When teaching operating system concepts, there are basically two prevalent approaches. The first is abstract, and uses a virtual machine or some other user space tool to simulate an operating system environment with the aid of a high-level language. The second approach is concrete, and uses a microkernel or toy operating system that can run on actual hardware.

Having recently graduated from Georgia Tech, I believe that I’m not alone in saying that I come from the first camp of non-happy campers, though allow me to digress for just a moment.

The first half of our operating systems and architecture course, ECE3055, is admittedly excellent. The course provides a spectacular introduction to hardware and the MIPS architecture through the use of Hennessy and Patterson. And unlike many other colleges, we use a combination of VHDL and Altera tools to work with actual, honest-to-god, FPGA processors. Finally, the SPIM simulator is used to experiment with assembly level programming for the MIPS.

Sadly, these qualities don’t carry through to the second half of the semester. Here, Georgia Tech uses higher-level languages in an ill-conceived attempt to introduce students to genuine operating systems concepts such as file systems, memory allocation, and scheduling. In my opinion, that’s not the way to go. The use of these languages results in a very ethereal experience. And there’s just something distant and not quite satisfying about implementing a FAT virtual file system in a simulation environment on top of Java. In fact, I would go as far as to say that such a pedagogy actually turns away students who might have otherwise taken an interest in operating system design.

As a result, it’s difficult to make the connection between how such an implementation might translate in a real-world operating system. Disappointed, students like myself graduate with a very brittle and fragmented idea of what an operating system is all about.

This time, I’d like to do it right. The obvious choice appears to be MINIX. It’s a fully complete operating system with excellent documentation and a modular design that seems well suited for an undergraduate curriculum. But at the same time, maybe it’s just a little too much to absorb at once.

That’s where GeekOS comes in. I recently learned about this peculiar operating system and found that GeekOS follows the concrete methodology, with a tiny operating system kernel for x86 PCs. It’s also about as bare bones as you can get. The operating system is currently being used at the University of Maryland with great success. Additionally, David Hovemeyer has some useful information on hacking the GeekOS. I think that it might be worthwhile to look at GeekOS while simultaneously working with MINIX.