Introduction to DOS

Before we take a look at the DOS operating system in particular, let's consider what computing is all about. A computer is a tool to accomplish a particular task, such as producing a letter or report, calculating a formula, or communicating with a colleague. Consider the office in which you work. There is likely to be a workspace (desk), storage space (filing cabinets, drawers, etc.), and tools (pencils, pens, rulers, calculators, etc.). The layout of the room and the laws of physics (thank you, Newton) dictate how we can accomplish tasks within this office. If we want to work on a file, we must go to a drawer, pull on the drawer to open it, open the folder where the document is, grab the document, go to the desk...you get the idea.

On a computer, how you work is defined not by the laws of physics, but by the rules dictated by your computer's hardware and software. The software aspect of those rules is what we call an operating system. So in effect, the programmer (actually a series of teams of many programmers and designers) has created a new environment for working. In order to to do something in that environment, you must follow the rules of this new environment. In the physical world, we must follow Newton's laws in order to accomplish any task. Likewise on a computer, we must follow the programmer's laws; the only difference is that Newton did not decide what these rules would be!

The basic functions of an operating system are as follows:

• File management--analogous to the file cabinet and its use
• Working with the Files--analogous to picking up and preparing to use a calculator or some other tool
• Configuration of your working environment--analogous to shifting your desk around to suit you better

Many of you may be familiar with a particular application (e.g., WordPerfect 5.1). The description of an operating system may seem similar to what WordPerfect or any application provides: You have to follow its rules in order to do anything in that application. That is definitely true; but when the programmers of WordPerfect developed WordPerfect, they had to conform to the rules of DOS. To extend our analogy, WordPerfect is much like a sport. The rules of baseball are laid out and must be followed in order to succeed in the game, but those constructing the rules of baseball had very much in mind the laws of physics (whether they were conscious of it or not). Likewise WordPerfect must follow the rules of DOS in order to function.