What does the kernel do?

Linux began in 1991, when Linus Torvalds started writing an operating system for Intel 386- and 486-based personal computers. He was inspired by the Minix operating system written by Andrew S. Tanenbaum four years earlier. Linux differed in many ways from Minix; the main differences being that it was a 32-bit virtual memory kernel and the code was open source, later released under the GPL v2 license. He announced it on 25th August, 1991, on the comp.os.minix newsgroup in a famous post that began with:

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. This has been brewing since April, and is starting to get ready. I'd like any feedback on things people like/dislike in minix, as my OS resembles it somewhat (same physical layout of the filesystem (due to practical reasons) among other things).

To be strictly accurate, Linus did not write an operating system, rather...