"Don't use commercial software, and if you have to, at least use an illegal copy," was the most memorable line from the talk Richard Stallman gave in early April to a sparse group of diehard Harvard computer junkies.

Virtually unknown outside the computing community, Richard Stallman is one of the most bizarre, and certainly the most outspoken, member of it. He achieved fame by developing EMACS, the text editing program of choice for most computer users who work with machines larger than a Mac or PC.

Instead of selling EMACS, Stallman gives away the product of his years of effort--because he believes that all software should be free.

His logic is persuasive. Only one person can sit in a chair at any given time, so the concept of ownership is meaningful and necessary to the chair's use. In the same way, only one person can eat a sandwich. But a single piece of software can be used on one computer, or on 1,000 computers, without any harm to its "owner."

Why shouldn't I be able to share my software with my neighbor? Society continually reminds us that we should help other people, and sharing seems a virtually natural instinct. How am I helping anyone when I keep a neat word processor or a math package locked away on my computer for solely my personal use? If my neighbor wants my spreadsheet, I should certainly be free to give it to her--especially since it will not hurt me in the slightest.

But only if I long for the view behind bars. Software piracy is a federal crime. Magazine advertisements from the Software Publishers Association picture two hands locked in cuffs. The ads warn that "copying software could get you a free pair of these."

Maybe software piracy isn't all that bad. Some people consider it a passive means of resisting the status quo--overpriced software controlled by massive corporations.

Regardless, it would be difficult to find anyone at Harvard who owns a copy of every piece of software he or she uses, and who fully abides by every license restriction. Most people can't afford it, and the rest unwittingly violate license terms. For example, how many people actually place the software copyright notice on their one and only backup disk?

Richard Stallman's suggests using only "free" software to stay on the moral high ground, helping your neighbors without running afoul of the law. "Free," in this context, does not necessarily mean without charge; software users should certainly expect to pay for diskettes and manuals. But since this kind of software is free from copyright restrictions, owners can make hundreds of duplicates for friends who want copies.

Even Richard Stallman cannot abide by this high standard. To do anything more than beep when it is turned on, a computer needs an operating system. PCs require DOS, Macs use System 7, and workstations and mainframes use UNIX or VMS.

It takes dozens of programmers years to write an operating system. Such a system controls printing, file storage, screen display and keyboard input.

For now, even Stallman must use a commercial operating system because no "free" one exists. To change this, he is writing an improved version of UNIX from scratch--which he intends to give away.

After nearly a decade of work, Stallman is close to completing his operating system, called GNU. What he has written so far is considered among the best available. Parts of GNU are already standard in several types of computers. Some parts even lurk in the depths of HUSC, the Science Center computer system.

How can one man's operating system compete with those that took armies of programmers tens of millions of dollars to develop? Because "source code" is available for all free software programs.

Source code is the program as written in a computer language, usually C or Pascal. When you buy Microsoft Windows, you receive "object code" instead of source code. Computers understand object code, but the language is totally unreadable to humans. Source code can be translated into object code, but object code cannot be translated into source code.