CMOS Advanced Menu

The Advanced menu is for setting advanced features that are available through the motherboard chipset. This part of your BIOS setup is specific to the particular chipset the motherboard uses.

Many chipsets are available on the market today, and each has unique features. The chipset setup is designed to enable the user to customize these features and control some of the chipset settings. Right now, one of the most popular chipsets is the Intel 845PE chipset.

PCI Configuration

Submenu The PCI Configuration submenu is used to select the IRQ priority of add-on cards plugged into the PCI slots. Auto (the default) should be used to allow the BIOS and operating system to assign IRQs to each slot unless specific PCI cards require unique IRQs.

Additional Advanced Features

Many boards differ in the advanced chipset menus. In most cases, unless you know exactly which chipset and what type of memory and other items are found in your system, it is best to leave these settings on Auto. In that case, the modern boards use the configuration ROM found on the DIMM or RIMM memory modules to properly configure the memory settings.

In fact, many newer boards no longer allow these settings to be manually adjusted because, in most cases, all that does is lead to trouble in the form of an unstable or a failing system.

If you do want to play with these settings, I recommend first finding out exactly which memory modules and chipset you have and contacting the manufacturers of them to get their databooks. The databooks have all the technical information related to those devices.

Peripheral Configuration

The Peripheral Configuration menu is used to configure the devices built into the motherboard, such as serial ports, parallel ports, and built-in audio and USB ports.

IDE Configuration Submenu

The IDE Configuration submenu is for configuring IDE devices, such as hard drives, CD-ROM drives, LS-120 (SuperDisk) drives, tape drives, and so on. The hard disk pre-delay function is to delay accessing drives that are slow to spin up.

Some drives aren't ready when the system begins to look for them during boot, causing the system to display Fixed Disk Failure messages and fail to boot. Setting this delay allows time for the drive to become ready before continuing the boot. Of course, this slows down the boot process, so if your drives don't need this delay, it should be disabled.

IDE Configuration Submenus

These submenus are for configuring each IDE device, including primary and secondary masters and slaves. Of all the BIOS Setup menus, the hard disk settings are by far the most important. In fact, they are the most important of all the BIOS settings. Most modern motherboards incorporate two IDE controllers that support up to four drives.

Most modern BIOSs have an autodetect feature that enables automatic configuration of the drives. If this is available, in most cases you should use it because it will prevent confusion in the future. With the Auto setting, the BIOS sends a special Identify Drive command to the drive, which responds with information about the correct settings.

From this, the BIOS can automatically detect the specifications and optimal operating mode of almost all IDE hard drives. When you select Auto for a hard drive, the BIOS redetects the drive specifications during POST, every time the system boots.

You could swap drives with the power off, and the system would automatically detect the new drive the next time it was turned on. In addition to the Auto setting, most older BIOSs offered a standard table of up to 47 drive types with specifically prerecorded parameters.

Each defined drive type has a specified number of cylinders, number of heads, write precompensation factor, landing zone, and number of sectors. This often was used many years ago, but it is rarely used today because virtually no drives conform to the parameters on these drive type lists.

Another option is to select a setting called User or User Defined, which is where you can enter the specific drive CHS (Cylinder, Head, and Sector) parameters into the proper fields. These parameters are saved in the CMOS RAM and reloaded every time the system is powered up.

Most BIOSs today offer control over the drive translation settings if the type is set to User and not Auto. Usually, two translation settings are available, called Standard and LBA. Standard or LBA-disabled is used only for drives of 528MB or less, where the maximum number of cylinders, heads, and sectors are 1,024, 16, and 63, respectively.

Because most drives today are larger, this setting is rarely used. LBA (logical block addressing) is used for virtually all drives that are larger than 528MB. Note that systems dating from 1997 and earlier usually are limited to a maximum drive size of 8.4GB unless they have a BIOS upgrade.

Systems from 1998 and later usually support drives up to 136.9GB; systems dating from 2002 and beyond usually support drives beyond 137GB, although a BIOS upgrade might be necessary. During drive accesses, the IDE controller transforms the data address described by sector, head, and cylinder number into a physical block address, significantly improving data transfer rates.

Setting the drive type to Auto causes the other values to be automatically configured correctly. I recommend this for virtually all standard system configurations. When set to Auto, the BIOS sends an Identify command to the drive, causing it to report back all the options and features found on that drive.

