Configuration Overview The BIOS (basic input/output system) is an important motherboard component. The BIOS has the following functions: Holds and executes POST (power on self test)—the program that identifies, tests, and initializes basic hardware components Holds a basic routine called a bootstrap program that locates an operating system and allows it to load Holds Setup, which is a program that allows device settings to be viewed and managed

Configuration Overview When assembling, troubleshooting, or repairing a computer, a technician must go into a Setup program to configure the system. The Setup program is held in BIOS and through the Setup program you can see and possibly configure such things as how much RAM is in the computer, the type and number of drives installed, where the computer looks for its boot files, the current date and time, and so on. An error message is displayed if the information in the Setup program fails to match the hardware or if a specific device does not work properly.

Configuration Overview There are two main ways to configure your system or an adapter—through the Setup program held in system BIOS or through the operating system. The Setup program is examined first. The jumper blocks and jumpers on a motherboard are much smaller.

The Setup Program Most computers have Setup software built into the system BIOS chip on the motherboard and accessed by specific keystrokes determined by the BIOS manufacturer. During the boot process, most computers will display a message stating which keystrokes will launch the Setup program. The keystroke can be one key pressed during startup such as the –Esc, Ins, Del, F1, F2, or F10 keys. Other BIOS manufacturers use a combination of keystrokes where two or more keys are held down simultaneously during the boot process.

Flash BIOS Flash BIOS is the most common type of BIOS that allows changing the BIOS without installing a new chip or chips. Common computer BIOS manufactures include AMI (American Megatrends,Inc.), Phoenix, and Insyde Software. The following procedure is one example of “flashing the BIOS”: 1. Once the system BIOS upgrade is downloaded from the Internet, execute the update. 2. Follow the directions on the screen or from the manufacturer. 3. Reboot the computer

Flash BIOS There are various reasons why a computer may need a BIOS upgrade: to provide support for new or upgraded hardware, support for higher capacity hard drives, virus protection, password protection, or to solve problems with the current BIOS. Some motherboards have a utility that allows recovery if a BIOS becomes corrupted or the BIOS update fails. Other motherboards come with a Flash recovery jumper or switch used for BIOS recovery. A computer without an operational BIOS cannot boot.

CMOS Memory Settings changed in system BIOS are recorded and stored in CMOS (complementary metal oxide semiconductor) found in the motherboard chipset (south bridge or I/O controller hub). CMOS is low-powered memory powered by a small coin-sized lithium battery when the system is powered off. The memory holds the settings configured through BIOS. Part of the BIOS software routine that runs after the computer is turned on checks CMOS for information about what components are supposed to be installed.

CMOS Memory The information inside CMOS memory can be kept there for several years using a small coin-sized lithium battery. When the battery dies, all configuration information in CMOS is lost and must be re-entered. POST (power on self test) runs whenever the computer cold boots and it performs a hardware check on installed components. POST knows what hardware is supposed to be in the computer by obtaining the settings from CMOS.

CMOS Memory When working on a computer with a POST error code, ensure that the user or another technician (1) has not changed the configuration through the Setup program or (2) removed or installed any hardware without changing the Setup program or updating the operating system. Correct Setup information is crucial for proper PC operation.

BIOS Configuration Settings BIOS options vary according to manufacturer, but many options are similar. Most Setup programs have help that can be accessed from within the Setup program to explain the purpose of each option. Some motherboards have pins that, when jumpered together, remove the power-on password. Some motherboards distinguish between supervisor and user passwords. Another security option of some BIOSs is whether a password is needed every time the computer boots or only when someone tries to enter the Setup program.

BIOS Configuration Settings

You must save your changes whenever you make configuration changes. Incorrectly saving the changes is a common mistake made by a new technician. The options available when exiting BIOS depend on the model of BIOS being used

Motherboard Batteries The most common battery used today is a lithium battery about the size of a nickel. No battery lasts forever. Higher temperatures and powering devices that use batteries to power up and power down shorten a battery lifespan. Computer motherboard batteries last 3 to 8 years. Today, batteries last longer and people replace their computers more frequently; therefore, replacing batteries is not the issue it once was. When batteries fail, several options are available to the technician, depending on which type of battery is installed.

Motherboard Batteries