Nobody is telling you to spend all your free time on CS101 for months. It shouldn't take months. Go back, pick up an OS textbook and read a few pages without all that academic pressure. I bet you'll appreciate the writing a little more.
You totally missed the point, may be this makes sense for a few people. But a whole majority of people don't find it a very good use of their time to gain knowledge just for its own sake.
If I were writing a OS, I would bury myself in all the OS books in the world, and work atrocious hours to build one. But if you are asking me to do it, because I have to face an hour of interview 6 months from now, I find this a pointless exercise.
