Operating Systems and Networks (Basics): Concepts, Formulas, and Clear Examples
Combined OS+Network MCQs cover process vs thread, scheduling idea, memory terms, deadlock conditions, OSI/TCP layers, IP/DNS/HTTP basics, and simple subnet intuition—breadth over depth.
Link OS concepts to resource ownership (threads share address space; processes don’t). Network items often ask protocol-layer fit or port numbers at a recall level.
Process and thread
- Process: own address space; thread: lighter, shared memory within process.
- Context switch heavier for process than thread (same process).
Scheduling (concept)
- FCFS, SJF, round-robin with time quantum—know starvation vs fairness tradeoffs at descriptive level.
Deadlock four conditions
- Mutual exclusion, hold and wait, no preemption, circular wait—all needed for deadlock.
Memory terms
- Paging vs segmentation; virtual memory idea; thrashing = excessive paging.
Network layers
OSI 7 layers vs TCP/IP 4—map HTTP (application), TCP (transport), IP (network), Ethernet (link).
Example — Layer match
Router primarily operates at Network layer (IP); switch often at data link (MAC learning).
Common protocols
- DNS resolves name→IP; DHCP assigns IP; TCP reliable ordered; UDP lightweight.
- HTTP status: 404 not found, 500 server error (recognition level).
Step-by-step method for exam questions
- Classify question OS vs network vs hybrid.
- Recall definition table for the term used.
- For scenario MCQs, ask who owns what resource.
- For layer questions, trace data path top-down.
- Eliminate options with wrong layer or wrong direction (client/server).
- Pick standard textbook answer unless stem specifies trick.
Formula cheat sheet
| Situation | Formula | When to use |
|---|---|---|
| Shared code+data | Threads in process | Concurrency |
| Deadlock needs | All 4 conditions | Deadlock MCQ |
| Reliable stream | TCP | Transport choice |
| Name to IP | DNS | Application service |
| Logical addressing | IP / Network layer | Routing |
Frequently asked questions
Subnet math depth?
Basic CIDR and host count; not always tested.
Linux commands?
Occasional; focus on concept questions in generic aptitude.
Security (TLS)?
Know HTTPS = HTTP + TLS at high level.
Practice on this platform
Use 4 practice sets (10 MCQs, detailed solution after each answer) and 2 timed mocks (20 minutes) on this topic to convert formulas into speed and accuracy.