Yes, totally normal. If you want to brush up on that knowledge it won't take much time either; maybe couple of weeks and you'll be able to recollect. The thing

Yes, totally normal. If you want to brush up on that knowledge it won't take much time either; maybe couple of weeks and you'll be able to recollect. The thing though is most of the thing we (at least I) learned are outdated by at least 10 years. So if you want to learn how things work out in the field I suggest reading about actual implementation. For instance this book is terrific about Linux OS [1], and this is a classic on concurrent programming [2], this one about MySQL [3] and so on. [1] https://www.amazon.com/Linux-Kernel-Development-Robert-Love/dp/8131758184 https://www.amazon.com/Linux-Kernel-Development-Robert-Love/... [2] https://www.amazon.com/Art-Multiprocessor-Programming-Maurice-Herlihy/dp/0124159508 https://www.amazon.com/Art-Multiprocessor-Programming-Mauric... [3] https://www.amazon.in/Understanding-MySQL-Internals-Discovering-Improving-ebook/dp/B0043EWUIO https://www.amazon.in/Understanding-MySQL-Internals-Discover...