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Level 1 · Digital Foundations · Course 1.1 Computer Fundamentals

Module 2: Operating Systems

Goal: understand what an operating system does, find your way around files and folders confidently, and know why permissions exist.

You'll need: your own computer. Lessons show Windows and Mac steps; Linux is similar to Mac.

Lessons

  1. 1What an operating system does15–25 minutes✓
  2. 2Windows, macOS and Linux15–25 minutes✓
  3. 3Files, folders and paths15–25 minutes✓
  4. 4Users and permissions15–25 minutes✓
  5. 5Task Manager and keeping the system healthy15–25 minutes✓

🛠️Module practice: organise and inspect

  1. Turn on file extensions and hidden-file display.
  2. Create a folder called Projects in your Documents folder, with a subfolder called my-first-site.
  3. Copy the full path of my-first-site and paste it somewhere. You'll use this folder in later modules.
  4. Check whether your everyday account is an administrator.
  5. Disable one unnecessary startup program and install pending updates.

✅Module check

Explain in a few sentences, in your own words:

What does an operating system do, and why does the "least privilege" rule matter?

Show a good answer

A good answer mentions: the OS manages the hardware for every program: it shares the CPU and memory, organises storage into files and folders, talks to devices and controls who can access what. Least privilege means giving each user or program only the access it needs, so a mistake or harmful program can only damage a small area instead of the whole system.

📝Module quiz

10 questions · 10 marks each · 100 marks in all · pass mark 70% · retry as often as you like ·

1. Why can't you run a Mac app on Windows just by copying the file across?

Why each option is right or wrong

  • “Windows blocks every file that is copied from another computer” (Incorrect): Windows lets you copy and open files from anywhere. The problem is the app's requests, not the copying.
  • “Mac apps only work while the computer is offline” (Incorrect): Internet access has nothing to do with it. Mac apps work online and offline on a Mac.
  • “The file is too large for Windows to open” (Incorrect): Size isn't the issue; Windows handles very large files. It simply can't understand a Mac app's instructions.
  • “Each app is built to ask one operating system for what it needs” is correct.

    Apps don't talk to the hardware directly. They ask the operating system to open files, draw windows and use the network, using that system's own 'language' of requests. A Mac app asks macOS; Windows doesn't understand those requests.

    • Different file formats too: Windows programs are .exe files; Mac apps are packaged differently, so Windows can't even start one.
    • The way round it: use a version built for Windows, a web app that runs in any browser, or a virtual machine running the other system.

📖 Revise: Lesson 1: What an operating system does

Question ID module-02-q1 · Report a mistake in this question
2. Two apps try to save to the same file at the same moment. What prevents chaos?

Why each option is right or wrong

  • “The internet provider, which queues the two saves in order” (Incorrect): Saving a file on your computer doesn't go through your internet provider at all.
  • “Each app checks the other app's memory before saving” (Incorrect): Apps can't see into each other's memory; the operating system keeps them apart. Coordination has to come from the OS.
  • “The CPU, which refuses to run two programs at the same time” (Incorrect): CPUs run many programs at once. Coordinating file access is the operating system's job.
  • “The operating system, which can lock the file while one writes” is correct.

    Managing access to files is one of the operating system's core jobs. It can give one program a lock on a file, so the other has to wait or is told the file is in use.

    • Why it matters: two programs writing at once could mix their changes and corrupt the file.
    • You've seen it: 'This file is open in another program' is the operating system protecting the file.

📖 Revise: Lesson 1: What an operating system does

Question ID module-02-q2 · Report a mistake in this question
3. Which operating system is a public web server most likely to run?

Why each option is right or wrong

  • “Windows 11 Home, because most people know it” (Incorrect): Windows 11 Home is a desktop edition for personal computers. Microsoft's server editions exist, but most web servers run Linux.
  • “macOS, because developers like Macs” (Incorrect): Many developers write code on Macs, but macOS is rarely used to run public servers.
  • “iOS, since it is very secure” (Incorrect): iOS is the iPhone and iPad system. It isn't designed or licensed to run web servers.
  • “Linux” is correct.

