Computer Fundamentals | IT Training

LEARNING OBJECTIVE: To introduce you to Computer Fundamentals and the system used by computers

There is a fundamental system common to all computers

The purpose of this module is to introduce you to the basic workings of a computer and also to show you that it really doesn’t matter what that computer is, be it a desktop PC or iPhone, the system remains the same.  These are the computer fundamentals to understanding how to begin your journey into IT Repair.

Computers, whether a PC, a laptop or netbook, iPad or smart phone all have a common system.

Definition of SystemIT Training slide 00006 - input process output

The system can be described has having an input section, a processing section and finally some form of an output.

A typical computer system

In the image above we can see a demonstration of a typical computer system.

For a PC this would comprise of a number of parts such as a keyboard, mouse, hard disk, motherboard etc but in it’s most basic form we can describe this as having an INPUT part, a PROCESSing part and finally some form of OUTPUT.

The human body is another example of a system

IT Training slide 00004 Picture showing the INPUT Process and Output parts of a system

We compare this system of a computer to that of the human body and it’s nervous system and we can use this as an analogy to help you understand how it compares to a computer system.

This system can be described as you and I having our human senses such as sight and hearing.

These can be considered as an INPUT method.

It is the job of our brain to decipher these messages (PROCESS) and finally to take action on them if required to do so (MOVEMENT).

Typical example of a human input process output system

The computer system is the same as the human system

The computer system is no different.  We typically can take INPUT from a keyboard, a touch screen or a mouse and it is the turn of the brain, or the Central Processing Unit (CPU) of the computer to finally take action and provide an OUTPUT, this could be in the form of graphics on a monitor screen or a printer or audio ouput.

The computer system example



Random Access Memory

Our human brain is able to handle input from our many senses very efficiently, most of the time we don’t even have to consciously be aware of the process.




Coping with multiple input data at the same time

We also saw that if the human senses are overloaded then our brain has a coping mechanism which allows us to pass information to other parts of our body to deal with.  There are different parts of the brain that handle different senses and the processing of those senses.  The CPU in a computer handles it’s input in a similar way.

The parts of the computer system

For now don’t worry too much about these different parts, let’s stay focused on the bigger picture.  Our human brain copes quite well with multi-sensory overload, however the CPU does not cope as well and prefers to deal with tasks only when it is ready to so.

The CPU coping with one input at a time

In order to achieve this it temporarily passes data that it is not ready to deal with to a temporary location.  This location is called the memory, or the Random Access Memory (RAM).

Multiple input to the CPUThe CPU and RAM relationship

The data will sit in the RAM until the CPU is ready to deal with it, once passed to the CPU the data is wiped from the place in RAM it was stored, this is known as VOLATILE MEMORY.  There is a different type of memory as we shall shortly see called…you guess it NON VOLATILE MEMORY.

The Computer Motherboard

Sticking with our analogy of the human body for a minute we know that our brain does the majority of the processing work but we have other parts to the system that also are vital for our health and well being, our organs.  We have a series of nerves, veins and arteries in order for our body to make use of these organs and the computer again is no different.

The CPU and RAM

The CPU and the RAM sit on a piece of circuit board known as the ‘MOTHERBOARD‘.  Here’s a typical picture:

A typical computer motherboard

There are parts of a computer which you may have heard of before such as the ‘Hard Drive‘ and the ‘Graphics Card’.

Hard Disk Drive

The Hard Disk Drive (HDD) or Hard Drive as it is more commonly known simply stores data, similar to your own memory.  This data could be your computer programs and or your files.

Things you will find inside a computer case

These are all bits that attach to the motherboard in order to work.  Sometimes these parts are integrated into the Motherboard (such as built in graphics or audio) and sometimes they are inserted into the board.  When they are inserted they are put into slots, called ‘Expansion Slots‘.

Expansion slots examplePC Expansion cards

These parts that are attached to the Motherboard are usually called ‘ PERIPHERALS‘.

 Cables everywhere

It’s easy to look inside a computer and become confused as to what all of the cables do.  For now let’s assume that they connect these peripherals to the motherboard and we don’t need to know too much about them at this phase.

Cables inside a PC


Plugging things into the computer motherboard

Rear view of a motherboard


The picture above is a typical view of the back of a modern computer.  The sockets and holes you can see are all designed for peripherals such as a keyboard and mice and computer monitors to be plugged into.

The Computer Case

All of these peripherals and the Motherboard are typically contained within a computer case and you’ve probably seen quite a few yourself.  Manufacturers of computer components will tend to make their computers in a variety of sizes and shapes.  This is usually to meet a purpose of the computer, one example being that the computer case can be attached to the back of a computer monitor, sometimes these solutions are purely aesthetic and other they serve a more practical purpose.  With a PC we generally find that regardless of it’s size and shape a case will usually be called a FLAT BED/DESKTOP or TOWER case.

A typical Tower computer case

A typical Tower computer case

A typical Desktop style computer case

A typical Desktop style computer case

Computers of differing sizes are described as having a ‘Form Factor’.  The laptop computer is a typical example as is the smart phone.  

What does form factor mean?


Putting it all together

If we add all of these parts together, the motherboard, the cables, the hard drive, the RAM we end up with something looking like this.

Inside a PC view 1 Inside a PC view 2

What is the connection between PC’s Laptops / Netbooks or tablet computers and smart phones?

The answer is the size and the shape.  If you think about it for a moment, they all still an input, a process and output.  A laptop is built to be portable and because of this it is smaller and has less power consumption requirements therefore can be ran on a battery, the same applies to a phone.  A touch screen device detects your finger or stylus and in turn transmits that information to a motherboard which in turn processing it and passes it as an output.

The main difference between a PC and laptop or tablet PC or smart phone

The way a PC communicates between the motherboard and it’s peripherals is through cables that can be a few millimeters in circumference. The same communication in a laptop is carries out by smaller cables that are usually flat rather than round and smaller devices such as iPads or smart phones have smaller cables again.

computer cables from a pc to a laptop smart phones communication cables




So we can see that a computer is a SYSTEM not too dissimilar to our nervous system.

A computer system comprises of  INPUT –  PROCESS  – OUTPUT stages.

Typically a computer will be made up of various components such as a Hard Disk Drive, RAM, Motherboard, cables, Power Supply, expansion cards and peripherals such as a keyboard and mouse.  The output will usually be from a monitor or printer.  These will be housed inside a case which will have a Form Factor.

It is the job of the CPU to run the mathematical commands to enable software applications to run and when it becomes overloaded it temporarily passes it to the RAM.  The CPU can receive it’s input from a number of places that we didn’t cover here in this section and it also passes some tasks to different sections of the motherboard or expansion slots to enable the overall computer to work.

All computers follow this system.  The only difference between different computer systems are their size, shape and the way they are connected.

Ok, next let’s look at the typical tools you need for computer repair…