An operating systems course and a compiler course are what would complete your fundamentals. I have no idea how good the OCW courses are on these subjects (or i

An operating systems course and a compiler course are what would complete your fundamentals. I have no idea how good the OCW courses are on these subjects (or if they even exist at all), but if they sound something like "build your own OS/compiler" then you're probably on the right track. Bear in mind these two courses will contribute minimally (if at all) to your startup but its a nice to have a basic knowledge of how these two things work.