1. Computer Architecture 2. Operating Systems 3. Database Concepts 4. Computer Networks 5. Theory of Computation 6. Compiler Design 7. Linear Algebra 8. Statistics and Probability
Also, how does one remember the breadth and depth of CS topics? It feels like I forget what I learn after a few days/weeks and have to start from scratch.
Most likely I found it here on HN but I can't remember what thread.
I remember a lot of things mostly because I have done them so many times... Most things I just keep at the back of my head, I know where to look for something when I need it. What to google, where to look.