In Part 1 we built the foundation of our operating system using Rust, dove deep into murky low level waters and broke free from the shackles of stdlib while still keeping the compiler happy. Now we are going into the meat of it all - the entry point.
Feel free to clone the source code for part 2 from Github and follow along.
Prepare for Entry
When running programs on an operating system, there are a lot of things that are handled under the hood for us by the operating system. They are invisible to us and we take them for granted, we expect them to just work. In kernel space however, there are no training wheels, no invisible cogs turning in the background, everything is laid bare for us to see. Everything that works does so because we made it happen. It may sound overwhelming but it's this kind of foundational control that makes you truly appreciate how computers work at the lowest level.
At the lowest level, the way a CPU executes instructions is very different from the mental model that high level languages try to paint. If you are familiar with assembly then you already know this. Let's look at some core concepts you need to know in order to fully get into the vibe of low level program execution:
