Okay so I've been lurking here for a while and finally made an account because I wanted to share what actually worked for me. I failed the OS certification exam twice — once in November and again in February. Both times I thought I was ready, both times I walked out feeling like the floor dropped out from under me. The memory management and process scheduling sections absolutely wrecked me.
What finally clicked was ditching the textbook-first approach and starting with an OS practice test to figure out exactly where my gaps were. Sounds obvious in hindsight but I'd been reading chapters front to back without knowing what the exam actually emphasizes. I also found a solid OS exam study guide that broke down virtual memory and deadlock detection in plain language instead of academic jargon.
Third attempt I scored a 78, which cleared the passing threshold by a decent margin. Took me about 6 weeks of focused prep, roughly 90 minutes a day. Happy to share specific OS exam tips that helped if anyone's in the same boat I was.