When I was in undergrad I wanted to take Operating Systems 2 but it was only offered once/year and didn't match up with my free time. So I did an independent s

When I was in undergrad I wanted to take Operating Systems 2 but it was only offered once/year and didn't match up with my free time. So I did an independent study where my plan was to write a basic ethernet driver for Linux. I have never been as humbled by any sort of programming in my life. This was back in 2004 so the resources available online weren't nearly as good. I basically figured everything out by reading Intel's x86 documentation from start to finish. It took me a solid 3 weeks just to figure out how to start talking to the ethernet card. I spent days reading the same few pages in the manual over and over trying to understand how to get everything to fit together in assembly & C. After 9 weeks I was able to address & initialize the ethernet card after the OS booted. I never was able to send or receive any data after a solid 50 hours of work. Oh yeah, and I got a solid A for my work.