Function of computer hardware components.

Motherboard.
The motherboard is perhaps the most important hardware component located inside the computer systems casing. The reason is simple: The motherboard is where other key components are plugged in or connected e.g. monitor. The motherboard chipset is the combination of the northbridge and southbridge processors. Some chipsets are more popular with system builders because they are more reliable or perform quicker in benchmarked tests. A southbridge may not be present on all motherboards, some manufacturers prefer to delegate its role to seperate subprocessors.

BIOS.

The basic input output system is a small collection of programs that are stored in a read only format (ROM) here are a few examples of this: Programmable read only memory (PROM), erasable programmable read only memory (EPROM) or most commonly these days flash memory. Existing as a small chip, the BIOS is fitted onto the motherboard of a typical PC system. On a typical PC system, the BIOS chip contains all codes required to control the keyboard, display, disk drives and other critical functions. It can also monitor hardware to prevent any damage occuring to the hardware.

In addition, it has a BIOS set up program which lets the user configure the basic operations on the hardware. Another function of the BIOS is the power on the self test procedure that checks to see that all connected peripherals and components are functioning correctly.

Malfunctioning devices are often reported via short on screen messages or, commonly as a series of beep codes. Unfortunately beep codes tend to be specific to different BIOS manufacturers.

CMOS.
Complementary metal oxide semiconductors is a special type of battery-backed memory that stores the settings made by the BIOS set up program. If problems occur the settings may be reset by either removing the 3v lithium battery or by using the clear CMOS jumper that is usually located near to the battery or BIOS chip on the motherboard.

CPU.
In simple terms the central processing unit is the brain of the computer system. In reality the processor is alot more complex, sitting at the heart of the computer system, the processors job is to process data and instructions. The instructions are specific to the CPU it is called "the machine code". Machine code from one type of processor will not traditionally work on another unless they belong to the same family (they are then said to be code compatible). For many years Intel have developed an x86 family of processors including the 486, pentium, pentium 2, pentium 3, pentium 4 etc. These are all backwardly compatible with each other. Other manufacturers such as AMD created processors which were machine code compatible, these include the k5, k6, athlon, duron and sempron etc.

Processor speeds.
Processor speed is measured in megahertz (MHz) or gigahertz (GHz). The speed is actually the clock frequency of a processor, a faster processor will execute a programs instructions quicker, this will not work if the motherboard cannot run at the same clock speed.

Processor bus.
A processor bus can also be called a front side bus (FSB).
It is the bidirectional link between the motherboard and the processor itself. Like the processor it operates at a certain clock speed, this is usually measured in MHz.
Multiplier: A bus multiplier is a value used to calculate the maximum processor speed.
The general equation for working this out is:
Maximum processor speed = processor bus speed  x  maximum multiplier e.g. 
          1992 GHz                =            166MHz        x            12

Power supply unit.

A power supply unit (PSU) can convert the incoming 110V or 220V alternative current (AC) into various direct currents, this makes voltages suitable for the computers internal components so that you don't get harmed e.g. electric/static shock. A power supply's output is measured in watts, 400 watts was a typical power output in 2007. Most PSUs come already fitted inside the computer systems casing, however they may have been purchased separately when a replacement is needed. As they contsin lethal voltages, they should never under any circumstances be dismantled even after the power has been removed.

Connectors.

 Laptop connector.

Most portable computers have power supplies that provide 25 to 200 watts. In portable computers (such as laptops) there is usually an external power supply (sometimes referred to as a "power brick" due to its similarity, in size, shape and weight, to a real brick) which converts AC power to one DC voltage (most commonly 19 V), and further DC-DC conversion (Direct Current) occurs within the laptop to supply the various DC voltages required by the other components of the portable computer.

Desktop connectors.

Power Cable

A power cable runs externally from the PSU case and is connected to the mains using a three-pin plug. The cable connects to the PSU using a standard three-point connector. Some PSUs also have a pass-through connector, which allows them to feed mains power to other external components, such as monitors.

Drive Connectors.

PSUs usually have at least 5 power connectors for delivering power to internal components not fixed to the motherboard. Typically, this includes hard disk drives and CD/DVD devices. Different cable and connector types are needed to connect PSUs to different devices, such as IDE-based drives and SATA-based drives. If more power connections are required, the number can be increased by using splitters which create 2 connections from one.

Motherboard Connectors.

Power is sent from the PSU to the motherboard via specific wired connections. The CPU, expansion slots, memory and other components all need to receive the correct voltage from the PSU, there are locations on the motherboard designed to receive the PSU connections. Connections to the motherboard must be made accurately, since the wrong connections can result in damage to the computer.

RAM.

RAM is a type of memory used to store the operating system, programs being run and most importantly the data being processed. It is also faster than ROM, which is why the BIOS is often shadowed (copied) to RAM and executed from there. Another important thing to remember is that RAM is volatile, this means that the contents of RAM are completely lost when electrical power is removed, when looking into RAM it is useful to think about the memory size. In computing, memory has traditionally been grouped into collections of bits and bytes, you can also encounter larger amounts like kilobytes, megabytes, gigabytes and terabytes.

