Core CS Fundamentals Roadmap

The three subjects every campus and off-campus interview asks about — operating systems, computer networks and OOP — in the order that makes them click.

9 milestones · ~114 hours total

1. 1

   How a computer runs your program

   ~12h

   CPU, memory hierarchy, stack vs heap, compilation vs interpretation, system calls. A mental model for everything after.

2. 2

   Processes, threads and scheduling

   ~18h

   Process vs thread, context switching, FCFS/SJF/Round Robin/priority scheduling, and how to compute waiting and turnaround times by hand.

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3. 3

   Synchronisation and deadlocks

   ~15h

   Race conditions, mutex, semaphore, monitor, the classic problems, the four deadlock conditions and how to prevent or avoid them.

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4. 4

   Memory management and virtual memory

   ~15h

   Paging, segmentation, page tables and TLB, page replacement (FIFO, LRU, Optimal), thrashing, Belady's anomaly.

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5. 5

   Networking fundamentals

   ~18h

   OSI and TCP/IP layers, IP addressing and subnetting, DNS, HTTP/HTTPS, ARP, NAT.

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6. 6

   Transport and reliability

   ~12h

   TCP vs UDP, the three-way handshake, flow and congestion control, ports and sockets.

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7. 7

   Object-oriented design

   ~15h

   Encapsulation, inheritance, polymorphism, abstraction, interfaces, SOLID, composition over inheritance — with examples in your main language.

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8. 8

   Interview round

   ~8h

   Explain each topic aloud in two minutes, solve three scheduling and three subnetting problems on paper, and revise the one-page notes you wrote.

9. 9

   Take a rated CS Fundamentals test

   ~1h

   Take a timed rated test to earn your first verified CS Fundamentals rating — the number recruiters see.

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