Using this information, the BIOS then automatically configures all the settings on this menu for maximum performance with that drive, including selecting the fastest possible transfer modes and other features. For hard drives, the only option available other than Auto is User.

When set to User, the other choices are made available and are not automatically set. This can be useful for somebody who wants to "play" with these settings, but in most cases, all you will get by doing so is lower performance and possibly even trouble in the form of corrupted data or a nonfunctional drive.

User should be used only if a drive was originally prepared with a set of values different from those recognized automatically with the default Auto configuration setting.

Diskette Configuration

Submenu The Diskette Configuration submenu is for configuring the floppy drive and interface. By enabling the write-protect feature, you can disallow writing to floppy disks. This can help prevent the theft of data as well as help to prevent infecting disks with viruses should they be on the system.

Event Logging

The Event Logging menu is for configuring the System Management (SMBIOS) event logging features. SMBIOS is a DMI-compliant method for managing computers on a managed network. DMI stands for Desktop Management Interface, a special protocol that software can use to communicate with the motherboard.

Using SMBIOS, a system administrator can remotely obtain information about a system. Applications such as the LANDesk Client Manager (originally developed by Intel but now sold by LANDesk Software) can use SMBIOS to report the following DMI information:

  • BIOS data, such as the BIOS revision level

  • System data, such as installed peripherals, serial numbers, and asset tags

  • Resource data, such as memory size, cache size, and processor speed

  • Dynamic data such as event detection, including event detection and error loggi

Some motherboards with ECC memory also support log ECC events. I find event logging particularly useful for tracking errors such as ECC errors. Using the View Log feature, you can see whether any errors have been detected (and corrected) by the system.

Video Configuration

The Video Configuration menu is for configuring video features. The most common use of this menu is to change the primary video device. This is useful under Windows 98 and later versions, which support dual-monitor configurations. Using this feature, you can set either the AGP or PCI video card to be the primary boot device.

USB Configuration Submenu

The USB Configuration submenu is used for configuring the USB ports on the system. Some motherboards that have separate USB 1.1 and USB 2.0 ports might offer additional configuration options. Legacy USB support means support for USB keyboards and mice.

If you are using USB keyboards and mice, you will find that the keyboard is not functional until a USB-aware operating system is loaded.

This can be a problem when running DOS; diagnostics software; or other applications that run outside of USB-aware operating systems, such as Windows 98, Windows Me, Windows XP, and Windows 2000. In that case, you should enable the USB legacy support via this menu.

Even with legacy support disabled, the system still recognizes a USB keyboard and enables it to work during the POST and BIOS Setup. If USB legacy support is disabled (the default on some systems), the system operates as follows:

  1. When you power up the computer, USB legacy support is disabled.

  2. POST begins.

  3. USB legacy support is temporarily enabled by the BIOS. This enables you to use a USB keyboard to enter the setup program or Maintenance mode.

  4. POST completes and disables USB legacy support (unless it was set to Enabled while in Setup).

  5. The operating system loads. While the operating system is loading, USB keyboards and mice are not recognized. After the operating system loads the USB drivers, the USB devices are recognized.

To install an operating system that supports USB, enable USB legacy support in BIOS Setup and follow the operating system's installation instructions. After the operating system is installed and the USB drivers are configured, USB legacy support is no longer used and the operating system USB drivers take over.

However, I recommend that you leave legacy support enabled so the USB keyboard functions in DOS while running self-booting or DOS-based diagnostics or when running other non-USB-aware operating systems. If USB legacy support is enabled, you shouldn't mix USB and PS/2 port keyboards and mice.

For example, don't use a PS/2 keyboard with a USB mouse or a USB keyboard and a PS/2 mouse. Also remember that this legacy support is for keyboards and mice only; it won't work for USB hubs or other USB devices. For devices other than keyboards or mice to work, you need a USB-aware operating system with the appropriate USB drivers.

Fan Control Configuration Submenu

Most systems have one or more chassis fans to help cool the system.

Resource Configuration/PnP Configuration Menu

If you have a motherboard with one or more ISA slots, you need to use the Resource Configuration or PnP Configuration menu to determine which IRQs and memory addresses are available for ISA devices. This is not necessary on motherboards that have only PCI or PCI and AGP slots.