Module 1: How Computers Work

Why each option is right or wrong

• “The laptop's SSD” (Incorrect): The SSD is hardware: the physical part that stores data. The photo lives on it, but the drive itself is not data.
• “The gallery app that shows your photos” (Incorrect): The gallery app is software: a program of instructions that opens and shows photos. It works on data, but it isn't data.
• “Windows” (Incorrect): Windows is software too, an operating system that manages the hardware and runs other programs.
• “A photo of your family” is correct.

  Data is information: the content that programs create, store and show. A family photo is a file of colour values for millions of tiny dots (pixels). It doesn't do anything by itself; a program has to open it.

  • The test: if you can touch it, it's hardware. If it gives the computer instructions, it's software. If it's the content being worked on, it's data.
  • Why it matters: backups exist mainly to protect data. Hardware can be bought again and software reinstalled, but a lost family photo is gone for good.

📖 Revise: Lesson 1: Hardware and Software

Why each option is right or wrong

• “The CPU deleted it when the power failed” (Incorrect): The CPU processes instructions; it doesn't decide to delete files. With no power it simply stops.
• “Storage is wiped clean whenever the power cuts out suddenly” (Incorrect): Storage (SSD or hard disk) is built to keep data without power. That's why saved files survive.
• “The operating system was uninstalled by the shock” (Incorrect): A power cut doesn't uninstall programs. Usually the computer starts again normally and only unsaved work in RAM is lost. Occasionally a cut in the middle of saving or updating can damage that one file or update, which is why autosave, backups and a UPS (a battery that keeps the computer running for a few minutes) help.
• “It was only in RAM, which empties when the power goes” is correct.

  While you type, the document you're working on is held in RAM, the computer's fast working memory. RAM needs constant power to hold anything, so when the power cuts, everything in it vanishes.

  • Saving copies the work to storage: pressing Save writes it to the SSD or hard disk, which keeps data with no power at all. (A cut in the very moment of saving can still damage that file, which is one reason backups matter.)
  • Why autosave helps: many apps save to storage every few minutes, so a power cut only loses the last few minutes, not the whole session.

📖 Revise: Lesson 3: RAM, the working memory

Why each option is right or wrong

• “The disk is too full to keep the pages loaded properly” (Incorrect): The question says there is plenty of free disk space, so a full disk is ruled out.
• “The CPU is too old to run modern websites” (Incorrect): An older CPU makes every page a bit slower, but it wouldn't explain slowness that grows with each extra tab. That pattern points to memory.
• “The internet connection is too fast for it” (Incorrect): A fast connection doesn't slow a computer down. Slowness that grows with open tabs points at memory, not the network.
• “RAM is full, so it is swapping to slower storage” is correct.

  Each open tab uses RAM. When RAM runs out, the operating system moves parts of memory out to storage (swapping) and back again when needed. Storage is far slower than RAM, so everything feels sluggish.

  • Free disk space doesn't help: disk space and RAM are different things. A big empty disk can't replace working memory.
  • The fix: close tabs you don't need, or add more RAM if this is a daily pattern.
  • The clue: the slowness grows with the number of tabs, which points straight at memory.

📖 Revise: Lesson 3: RAM, the working memory

Why each option is right or wrong

• “Every task, always, by the same amount for each extra core” (Incorrect): A task that must run step by step only uses one core, so extra cores don't speed it up.
• “Storing more files on the computer” (Incorrect): Storage capacity comes from the SSD or hard disk, not the CPU. Cores do work; they don't store files.
• “Keeping data safe after the power goes off” (Incorrect): Nothing in the CPU keeps your data without power. That's the job of storage.
• “Work that can be split into parts that run at once” is correct.

  Each core is an independent worker inside the CPU. More cores let the computer do several things at the same moment, as long as the work can be divided.

  • Good fits: video exports, compiling code, running many apps at once. These can be spread across cores.
  • Poor fits: a step-by-step task where each step needs the last one's result. It uses one core however many you have.
  • So: more cores isn't the same as faster at everything. Speed per core still matters.

📖 Revise: Lesson 2: The CPU and processing

Why each option is right or wrong

• “It was accidentally installed several times” (Incorrect): One installation is enough to start many processes. Task Manager lists what's running, not how many copies are installed.
• “Task Manager shows every program twice by default” (Incorrect): Task Manager shows the real running processes. Several entries mean several processes.
• “Some of the entries must be viruses copying themselves around” (Incorrect): Multiple processes are normal for modern apps. Look for unknown names or odd locations before suspecting malware.
• “One program can start several processes when it runs” is correct.

  A program is the set of instruction files sitting in storage. A process is a running instance of it, with its own memory. Modern apps often start several processes on purpose, for example one for the window and others for background work.

  • Program vs process: installed WhatsApp is a program; WhatsApp running is one or more processes.
  • Why split into processes: if one part crashes, the others can keep going, and the operating system can share CPU time between them.

