CS Fundamentals · INTERVIEW & OA PREP
OOP, OS, DBMS & Networks Basics
Core CS theory rounds are near-universal in Indian tech hiring. You don't need research depth — you need crisp, confident one-paragraph explanations of the concepts that come up again and again.
Key concepts
- OOP: encapsulation, inheritance, polymorphism, abstraction — with a real example each.
- OS: process vs thread, deadlock (and its four conditions), paging, scheduling.
- DBMS: normalization, ACID, indexing, joins, transactions.
- Networks: TCP vs UDP, what happens when you type a URL, HTTP vs HTTPS.
Questions that get asked
- Difference between a process and a thread.
- Explain the four conditions for a deadlock.
- What is database normalization and why does it matter?
- What are ACID properties?
- TCP vs UDP — when would you use each?
Tip
Prepare a 30-second and a 2-minute version of each concept — interviewers probe depth by asking follow-ups.
Common mistake
Reciting definitions without examples. 'Polymorphism is...' lands far better with a one-line code example.
Quick checks
Three tap-only questions to test your recall on this topic.
Keep going
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