Definitions

A computer system consists of two major elements: hardware and software. Computer hardware is the collection of all the parts you can physically touch. Computer software, on the other hand, is not something you can touch. Software is a set of instructions for a computer to perform specific operations. You need both hardware and software for a computer system to work.

Some hardware components are easy to recognize, such as the computer case, keyboard, and monitor. However, there are many different types of hardware components. In this lesson, you will learn how to recognize the different components and what they do.

Types of Computers

Before looking at the various components, it is useful to distinguish between two different types of computers: desktop computers and laptop computers. A desktop computer consists of a computer case and a separate monitor, keyboard, and mouse. As the name suggests, this type of computer is typically placed on a desk and is not very portable.

Typical desktop computer with a separate computer case, monitor, keyboard, and mouse

A laptop computer has the same components but integrated into a single, portable unit.

Typical laptop computer with integrated hardware components

While these two types of computers look quite different, they have the same general hardware components.

Hardware Components

Let's start with the computer case. This is the metal enclosure that contains many of the other hardware components. It comes in various shapes and sizes, but a typical tower model is between 15-25 inches high. Want to know what's inside? Okay, go get a screwdriver and let's open it up. Seriously, if you are really into computers, the best way to learn is to actually get hands-on. To save us some time, however, have a look at this desktop computer case. A computer enthusiast replaced the metal side panel with a transparent one, so we can have a look inside.

Although that photo looks pretty cool, it is a bit hard to recognize the individual components, especially with all the connecting wires running through it. This figure shows a more schematic version of a desktop computer, which makes it easier to point out the essential hardware components.

The various components of a computer case

The computer case contains a power supply unit (#6) to convert general-purpose electricity to direct current for the other components. The most critical component is the motherboard (#2), a plastic board on which several essential components are mounted. This includes the central processing unit, or CPU, (#3), the main memory (#4), and expansions slots (#5) for other hardware components. The internal hard disk drive (#8) serves as the mass storage device for data files and software applications. An optical disk drive (#7) makes it possible to read from and write CDs and DVDs. Other hardware components typically found inside the computer case (but not shown in the figure) are a sound card, a video card, and a cooling mechanism, such as a fan.

A computer system also needs input devices, such as a keyboard (#9) and a mouse (#10). To interact with a user, a computer system also needs a display device, such as a monitor (#1).