    Linux runs most of the world's web servers and cloud machines. It's free, stable, uses few resources, and is easy to control remotely with commands.

    • No licence cost: you can run hundreds of servers without paying per machine.
    • Built for remote work: servers usually have no screen, and Linux is fully manageable over SSH.
    • Ecosystem: web servers, databases and hosting tools are built and tested on Linux first.

📖 Revise: Lesson 2: Windows, macOS and Linux

Question ID module-02-q3 · Report a mistake in this question
4. A file is called invoice.pdf.exe. What is it really?

Why each option is right or wrong

  • “A PDF invoice that has been safely compressed” (Incorrect): Compressed files end in .zip or similar. .exe means a program, whatever comes before it.
  • “A backup copy of a PDF, kept in case the first one breaks” (Incorrect): Backups keep their original extension or add something like .bak. .exe is not a backup format.
  • “A PDF document, because .pdf appears in the name” (Incorrect): Only the last extension decides the type. The .pdf in the middle is there to fool you.
  • “A program disguised as a document” is correct.

    The real type of a file is its last extension. .exe means a Windows program, so opening it runs code on your computer. Putting .pdf before it is a common trick to make malware look like a document.

    • Turn on extensions: in Windows File Explorer, tick 'File name extensions' so tricks like this are visible.
    • What to do: don't open it; delete it, and if it came by email, warn the sender through another channel.

📖 Revise: Lesson 3: Files, folders and paths

Question ID module-02-q4 · Report a mistake in this question
5. What's the difference between C:\Projects\site and /home/asha/projects/site?

Why each option is right or wrong

  • “The second one is always on a USB stick plugged into the machine” (Incorrect): /home/asha is a user's home folder on Linux. USB drives appear under places like /media or /Volumes.
  • “One is a website address and the other is a file on disk” (Incorrect): Neither is a website address; web addresses start with https://. Both are folder paths.
  • “There's no difference at all; they are written the same way” (Incorrect): They're written very differently: drive letters and backslashes versus a root slash and forward slashes.
  • “The first is a Windows path; the second is a Linux or Mac path” is correct.

    Both describe the location of a folder. Windows starts paths with a drive letter and uses backslashes; Linux and macOS start from a single root / and use forward slashes.

    • Same idea, different format: both say 'go into these folders, one inside another'.
    • Why it matters: code that builds paths by hand often breaks when moved between systems. Path helpers in your language handle the difference.

📖 Revise: Lesson 3: Files, folders and paths

Question ID module-02-q5 · Report a mistake in this question
6. An AI coding tool asks permission to delete files anywhere on your computer. What's the least-privilege answer?

Why each option is right or wrong

  • “Give it your administrator password so it never has to ask again” (Incorrect): Admin rights give the tool power over the whole system. A single mistake could wreck your computer.
  • “Allow everything so that it can finish the work faster” (Incorrect): Speed isn't worth the risk. Broad access turns small mistakes into disasters.
  • “Turn off your antivirus first so it doesn't interfere” (Incorrect): Antivirus protects you. Turning it off removes protection without making the tool any safer.
  • “Allow it only inside your project folder, for what the task needs” is correct.

    Least privilege means giving a person or tool only the access its task needs, and no more. A coding task needs your project folder, not your photos, documents or system files.

    • Limits mistakes: if the tool misunderstands, it can only damage the project, which Git can restore.
    • Limits attacks: if the tool is tricked by malicious instructions, it still can't reach the rest of your computer.

📖 Revise: Lesson 4: Users and permissions

Question ID module-02-q6 · Report a mistake in this question
7. Why does installing software ask for an administrator password, but opening a document doesn't?

