System Overview

The modern computer is a sophisticated machine that utilizes both hardware and software to accomplish a given task. While the term ‘hardware’ refers to the computer’s physical components, ‘software’ refers to the set of instructions that controls the hardware

All computer functions can be categorized as input, output, processing, or storage. Here are some examples of each:

For the purposes of our discussion, we’ll be primarily focusing on the hardware: the case and the components internal to it. Let’s begin with a hardware tour of the computer, beginning with the case, and then having a look inside it:

Case: computer cases come in a variety of styles, the main categories of which are the tower (mini-, mid-, full) and the desktop.

Power Supply: mounted on the inside corner of the case, the power supply supplies electricity to all of the devices inside the case. It can be identified by the multi-colored wire bundles protruding from it. The power supply poses a safety risk if opened; do not ever attempt to repair it. When it fails, replace it.

Motherboard: also known as the main board or system board, the motherboard is the largest and most powerful circuit board in the computer. It contains the central processing unit (CPU), expansion cards, memory, and other components.

Random Access Memory (RAM): these small circuit board modules, inserted into dedicated slots on the motherboard, are used to hold data and instructions as they are processed by the CPU.

Storage Devices: used for permanent data storage, they include the floppy drive, hard drive, and CD-ROM drive.

Expansion Cards: these circuit boards are plugged into slots on the motherboard and are used by the CPU to communicate with devices inside and outside of the case. Examples include the video card, sound card, network interface card, and so forth.

Cables: there are two types of cables inside your computer: data cables, which connect devices to one another (motherboard to the hard drive, for example), and power cables, which supply power. While power cords are small and round, data cables are usually flat and wide.

Cooling Fan: one of the most critical devices inside the computer is the cooling fan. The primary cooling fan is mounted to the power supply, and serves to keep the power supply from overheating. It also helps to expel warm air from inside the computer. Sometimes the addition of a case-mounted fan is necessary, and some devices, such as the CPU, have their own dedicated cooling fans to keep their operating temperature within an acceptable range.

Before removing the case cover, you’ll need to disconnect all cables and cords from the back of the computer. As you do this, make a note of the different types of connectors, plugs, and jacks that are integrated on the back of the case.

The jacks into which the keyboard, mouse, USB printer, and other devices are plugged are generally referred to as ‘ports’, since they provide the communications pathway between devices inside and outside of the computer.

Exercise caution when disconnecting and reconnecting devices to these ports. The plugs are designed to be inserted only one way, so never force them. If you look closely at the shape of both plug and jack, it will be easy to get them properly aligned.

Now that you have an idea about what is inside the case, take a few moments and have a look inside your own system.

A word about case covers. Case design can vary greatly from one manufacturer to another. Some case covers can be removed without any tools at all, while others may take just a single Phillips head screwdriver to remove. Some case covers simply swing open, while others need to be completely removed from the body of the case itself. When the case cover is removed, be sure to note how it fits onto the body of the case so that it is not misaligned when you reinstall it.

Don’t forget to unplug your computer first, and wear your antistatic wrist bracelet. Enjoy your tour!