✅ Quiz 13 — Operating Systems & Networks
Answer first, then peek. If a question stumps you, the section heading it echoes is the place to re-read.
1. Your phone appears to run 50 things at once on a handful of processor cores. What’s the trick, and what is it called?
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The OS switches each core between programs thousands of times per second — one chef tending fifty pans so quickly that every pan seems to have a private chef. The trick is called scheduling.2. Why doesn’t one crashed app take the whole phone down with it?
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Every app runs in its own process — a sealed workspace with its own walled-off memory. The crash cannot reach other processes, and the OS can evict the broken one alone (that's what force quit is).3. Your computer gets slow and the disk churns whenever too many programs are open. Using the hotel analogy, what’s happening?
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The guests have outnumbered the rooms: RAM is full, so the OS moves some processes' memory to swap — overflow storage in the basement (the disk). Every retrieval from the basement is far slower than from a room, which is the sluggishness you feel.4. A flashlight app asks to access your contacts. Why does it have to ask — and what should you think?
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Apps can't touch hardware or data directly; everything goes through the OS, which checks its permission list first — the manager checking the guest list. And you should think like the manager: a flashlight has no business reading contacts, so the answer is no.5. What is the kernel, in one sentence?
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The innermost core of the operating system — the manager's inner office — with total authority over the processor, memory, and hardware.6. Your laptop’s address is 192.168.1.23 and so is your neighbor’s laptop’s. Why is that not a problem, and what does the router do so the internet can still reply to each of you correctly?
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Local IPs are apartment numbers — meaningful only inside each building, so two homes can reuse them. Each home shares one public IP (the street address). The router performs NAT: it rewrites outgoing traffic to use the public address and keeps a ledger of which conversation belongs to which device, so replies get sorted back to the right apartment.7. What is a port? Which port does secure web traffic (HTTPS) use?
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A numbered door on one address, so traffic reaches the right *program* on a device — not only the right device. Secure web traffic knocks on door 443.8. Your friend says “I got a VPN, so now nobody can see what I do online.” What’s accurate in that, and what’s the honest correction?
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Accurate: their internet provider (and anyone on the local WiFi) now sees only an encrypted tunnel, not the sites they visit — genuinely useful on untrusted networks. Correction: the VPN company's servers unwrap that tunnel to forward the traffic, so the VPN company can see what the ISP no longer can. A VPN moves your trust to a different party; it isn't invisibility.9. Latency vs. bandwidth: define each with the courier analogy, and explain why video calls can stutter on a connection where huge downloads run perfectly.
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Latency is the bike courier — how quickly one small message makes the round trip (milliseconds). Bandwidth is the truck — how much data flows per second (Mbps). Downloads are truck work: massive cargo, no urgency per box. Live calls are courier work: tiny packets that must arrive right now, in rhythm — every late courier is a frozen frame. A connection can have a great truck and unreliable couriers at once.10. “The WiFi is down!” Give the four-step checklist for finding which manager actually failed.
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(1) Do other apps/sites work? → one service's backend is down, not your network. (2) Do other devices in the house work? → if only one device fails, restart that device (its OS gets a clean shift). (3) Everything failing? → restart the router (the mailroom gets a clean shift). (4) Still down? → the problem is your internet provider's line, beyond your walls — call them, with your evidence.11. What is a driver, and why does “update the driver” so often fix a printer?
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A small program that translates between the OS and one specific piece of hardware — an interpreter for that gadget's dialect. Printers misbehave when the interpreter mistranslates; an updated driver is an interpreter with corrected vocabulary.12. 🗣️ Explain it to a friend. A family member asks: “Why does restarting the router fix the internet so often?” Explain in under a minute, using the managers from this module.