Ken is definitely a top-notch programmer. A top-notch programmer can do a LOT given 3 weeks of focus time. I remember his wife took the kids to England so he was free to do whatever he wanted. And he definitely had a lot of experience before writing what was first version UNIX.

Every programmer that has a project in mind should try this: Put away 3 weeks of focus time in a cabin, away from work and family, gather every book or document you need and cut off the Internet. Use a dumb phone if you can live with it. See how far you can go. Just make sure it is something that you already put a lot of thoughts and a bit of code into it.

After thinking more thoroughly about the idea, I believe low level projects that rely on as few external libraries as possible are the best ones to try the idea out. If your project relies on piles of 3rd party libraries, you are stuck if you have an issue but without the Internet to help you figure it out. Ken picked the right project too.