CS61: Systems Programming and Machine Organization

CS 61 is the introductory systems programming class at Harvard, normally with around 200 students enrolled. Main topics include: C, C++, and assembly language programming, performance analysis and improvement strategies, memory management, caching, concurrency, threads, and synchronization. The class is taught by Professor Eddie Kohler with around 15-20 teaching fellows every year (of which I’m one!).

Here’s some of my favorite parts of the class:

My favorite section to teach: virtual memory!

I love page tables! It’s a unique data structure that allows us to map a huge address range with relatively few pages. Also the idea of virtual memory, while a simple one, is extremely powerful. I love blowing students’ minds with the idea of a virtaul and physical address space and that this conversion is actually done on hardware.

My favorite problem set: Shell!

While one of the most challenging of the assignments, it’s also so cool to build your own functioning shell. Also I think in terms of software design it has the most interesting design decisions in terms of how you want to structure and parse your commands. Also I think being able to fork off subshells and commands is such a cool concept and really allows for students to get a more concrete idea of process creation.