I think the lecture content is really rich, and if you take this lecture and study the book again, it will be good knowledge. However, there are a few things that are regrettable. 1. It seems like you don't prepare for the class. You give incorrect information, point it out late, say things like "Oh, I don't know," and above all, you stutter. 2. From the perspective of someone studying operating systems starting with this lecture, it seems like you are teaching by targeting the students too much, saying "We did this last time, right?" It was very helpful, but I am leaving it because I feel regretful.