Hard drives.

A hard drives technology has embraced three standards. The oldest technology, advanced technology attachment (ATA) - connects IDE hard drives to a motherboard via 40- or 80- wire cables, the most recent ATA standard is ATA133.

Another hard drive technology is small computer system interface (SCSI) and has been favoured for server systems, having a combination of large capacity, fast rotation speeds and superior transfer rates. 

A more recent development, serial ATA (SATA) has been introduced and is quickly becomingpopular with hard drive manufacturers. 

Hard drives have many uses, some uses are:

1. Everything gets saved to the hard drive.
2. The hard drive holds the installed programs, data files, operating system files and archives found on the computer.
3. A hard drive makes a modern computer function and work properly.

Optical backing storage.

Optical backing storage uses laser-generated light instead of magnetic fields to 'read' and 'write' data. In comparison it is typically slower than magnetic mechanisms. The most common  optical storage devices are CD's and DVD's, they are physically similar and both have the same diameter of 120mm.

The majority of optical devices use removable media, you are certainly familiar with CD-Digital Audio (CD-DA) discs used for music and DVD - ROM discs that hold popular films, television series and concerts. CD - ROM discs are manufactured with data literally 'pressed' into them in the form of pits (small indentations) and lands (the flat area between the pits). These pits and lands exist in a long spiral starting at the centre of the disc and working to the outer edge.

Optical storage have many uses, some uses are:

1. Optical CD-ROMs became the preffered method of software distribution.
2. DVD's allow much more data to be stored on a single disk.
3. Optical drives have now replaced tapes and CD-ROMs.

Pen drives.

Pen drives were introduced in the late 90's, pen drives are an increasingly popular form of backing storage due to their portability, ease of use and value for money. Based on NAND - flash architecture developed by Toshiba in the late 80's, a pen drive consists of a male USB connector, a printed circuit board containing flash memory and clock crystal (for synchronisation). These components are typically housed in toughened plastic packing or metal which include a removable cap to protect the sensitive contents from electro static discharge.

Flash memory cards.

There are many different formats of flash memory cards currently available and in use. Most flash cards use the name NAND - flash architecture as pen drives do but come in a number of different form factors. Common varieties include:

• Compact flash, created by SanDisk in 1994.
• MultiMediaCard created by SanDisk and Siemens in 1997.
• Memory stick created by Sony in 1998 varieties include Pro, Duo and micro.
• xD - Picture Card created by Olympus and Fujifilm in 2002.

It is becoming increasingly common for computer systems to have front bezels which contain multi-format card-reading slots. External card readers are also available and relatively inexpensive, they connect to the system via a standard USB port.

Performance factors for backing storage mainly concern three ain aspects:

1. Capacity - how much data it can store.
2. Data access time - how quickly specific data can be found.
3. Data transfer rate - how quickly data moves from the device into the computer.

Flash memory cards have many uses, some uses are:

1. Digital/video cameras, PDAs, industrial computers, portable computers and adaptors all use them in one way or another.
2. Can be used as a storage device to transport data to other devices.
3. Flash memory replaced floppy drives and film.

Expansion cards.

An expansion card is an electronic circuit board that adds more functionality to a desktop computer. Expansion cards are installed into the expansion slot of a computer motherboard. They enhance the computer’s ability to perform additional functions not offered by the motherboard. Video cards and sound cards are common examples of PC expansion cards. A new video card added will enhance the three dimensional graphics processing power of a computer while a new sound card may improve a computer’s audio input.

Laptops do not use standard cards due to their small form factor. A laptop expansion card can be in the form of a removable PCMCIA card that offers additional functionalities to it.

Most cards are inserted in PCI slots. PCI slots or “Peripheral Component Interconnect” slots are integrated circuits fitted onto the motherboard. One edge of the expansion card holding the contacts or keys is inserted into the PCI slot. This establishes an electrical contact between the motherboard and the card’s integrated circuits.

Electrostatic discharge.

Electrostatic discharge, ESD is one of the few things an individual can do to damage or destroy a computer or  its hardware components. Much like the shock you receive when rubbing your feet on the carpet abd touching something metal, ESD can occur when working in your computer and will cause components you touch  to no longer work properly. ESD can occur without the user feeling a shock and will only occur while working on the inside of the computer.

How to prevent ESD.

To prevent static shock you can use equipment like:

1. Antistatic workbench mat.
2. Antistatic wrist strap.
3. Antistatic bag.
4. crocodile clips.
5. reduce clothing to minimum (this means less friction).

After attempting an installation or upgrade and you find out your computer has stopped working correctly, you should remove the component you installed and find another one that is compatible with your computer. But if it does work when you reboot your computer then you can keep using it as usual as there shouldn't be a problem with the system.