keystroke option to reset the BIOS and enable a boot with default settings. In the realm of worst-case scenarios, there’s a physical jumper on the motherboard that can perform the reset (as always, power off before messing with motherboard components), or you can resort to the tried-and-true method of removing and then reinserting the CMOS battery before turning the system back on.

BIOS Menus and Options

There’s no one standard for system BIOS design, though there are many constants. The BIOS setup firmware usually present a number of screens or sections, each with many different potential names but similar functions.

The first menu contains basic system configuration items such as the system date and time, the floppy drive(s), the primary and secondary IDE devices, and the amount of system memory. Since this hardware is usually auto-detected, it’s a good idea to check this screen after upgrading, just to make sure that extra RAM is listed or that new hard disk or CD burner is recognized. Not seeing upgraded hardware in this screen is a dead giveaway that something went wrong with your installation.

The Advanced BIOS or Advanced Chipset area features a wider array of options, with the most important relating to boot preferences, mouse/keyboard settings, BIOS caching, and some system security settings. You might use the choices found here to rearrange the order of storage devices tried at startup (if you need to bypass the hard disk and boot a Windows installation or emergency-utility CD); enable or disable PS/2 or USB peripherals; or set a system password.

Next comes Power Management, a part of the BIOS that usually doesn’t need to be adjusted on a functioning PC — the ACPI (Advanced Configuration and Power Interface) spec gives control of the power-management and Plug and Play devices to the operating system, so the Control Panel or system-tray-icon power-management settings in current versions of Windows take precedence. You might also see the infamous “Restore on Power Loss” menu choice, which if set to “restore” (rather than “off”), can cause a system to reboot upon exiting Windows.

Another menu that should be ignored if your PC’s running smoothly is PCI Configuration. There’s usually an entry here for Plug and Play OS, which if set to “yes” will give PCI resource configuration to the operating system. Unless you’ve recently installed a PCI video card, or are having problems with a new PCI card, leave well enough alone. You can force IRQs to specific PCI slots, but this should only be done as a last resort when Windows refuses to properly allocate resources and conflicts arise.

The Integrated Peripherals menu is an important one, because it lets you enable or disable various built-in features of the motherboard. With the high number of integrated features in today’s motherboards (even performance models as well as the economy variety), it’s quite common to see users boot their systems and have to wait for a unused RAID controller to auto-detect devices, or Windows to load and repeatedly ask for a mystery driver.

The motto here is “If you don’t use ’em, lose ’em” — disable any RAID, motherboard- rather than expansion-card-mounted audio or video, FireWire port, or other feature that you don’t need, eliminating the need for a driver and freeing system resources. Just make sure you know which ports and peripherals are active and essential, as opposed to just taking up space.

PC Health Status is a real gearhead section of the BIOS, where under-the-hood temperatures, cooling fan speeds, and voltage levels are displayed. For most users, these are useless numbers, but for the hardcore enthusiast — specifically, the CPU overclocker — knowing exactly at which core voltage a Pentium 4 is running can be vital information. The same goes for temperature levels, as running a PC out of spec can create chip-frying heat and monitoring temperatures can help determine overall system tolerances.

Danger! Experts Only!

The last (or first, in some BIOS menus) area is the most arcane, but also the most intriguing, most powerful, and potentially most dangerous of all. It goes by many names, but we’ll call it the Frequency/Voltage Control screen. Here, the overclockers come and play, tweaking voltages and memory and CPU speeds in search of performance gains (or at least bragging rights).

Many times, the initial or factory settings of a PC are rather conservative, and if you know your hardware, resetting them to take full advantage of installed components — for instance, running DDR333 or PC2700 memory at 333MHz rather than 266MHz — can yield a noticeable speed boost. For others, it’s a matter of ripping up the warranty and jacking processor speeds to the maximum, such as turning a 1.8GHz CPU into a 2.4GHz screamer with a few basic adjustments.

Again, this section is deadly dangerous for inexperienced users, and we recommend further research — beyond the scope of this introductory article — into the various settings and the interdependencies between them. For example, raising the CPU clock speed usually requires an increase to the core voltage, which in turn results in higher processor and system heat levels. An incorrect or overly ambitious setting can result in system instability, corrupt data, or permanent hardware damage, so plan before you play, and even then, tread lightly.

Upgrading the BIOS

Ancient PCs kept their BIOS firmware in ROM chips that had to be physically removed and replaced for a new version, but current systems use flash EEPROM (electrically erasable programmable read-only memory) that can be upgraded by running a software utility.

Depending on the manufacturer, there are several methods used to perform a flash BIOS update, ranging from the trusty DOS boot disk to sophisticated Windows utilities and neophyte-oriented update Web sites. The last one is sort of worrisome (i.e., carrier dropped in the middle of an update); with the release of Windows XP, most vendors have moved to a graphical interface where the program confirms the update and loads the new BIOS file seamlessly.

Even with today’s much safer methods, a BIOS update is not without risk; a power outage or data corruption can lead straight to a Return Materials Authorization call to your dealer. Motherboard and BIOS vendors usually post firmware updates to support new hardware or fix bugs in very specific configurations; if you don’t require a BIOS update, then don’t install it. It’s as simple as that.

Like the Windows Registry for software settings, the system BIOS can be a powerful tool for PC users who understand its inner workings and stick to safety-first practices, with a recovery or contingency plan prepared in case of problems. Jump in with both feet, however, and you might have a Jurassic Park on your hands, and a Jeff Goldblum-like support guy telling you how foolish you were to attempt it in the first place.

Categories: Technology