Like data structure and algorithms
Os
Database systems
A few days ago, I just rethink about the 3 traversing orders, pre order , in order, and post order of binary search tree. To find out what are the various different use cases. Does that helps to answer your question?
Each time when I am doing performance test of systems, I always have to go back to the understanding of OS and database fundamentals to know if there are things that I may have missed out that may help to gain more performance out of the current piece of software that is written.
It is not about re-reading, it is about revisiting to find out if there are fresh ideas and approaches to an old topic and how one may use these revisiting to branch out new thoughts into other areas that were not thought of in the same manner or setting. Going back to the fundamentals is the best way to cut thru the complexity that are introduced latter in technologies, instead of just keep on stacking on the complex systems that could already be way out of tangent.