Learn · Computer Science · Class 6

Computer Hardware & Software

The physical machine, the instructions that run on it, and how they meet.

10 parts
Scroll to begin ↓
📘 DefinitionTwo halves of one systemPart 1 of 10
🧩 The partsThe main hardware componentsPart 2 of 10
🔍 In detailTypes of softwarePart 3 of 10
✏️ Worked exampleWhy more RAM speeds things upPart 4 of 10
🔍 In detailHow a computer stores everything as numbersPart 5 of 10
✏️ Worked exampleDiagnosing a slow computerPart 6 of 10
🌍 In the real worldChoosing a computerPart 7 of 10
⚠️ Common mistakesWhere it usually goes wrongPart 8 of 10
✅ SummaryWhat to rememberPart 9 of 10
✏️ Worked exampleWatch one worked throughPart 10 of 10
1📘 DefinitionPart 1 / 10

Two halves of one system

Hardware is everything physical, the parts you could drop.

Software is the instructions, programs and data, which have no physical form.

A USB stick is hardware; the files on it are software. Buying a more expensive computer does not make your software better, and installing a program does not add hardware. Keeping the two clear explains most computer problems.

2🧩 The partsPart 2 / 10

The main hardware components

  • CPU: the processor. Executes instructions; measured in GHz.
  • RAM: working memory. Fast, volatile. It empties when power is lost.
  • Storage: hard disk or SSD. Slower, but keeps data permanently.
  • Motherboard: the board everything plugs into and communicates through.
  • Power supply, graphics card, and the input/output devices.

An SSD has no moving parts, which is why it is faster and more robust than a spinning hard disk.

3🔍 In detailPart 3 / 10

Types of software

System software runs the machine itself.

  • Operating system: Windows, macOS, Linux, Android. Manages memory, files, and every program.
  • Utilities: antivirus, backup, disk tools.
  • Drivers: let the OS talk to a specific printer or graphics card.

Application software does a job for you: word processors, browsers, games, editors.

The relationship: applications do not talk to hardware directly. They ask the operating system, which handles the hardware, which is why the same app can run on many different machines.

4✏️ Worked examplePart 4 / 10

Why more RAM speeds things up

The situation. Your computer becomes slow when many programs are open.

What is happening: the CPU can only work with data in RAM. When RAM fills up, the operating system moves some of it onto the much slower storage disk to make room.

Then, when that data is needed again, it must be copied back, and the disk is many times slower than RAM. The computer spends its time shuffling data instead of working.

Which is why: adding RAM often makes an old computer feel dramatically faster, while adding storage does nothing for speed at all.

And why closing unused browser tabs helps, each one is holding RAM.

5🔍 In detailPart 5 / 10

How a computer stores everything as numbers

Computers use binary, only 0 and 1. Everything is built from that.

Why only two digits? Because a circuit is easy to build with two reliable states: current flowing or not, high voltage or low. Ten distinguishable states would be far harder to build accurately.

1 bit = one 0 or 1
8 bits = 1 byte
1024 bytes = 1 kilobyte (KB)
1024 KB = 1 megabyte (MB)
1024 MB = 1 gigabyte (GB)

How other things become numbers: each letter has a number code; a colour is three numbers for red, green and blue; a sound is thousands of measurements per second.

Everything on a computer is numbers. Text, music, photographs and video are all the same thing underneath, interpreted differently.

6✏️ Worked examplePart 6 / 10

Diagnosing a slow computer

Understanding hardware lets you reason about problems instead of guessing.

Slow when many programs are open → not enough RAM.

Slow to start up and open files, fine afterwards → slow storage; an SSD would help.

Slow at everything, even one program → the CPU is the limit.

Slow only online → not the computer at all. That is the network.

Fine when cold, slow after an hour → overheating; the CPU deliberately slows itself to avoid damage. Often just dust blocking a fan.

The method: notice when it is slow, and that narrows down what is limiting it. This is how technicians actually work.

7🌍 In the real worldPart 7 / 10

Choosing a computer

For schoolwork and browsing: modest CPU, 8 GB RAM, an SSD. The SSD matters more than the processor for how fast it feels.

For photo or video editing: more RAM and a better processor.

For gaming: a graphics card becomes the main thing.

The common mistake: buying based on storage size. 1 TB of slow disk is worse for daily use than 256 GB of SSD.

And software costs. Free alternatives (LibreOffice, GIMP, Linux) do most of what paid software does. Pirated software is both illegal and a common source of malware, which makes it a poor bargain twice over.

8⚠️ Common mistakesPart 8 / 10

Where it usually goes wrong

  • "More storage means faster." RAM and CPU affect speed.
  • Confusing RAM and storage. RAM empties.
  • "The CPU is the whole computer."
  • "Apps talk to hardware directly." The OS is in between.
  • "1 GB is 1000 MB." It is 1024.
9✅ SummaryPart 9 / 10

What to remember

  • Hardware physical · software instructions.
  • CPU processes · RAM is fast and empties · storage keeps.
  • Applications reach hardware through the operating system.
  • Everything is stored in binary.
10✏️ Worked examplePart 10 / 10

Watch one worked through

Here is one done slowly, with the reason for every move. Then one for you.

Watch one first

A computer takes two minutes to start up and files open slowly, but once a program is running it is fine. Which component is to blame?

  1. Match the symptom to a stage. Starting up and opening both mean reading stored data.
    slow to START + slow to OPEN → reading from storage
    Diagnose from what the machine is doing when it is slow. Each component fails with its own symptom.
  2. Rule out RAM: a RAM shortage shows when many programs are open at once.
    RAM ✗ (that symptom is absent)
    Saying why you ruled something out is worth as much as naming the answer. It shows reasoning, not guessing.
  3. Rule out the CPU: a slow processor would also slow a program once open.
    CPU ✗ (programs run fine)
    The CPU affects work happening now, so its symptom is constant rather than only at the start.
  4. Storage is what is left.
    STORAGE ✓ hard disk → SSD
    Storage is the slowest part to read from, which is why an SSD changes how fast a machine feels more than a faster CPU does.

Answer: Storage. A hard disk is slow to read, so fitting an SSD would fix it.

Now you try

Which component empties when the power is lost? One word.

Show the answer

RAM

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