Linux+: Hardware Part 04 - Motherboard Chips The previous Hardware articles covered major components of the system, but these components all require pathways to each other as well as other devices and components not discussed. The main conduit for all the devices and components is the motherboard. The motherboard is also referred to as system board or main board. There are a few important chips on the motherboard which are imperative to the PC operations. The first chip to discuss is the Read-Only Memory Basic Input/Output System (ROM BIOS). When a PC is first turned on, it needs instructions to tell it what to do to load the installed Operating System (OS). The ROM BIOS contains all of the instructions to perform basic diagnostics and load the OS. There are four basic ROM BIOS functions: BIOS or CMOS setup – configure boot and system settings BIOS Drivers – allows use of hardware before OS loads Power On Self Test (POST) – diagnostics Boostrap Loader – loads OS The settings of the BIOS allow configuration of the boot order of installed devices. The boot devices can be the hard disk, floppy disk, CD/DVD-ROM, network card, etc. Other settings such as the system clock can be modified in the BIOS settings. Enabling of a Plug and Play system can be modified in the BIOS. There is also a keyboard BIOS which controls the keyboard and allows the keyboard to be used before the OS is loaded, such as to change the Complementary Metal–Oxide–Semiconductor (CMOS) settings. Also, video BIOS exists to allow video to be used before the OS is loaded, such as entering the BIOS settings and making changes. During boot-up, pressing a special key, such as <F2> or some other key, allows entry into the BIOS settings which are stored in CMOS. Other BIOS chips exist in expansion cards such as Small Computer Systems Interface (SCSI) cards, etc. The POST performs a memory check, system bus check and other checks of the hardware to verify that the system is in running order. The POST cannot verify hardware settings or anything dealing with the OS. The last item the POST performs is to load the Master Boot Record (MBR) from the first available boot device set in the BIOS Settings. This final process is the Bootstrap Loader where control is passed to information from the MBR which should load the default OS. Sometimes the BIOS software becomes outdated or has a problem. Some BIOS chips can be ‘flashed’. To ‘flash’ a BIOS chip is to overwrite it with a newer version of software. NOTE: Unless the update will fix something that is a problem, it is usually best to leave the BIOS alone. If anything goes wrong with the flash, the system can become unusable. Remember that the BIOS update may provide support for newer hardware such as a newer and faster CPU. Usually, a boot disk of some sort is used, either a floppy disk or a CD/DVD. The system is booted from the boot disk and control is passed from the BIOS to the boot disk. Once this occurs, an application is loaded which will get access to the BIOS that will then load a data file from the boot disk. The data file is sent to the BIOS using special commands which overwrite the existing data. Once done, the system is rebooted and the new BIOS data is used. If a power failure should occur during the writing of the BIOS codes, the BIOS cannot be used when the system is rebooted since the write did not complete. The BIOS is unusable and the chip must be replaced with a new one. Chipsets Another main part of the motherboard are the chipsets. Each motherboard will be fitted with a specific chipset that controls the data flow between the processor, Random Access Memory (RAM) and other devices. Each chipset is specific to a motherboard type and processor type. The chipsets can also be split into two categories: fast (northbridge) and slow (southbridge). The faster throughput is required for the RAM and graphics from the Central Processing Unit (CPU). Slower throughput from the CPU goes through the southbridge chips to the network devices, expansion slots, Universal Serial Bus (USB), other integrated chipsets, etc. NOTE: Newer motherboards have integrated devices such as video, audio, networking, USB, etc. These various devices are integrated by their own chipsets rather than be included as an expansion card with the chips on it. Each OS has drivers to support the various chipsets. It is important to update the chipset drivers when possible, but some suggest not performing the updates in case it may cause more problems. These drivers are important to system stability and performance. If system crashes are occurring often or system performance is low, the problem may be the chipset drivers. It may be best to consult the website of the chipset manufacturer for the latest drivers available for your Linux system.