A bit of context for non-Princeton readers (commenting with a throwaway because I don't want to dox myself). You can take the CS major as either a Bachelor's o

A bit of context for non-Princeton readers (commenting with a throwaway because I don't want to dox myself). You can take the CS major as either a Bachelor's or an Engineering degree. Princeton requires all Bachelor's students to do two semesters of "independent work" their junior year, plus a thesis senior years. Engineering students have to do one semester of independent work, but they have to take additional courses and have more specific requirements. (The CS BSE degree is currently unique in not requiring a thesis.) For many departments, junior independent work is a 20ish page research paper you write over the course of the semester either as part of a seminar or one-on-one with an advisor, so the CS independent work is intended to be roughly equivalent in terms of rigor. It's my understanding that most CS students work on a significant piece of software with a writeup at the end of the semester—often (but not always) in a semester on a single topic (eg computer vision, digital audio, etc) junior fall, and one-on-one with an advisor (or in a lab) junior spring. BSE students will often do their one semester of independent work senior year, in either form. It's often pretty daunting staring at these requirements—and a lot of the onus is on you, the student, to figure out what you want to do and initiate it—so this advice seems to me to be aimed at students starting to plan their independent work. Don't take this as gospel—I'm actually not a CS major, somewhat ironically, though I have many friends who are. Just hope this helps to contextualize Kernighan's advice.