Free, as in Beer

摘要

Ever since the birth of the free software movement, its defenders have struggled to explain just what "free software" is. If it is free, how do coders eat? And how do businesses that support the software - IBM, Hewlett-Packard -make any money from it? The standard answer has been a slogan: "Think free," the movement's founder, Richard Stallman puts it, "as in free speech, not free beer." You can charge whatever you want for free software. But what you can't do is lock up the knowledge that makes it run. Others must be allowed to learn from and tinker with it. No one is permitted a monopoly on the teaching that stands behind it.