"When I joined Bell Telephone Laboratories in 1976, my supervisor was Mike Pilla, who was one of the first Unix adopters for an internal operations support system. Mike liked to play practical jokes on his people, often as a learning experience. One day, Mike was trying to resolve a Unix problem, so he called Ken Thompson, the co-inventor of Unix. While he was on the phone in front of his terminal deep in conversation, one of the members of the group named John, used the 'write' command to write on his terminal: 'Panic; no cookie.' Mike then reported to Ken, 'Ken, I just got a panic, no cookie, what does this mean?' After a couple of minutes back and forth between Mike and Ken, John came into his room with a box of cookies and reported what he had done.
"Years later, in the mid '90s, I started on the UWIN (Unix for Windows) project. In the late '90s, there was a workshop in Seattle aimed at Unix users with an interest in Windows NT, which I attended. Since the audience was primarily Unix or Linux users, I knew many of the people. One talk that was presented by a speaker from Microsoft was an announcement and description of their Unix on Windows product.
"At one point, the speaker stated that their product comes with ksh, the KornShell. I knew that they were using MKS toolkit version of ksh, which is not completely compatible with the real ksh, and I raised my hand to point this out. He insisted that it, indeed, was the real ksh, and when I started going through the incompatibilities, he started arguing with me. After a few minutes and a few back and forth, someone in the audience blurted out, 'Don't you know who you are talking to?' The speaker turned red faced and the audience burst into laughter. It was a true Woody Allen moment from 'Annie Hall.'"
Andrew Tanenbaum tells how one comment changed everything:
"When Unix V6 was released, it became very popular at universities, and people began teaching it in courses. AT&T, for some incomprehensible reason, decided that having lots of students learn about Unix was a bad idea, so the V7 license said you couldn't teach it anymore. I needed an example for my operating systems course, so I decided to write a clone of Unix to teach from. This became Minix. But late in the development, it kept crashing, and I couldn't find the bug. It seemed completely random. I wrote an interpreter for the IBM PC, so I could run Minix in a reproducible environment. It ran perfectly on the interpreter, but still crashed on the hardware. (If I'd been smart, I could have turned the interpreter into something more like what is now VMware, but my focus was finding the bug).
"I was about to abandon the entire Minix project when one of my students mentioned that the Intel 088 gave interrupt 15 when it got too hot. I said there was nothing in the manual about this, but he said he heard this somewhere. So I changed the code to expect interrupt 15 and print out something when it happened. Sure enough, within an hour, I got the message, 'Hi. I am interrupt 15. You will never see this message. Have a nice day.' As a result of this off-hand comment from my student, Robbert van Renesse, Minix happened and became a phenomenon. One of the early users was Linus Torvalds, who said he bought an IBM PC just to run and study Minix. Eventually, he began modifying it and that led to Linux. Many of the early aspects of Linux were taken directly from Minix (file system, directory layout, etc.).