📖 Revise: Lesson 5: Programs and processes

Why each option is right or wrong

• “SSDs have more processing cores than HDDs” (Incorrect): Cores are processing units in the CPU and GPU, not in storage drives. An SSD has a small controller chip to manage data, but it doesn't add computing cores to the computer.
• “SSDs come with extra RAM built in, so the system loads into the drive itself” (Incorrect): RAM and SSDs are separate parts. An SSD is permanent storage; RAM is fast temporary memory. Upgrading to an SSD does not increase your system RAM.
• “HDDs are unable to store an operating system” (Incorrect): Hard drives can store and run operating systems. Most computers ran Windows, macOS and Linux entirely from HDDs for decades before SSDs became common.
• “Starting means reading thousands of files, and an SSD reads them many times faster” is correct.

  When you turn on your laptop, the operating system (like Windows or macOS) has to load a large amount of data, configuration files and drivers from your storage drive into the system memory (RAM).

  Here is why an SSD handles this task far faster than an HDD:

  • No moving parts: an HDD relies on a spinning platter and a read/write head that must physically move to find data. An SSD uses flash memory (like a giant USB drive) with no moving parts, so it reaches data almost instantly.
  • Small, scattered reads: start-up needs thousands of small files spread across the drive. An HDD has to move its head and wait for the platter to spin round for each one, which takes milliseconds every time. An SSD has no such wait, so these reads finish in a small fraction of the time.
  • Not the whole story: the CPU, RAM and the start-up steps themselves also take time, so the whole start-up speeds up less than the drive's reading does, though still dramatically.

📖 Revise: Lesson 4: Storage, where things are kept

Why each option is right or wrong

• “Restart the whole computer straight away” (Incorrect): This works, but it closes every app and loses all unsaved work. It's a bigger fix than the problem needs.
• “Reinstall the operating system to be safe” (Incorrect): A single frozen app is not a sign the operating system is broken. Reinstalling takes hours and risks your data.
• “Delete the app's files and then download a fresh copy of it” (Incorrect): Deleting files while the app is running can fail or corrupt settings, and it's usually unnecessary.
• “End that app's process in Task Manager or Force Quit” is correct.

  When only one app is stuck, the problem is inside that app's process. Ending just that process frees it without disturbing anything else on the computer.

  • Smallest fix first: you lose only that app's unsaved work, not everything you have open.
  • Where: Task Manager on Windows (Ctrl+Shift+Esc), Force Quit on a Mac (Option+Command+Esc).
  • If it keeps happening: update the app, then look for a pattern, such as one particular file that makes it freeze.

📖 Revise: Lesson 5: Programs and processes

Why each option is right or wrong

• “Yes, the whole database must always fit inside the RAM” (Incorrect): Databases are designed to work with data much larger than memory. Only the actively used parts need to be in RAM.
• “Yes, databases can't be stored on ordinary disks” (Incorrect): Disks (SSDs or HDDs) are exactly where databases are stored permanently.
• “No, because RAM keeps the data when power goes” (Incorrect): RAM loses everything without power. The database is safe because it's stored on disk, not because of RAM.
• “No, only the parts in use right now need to be in RAM” is correct.

  The database lives on storage. The database software keeps the parts it uses most (popular tables, indexes) in RAM and reads the rest from disk when needed.

  • More RAM helps speed: with more RAM, more of the busy data stays in fast memory, so fewer slow disk reads are needed.
  • But it isn't required: databases far larger than RAM are normal. Size the RAM to the data that's actively used, not to the total.

📖 Revise: Lesson 3: RAM, the working memory

Why each option is right or wrong

• “They move to the graphics card automatically” (Incorrect): Apps don't switch to the GPU just because the CPU is busy. Only work written for the GPU runs there.
• “They run on storage instead of the CPU” (Incorrect): Storage holds files; it can't run programs. All programs need the CPU to run.
• “They run normally, because each app gets its own core” (Incorrect): Apps don't own cores. With all four cores busy, every app has to share them, so everything slows down.
• “They slow down, because the CPU has no spare capacity” is correct.

  With every core fully busy, any new work has to wait for a turn. The operating system shares CPU time between all processes, so the export and your other apps each get a slice and everything feels slower.

  • Why exports do this: video encoding splits neatly across cores, so it uses all of them.
  • What you can do: let the export finish, lower its priority, or schedule heavy jobs when you're not using the computer.

📖 Revise: Lesson 2: The CPU and processing

Why each option is right or wrong

• “So the browser uses less RAM overall” (Incorrect): It's the opposite: separate processes use more memory. Chrome accepts that cost for stability and safety.
• “So the tabs load in the order you opened them” (Incorrect): Process separation has nothing to do with loading order. Tabs load as their pages arrive.
• “So all the tabs can share one block of memory efficiently” (Incorrect): Separate processes keep memory apart on purpose, so tabs can't interfere with each other.
• “So one crashing tab doesn't take down the others” is correct.

  Chrome splits its work into separate processes, usually keeping different websites apart, each with its own memory. If a page crashes or misbehaves, usually only the process showing it fails, and the rest of the browser keeps working. It isn't strictly one tab, one process: related tabs can share a process, and parts of a single page from different sites can be split into separate ones.

  • Isolation for safety: a malicious page in one process has a much harder time reading data from another tab.
  • The cost: each process needs its own memory, so Chrome uses more RAM. It's a deliberate trade of memory for stability and security.

📖 Revise: Lesson 5: Programs and processes