Need to Know More?

Before you can do anything with a computer, you need to understand three basic terms: hardware, software, and IT.

• Hardware This term refers to all the physical parts of the computer: the beige box and all its contents, the mouse, the keyboard, the monitor, the speakers , and all the cables, to name a few. You can think of hardware as the parts of the computer that are still there when the computer is switched off. You'll learn more about different types of hardware later in this chapter.

• Software This term refers to the intangible instructions that tell the hardware what to do. When you switch on the computer and words and pictures appear on the screen, it's the software that dictates what those words and pictures will be and where they will be located. Software is split up into individual programs (for example, a word processing program or an email program) with distinct functions. You'll learn more about different types of software later in this chapter.

• Information Technology (IT) This term is the general term for all the hardware, software, and services associated with computer use. In addition to computers and the programs that they run, IT encompasses the networks that connect the computers and the people who make them work.

Types of Computers

So far, we've been speaking of "computers" as if they were a single thing. But in fact, there are many types of computers. To gain your ICDL, you need to recognize the main types of computers that you might encounter.

Distinguishing Computer Types

Understand and distinguish between mainframe computer, network computer, personal computer, laptop, personal digital assistant (PDA) in terms of capacity, speed, cost, and typical users.

The exam might ask you about five different types of computers:

• Mainframe computers are large computers that are typically used to run the operations of an entire department or company.

• Network computers are computers that fit on an individual desktop, but they might not have much storage capacity. Instead, they rely on devices elsewhere on the network to store information for them.

• Personal computers are computers that fit on or under an individual desktop and that store their own information. This type is probably the type of computer that you're most familiar with.

• Laptop computers are portable computers ranging in size from a briefcase to a small notepad. They typically fold up to protect their screens when not in use.

• Personal Digital Assistants ( PDAs ) are very small computers that fit in a shirt pocket. They have limited storage capacity and screen sizes.

Table 2.1 will help you compare these different types of computers.

Table 2.1. Comparing Computer Types

Unless you're specifically told otherwise , you can assume that questions on the ICDL exam are about using personal computers.

Main Parts of a Personal Computer

When you sit down with your computer, you should know what you're looking at. The exam will test your ability to recognize the different parts of a computer.

Knowing the Parts of Your Computer

Know the main parts of a personal computer, such as: central processing unit (CPU), hard disk, common input and output devices, types of memory. Understand the term peripheral device .

Let's take a little tour of the computer hardware that's probably on (or under) your desk. Think of this as basic orientation, just like learning that your car has tires, a trunk, and an engine.

The most obvious parts of the computer are usually the monitor, the mouse, and the keyboard. The monitor displays information to you and is an example of an output device . The keyboard and mouse let you send information to the computer and are examples of input devices . Together, input and output devices are examples of peripheral devices . A peripheral device is anything that you can unplug from the gray box. Other examples include printers, plotters , joysticks, and some modems.

You'll learn more about input devices and output devices later in this chapter.

Follow the cables back from the monitor, mouse, and keyboard: They all plug into the back of a single box that contains the bulk of the computer's hardware. Sometimes this box is informally called the CPU, which stands for central processing unit. More formally , though, the CPU is one part that's hidden inside the box. The CPU is the "brain" of the computer, where it carries out calculations. Figure 2.1 shows a typical modern CPU. CPUs are normally less than 2 inches square in size but are the most important and complex part of your computer.

Figure 2.1. A modern CPU, the brain of your computer.

Of course, the CPU isn't the only thing inside that big beige box! Other important components in the base unit of the computer include hard drives , memory, and option cards.

Your computer probably has at least one hard drive and might have more. The hard drive is a magnetic device that can permanently store information. When you save a file, it ends up on the hard drive, which preserves its information even when the power to the computer is turned off.

The hard drive isn't the only place in your computer where information can be stored. Computers also have two kinds of memory: random access memory (RAM) and read-only memory (ROM) . You'll learn more about these types of memory later in the chapter.

The base unit of the computer typically contains one or more option cards as well. If you look at the back of the computer, you'll find a series of "slots." Some of these might be empty, and some might have hardware in them. Typical option cards include video cards (which send information to your monitor), network cards, and modems (which communicate with other computers).

Computer Performance

Sometimes you'll hear people complaining that their computers are slow todayor, conversely, bragging that their new computers are fast. But what makes a computer fast or slow? You'll need to understand basic performance factors to effectively use computers.

Performance Factors

Know some of the factors that impact on a computer's performance such as: CPU speed, RAM size, the number of applications running.