1. Application

1. Compiler, Data Type

2. DSA & Collections

3. Multi-thread, Concurrency

4. Memory Management (Heap, Static, Stack, Garbage Collector)

5. I/O Reader

2. Network

1. OSI Model

2. HTTP/HTTPS.

3. WebSocket/SSE.

4. DNS

5. TCP and UDP.

6. IP.

7. ARP.

3. OS

1. User mode and Kernel mode.

2. Syscall

3. Process and Thread.

4. Deadlock.

5. Memory Management.

6. Virtual Memory.

7. Paging mechanism.

8. File System.

4. DSA and Algorithm

1. Array/Linked List

2. HashSet

3. Heap

4. HashMap

5. Tree

6. Stack/Queue

7. Graph