Uff, there's so much to go through there. It's turtles all the way down. Start with a course on computer architecture / digital design. Something that'll have

Uff, there's so much to go through there. It's turtles all the way down. Start with a course on computer architecture / digital design. Something that'll have you put together a simple 8 bit CPU. Move your way up with a course on operating systems - processes, swapping, cache invalidation, file systems, drivers. Then, maybe something on compilers? Or how to write your own interpreter. Finally, a good networking course is pretty important. Very little of this is theoretical compsci, but it's something that will get covered in a degree program. That said, knowing how to recognize what kind of class of algorithm we're looking at, and data structures all around.