Yesterday the Linux operating system celebrated its 24th anniversary. Work on the operating system was started in April 1991 by Linus Torvalds and on August 25, 1991 he made a post on the comp.os.minix newsgroup on Usenet to detail his progress and to get help on technical issues. ARS Technica offers a nice write-up about how it all started:
Even though Linus had rushed out to buy his PC as soon as he had scraped together the money to do so, he was unable to plunge into the world of Unix immediately, since it took several months for the Minix floppy disks to turn up. So he passed the time as any real coder would—by playing games like Prince of Persia under MS-DOS. He was also exploring the architecture of the Intel 80386 chip. Linus described his early experiments thus:
I was testing the task-switching capabilities, so what I did was I just made two processes and made them write to the screen and had a timer that switched tasks. One process wrote A, the other wrote B, so I saw AAAA BBBB and so on. The first two months the amount of code I wrote was very small, because it was a lot of details, totally new CPU, I've never programmed Intel before.
Remarkably, that very simple task-switching program turned out to be the seed that grew into the Linux kernel...