Why each option is right or wrong

  • “Administrators wrote the software, so they must approve it” (Incorrect): Software is written by developers, not by your computer's administrators. The prompt is about permission to change the system.
  • “The password makes the installation run more quickly” (Incorrect): Passwords add a check, not speed. The install runs at the same speed.
  • “Documents are always safe, so they never need any checks” (Incorrect): Documents can carry risks too, such as macros. They just don't change the system to open.
  • “Installing changes the system for everyone; opening only reads your file” is correct.

    Installing software writes to system folders, can add background services and affects every user of the computer. That needs higher permission. Opening your own document only reads a file you already own.

    • A safety check: the password prompt is a moment to ask 'do I trust this?' before something changes the whole system.
    • Malware relies on yes: much malware needs you to approve an install, so read the prompt before entering the password.

📖 Revise: Lesson 4: Users and permissions

Question ID module-02-q7 · Report a mistake in this question
8. A process you don't recognise is using 90% of the CPU. What should you do first?

Why each option is right or wrong

  • “End it immediately, because unknown processes are dangerous” (Incorrect): Some system processes are essential. Ending one blindly can crash the computer or corrupt an update.
  • “Unplug the computer from the wall to stop it at once” (Incorrect): Cutting power loses unsaved work and can damage files, and the process will just start again.
  • “Reinstall the operating system to clear everything out” (Incorrect): Far too drastic before you even know what the process is.
  • “Search its name online before ending it” is correct.

    An unfamiliar process might be a normal system task, such as an update or a search indexer, or it might be unwanted software. Looking it up tells you which, before you act.

    • If it's normal: let it finish, or reschedule it, rather than breaking an update halfway.
    • If it's suspicious: end it, then run a malware scan and check what starts automatically.
    • Where to look: Task Manager's 'Open file location' shows where the program lives, which is a strong clue.

📖 Revise: Lesson 5: Task Manager and keeping the system healthy

Question ID module-02-q8 · Report a mistake in this question
9. Your laptop takes three minutes to start. Where should you look first?

Why each option is right or wrong

  • “The amount of free space left on the desktop” (Incorrect): Desktop clutter barely matters. Programs launching at start-up are far more common culprits.
  • “The Wi-Fi speed, since start-up downloads Windows” (Incorrect): Windows is stored on your disk and loads from there. Wi-Fi speed doesn't affect how long start-up takes.
  • “The number of files saved in your Documents folder” (Incorrect): Documents just sit on the disk until you open them. Having many of them doesn't slow down start-up.
  • “The list of programs that start automatically” is correct.

    Many apps add themselves to start-up: chat apps, updaters, cloud sync. Each one competes for the disk and CPU while the computer is starting.

    • Where: Task Manager → Startup apps on Windows; Settings → General → Login Items on a Mac.
    • Then storage: if start-up is still slow, an old hard disk (HDD) is the next suspect; an SSD helps hugely.

📖 Revise: Lesson 5: Task Manager and keeping the system healthy

Question ID module-02-q9 · Report a mistake in this question
10. Is Android a completely separate operating system from Linux?

Why each option is right or wrong

  • “No, it is exactly the same as Ubuntu desktop Linux” (Incorrect): They share a kernel, but everything above it, apps and interface included, is different.
  • “It's a version of Windows that was adapted for phones” (Incorrect): Android has nothing to do with Windows. It was built by Google on the Linux kernel.
  • “Yes, it shares no code at all with Linux in any way” (Incorrect): It shares the most important piece: the Linux kernel.
  • “It's its own OS, built on the Linux kernel” is correct.

    The kernel is the core of an operating system: the part that manages memory, processes and hardware. Android uses the Linux kernel but adds its own system on top, so it isn't the same as desktop Linux.

    • Shared core, different experience: Android apps don't run on Ubuntu, and Ubuntu apps don't run on Android, even though both use a Linux kernel.
    • Why it matters: 'Linux' can mean just the kernel or a whole system like Ubuntu. Knowing the difference avoids confusion.

📖 Revise: Lesson 2: Windows, macOS and Linux

Question ID module-02-q10 · Report a mistake in this question

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