Assignment#1

Motherboard

A motherboard is the central or primary circuit board making up a complex electronic system, such as a modern computer. It is also known as a mainboard, baseboard, system board, or, on Apple computers, a logic board, and is sometimes abbreviated as mobo.[1]
Most after-market motherboards produced today are designed for so-called IBM-compatible computers, which hold over 96% of the personal computer market today.[2] Motherboards for IBM-compatible computers are specifically covered in the PC motherboard article.
The basic purpose of the motherboard, like a backplane, is to provide the electrical and logical connections by which the other components of the system communicate.
A typical desktop computer is built with the microprocessor, main memory, and other essential components on the motherboard. Other components such as external storage, controllers for video display and sound, and peripheral devices are typically attached to the motherboard via edge connectors and cables, although in modern computers it is increasingly common to integrate these "peripherals" into the motherboard.

Compnents and functionso

The 2004 K7VT4A Pro[3] motherboard by ASRock. The chipset on this board consists of northbridge and southbridge chips.
The motherboard of a typical desktop consists of a large PCB. It holds electronic components and interconnects, as well as physical connectors (sockets, slots, and headers) into which other computer components may be inserted or attached.
Most motherboards include, at a minimum:
sockets (or slots) in which one or more microprocessors (CPUs) are installed[4]
slots into which the system's main memory is installed (typically in the form of DIMM modules containing DRAM chips)
a chipset which forms an interface between the CPU's front-side bus, main memory, and peripheral buses
non-volatile memory chips (usually Flash ROM in modern motherboards) containing the system's firmware or BIOS
a clock generator which produces the system clock signal to synchronize the various components
slots for expansion cards (these interface to the system via the buses supported by the chipset)
power connectors and circuits, which receive electrical power from the computer power supply and distribute it to the CPU, chipset, main memory, and expansion cards.[5]

Bootstrapping using the BIOS

A computer motherboard is a piece of hardware: it is the physical circuits and interconnecting wires that forms the backbone of a computer. It has logic circuits which can be manipulated and controlled by the operator, the software program, and input peripherals. But in order to begin operating from a power-off state, a motherboard must be bootstrapped (or simply, booted) by an initial set of software instructions. Without this vital software, the motherboard is rendered useless.
Most modern motherboard designs use a BIOS, stored in a EEPROM chip soldered to the motherboard, to bootstrap the motherboard. (Socketed BIOS chips are widely used, also.) By booting the motherboard, the memory, circuitry, and peripherals are tested and configured. This process is known as a Power On Self Test or POST. Errors during POST result in POST error codes, ranging from simple audible beeps from the speaker to complex diagnostic messages displayed on the video monitor.
The BIOS often requires configuration settings to be stored on the motherboard. Since configuration settings must be easily edited, these settings are often stored in non-volatile RAM (NVRAM) rather than in some sort of read-only memory (ROM). When a user makes configuration changes or alters the date and time of the computer, this small NVRAM circuit stores the data. Typically, a small, long-lasting battery (e.g. a lithium coin cell CR2032) is used to keep the NVRAM "refreshed" for many years. Therefore, a failing battery on a motherboard will produce the symptoms of a computer that cannot determine the correct date and time, nor remember what hardware configuration the user has selected. The BIOS itself is unaffected by the status of the battery.
When IBM first introduced the PC in the 1980s, imitations were quite common. (The physical parts which made up the motherboard were trivial to acquire.) However, the imitations were never successful until the IBM ROM BIOS was legally copied.[10] To understand why copying the BIOS was an important step, consider that the BIOS contained vital instructions which interacted with peripherals. Without these software instructions in the BIOS, a PC would not function properly. (In most modern computer operating systems, the BIOS is bypassed for most hardware functions, but in the 1980s, the BIOS served many vital low-level functions.)
So when Compaq Computer Corp. spent US$1 million to clone the IBM BIOS using reverse engineering, they became an elite computer manufacturer of IBM PC Clones. Phoenix Technology soon matched their feat and began reselling BIOSes to other clone makers.[11] It has been noted that Microsoft was more than happy to license the operating system (DOS), and IBM was more than happy to sue companies[12] that violated the copyright of their BIOS. But by documenting and publicizing the reverse engineering of the BIOS, Compaq and Phoenix were legally competing with IBM using their own copyrighted BIOS