Around 1980, Xerox Corporation donated a 9700 laser printer to the mit-ai-lab. The printer was a high-end machine, and like most Xerox hardware, its software was proprietary. stallman wanted to modify the printer's software to add features that would improve lab productivity — specifically, a notification system to alert users when print jobs completed or when the printer jammed, functionality he had previously implemented on an older printer by modifying its driver source.
Stallman requested the source code from Xerox. Xerox declined. This refusal was not merely an inconvenience; it meant that stallman and the other AI Lab programmers had lost the ability to adapt their tools to their needs. The printer could malfunction and no one could fix the software problem; it could be missing useful features and no one could add them. The hacker culture of the mit-ai-lab-hacker-culture-1971-1984 era — described in hackers-levy — was built on exactly this kind of collaborative modification and improvement. The Xerox refusal was an early encounter with the proprietary model's practical consequences.
The incident had a second, equally formative component. stallman learned that a researcher at Carnegie Mellon University had obtained a copy of the Xerox printer software. When Stallman sought the source code from that researcher, the researcher refused — explaining that he had signed a non-disclosure agreement. This refusal by a fellow programmer, under obligation of an NDA, demonstrated that the problem was not merely corporate policy but a social and legal structure that could compel people to refuse help they might otherwise provide. The NDA transformed a willing colleague into someone obligated to maintain secrecy.
Stallman later described this experience as pivotal to his philosophical development. It illustrated that proprietary software creates a class of people who cannot share knowledge, who are constrained from the cooperative practices that had made the MIT hacker community productive. The ethical claim at the center of stallman's later work — that software developers who refuse to share source code are harming their users and their community — was forged in direct response to this experience.
The Xerox printer incident is recounted in free-as-in-freedom-williams and in stallman's own account in the-gnu-project-essay. It is positioned in both accounts as the moment that transformed personal frustration into philosophical conviction, ultimately leading to the announcement-of-gnu-project in 1983, the founding-of-fsf in 1985, the gpl-v1, and the entire architecture of copyleft.
The incident is also the origin story of hacker-ethic-mit encountering the proprietary software regime that would define the conflict of the next four decades. The free-software-definition and the four-freedoms are in part a direct response to what the Xerox printer made visible: that software secrecy is not a natural condition but a choice with consequences for everyone who uses the software.