Introduction to Computers

This is the second part of an introductory lesson on computer "jargon" which is intended to simplify some of the more common computer terms. Remember though, that while it's important for you and your students to recognize these terms, you can use a computer without knowing everything that goes on "under the hood", just the way most of us drive a car without really knowing the basics of how it works. Don't agonize over the terminology, and don't be intimidated by it. If you did that with your car you'd end up taking the bus ever where.

Editor's Note: The first part of this article appeared in Volume 3, Issue # 3 of CONNECT. If you would like a copy, please contact us or visit us online at the addresses listed on page 16 of this issue.

Data and program instructions are stored in memory on memory chips. There are two main types of memory, read-only memory (ROM) or random access memory (RAM). ROM contains the basic operating instructions for the computer such as how to begin the startup programs. This information cannot be changed, or the computer will not function properly. It remains on the computer even when the power is off.

RAM is the information or set of instructions controlled by the user - it can be changed, but is only accessible while the computer is on. Data can be stored in the computer's hard disk or on removable diskettes (disks).

There are several types of disks available. The first diskettes which were used as storage were larger than those used today, and were softer and flexible. They were known as floppy disks. While this term is still used, most computer users now rely on the smaller hard plastic disks for saving or transporting data. Data can also be stored on compact disks (CDs). CDs have been available for computer use for several years, but up until recently, they were read-only CDs, which meant that they could only store information, as with CDs for music. Newer computers can now save information on CD, although this technology is more expensive than the commonly used diskettes.

Other types of information can be stored on cards, which may come with the computer or be installed later. These cards hold the circuits to manage a special function, such as managing sound, video or graphics. Cards can have thousands of tiny circuits installed on them.

In many locations computers are linked together in order to share information. Linking computers together creates a network. Each computer in a network is a terminal or workstation. A small network, such as in a classroom, would be a local area network (LAN). A larger network which could join several offices or locations is a wide area network (WAN). Computers on a network can have the same computer power as a stand-alone, which is just an ordinary PC, or it can be a dumb terminal, which means that it does not have any computing power. A dumb terminal receives all of its power from a server, or central computer. Each computer that is connected to a server is a client, so computers in a network are said to be in a client-server system. Note that a stand-alone computer is not part of a network - it stands alone.

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