When Linus Torvalds completed an early version of Linux in 1991, he sent the following message to other programmers in an Internet user group: "Hello everybody out there using minix. I'm doing a (free) operating system (just a hobby, won't be big and professional like gnu) for 386(486)AT clones." Torvalds' message proved only partly correct. His hobby did produce a new operating system, but it turned out to be a very big and highly professional piece of software.