Jump to content

1.5 How a Computer Works

From Computer Science Knowledge Base
Revision as of 21:13, 11 July 2025 by Mr. Goldstein (talk | contribs)

How a Computer Works: The Grand Tour!

Imagine a computer isn't just a mysterious box, but a super-smart factory or a busy team of specialized workers. To understand how it works, we're going to take a tour of its most important parts and see how they all work together to make magic happen!

At its heart, a computer is a machine that takes in information (input), processes it, stores it, and then gives you back results (output). It's all about following instructions, super-fast!

1. Input: Getting Information In

Before a computer can do anything, it needs to receive instructions or data from you or the world around it. This is called input.

  • Keyboard: When you type a letter, you're sending a tiny electrical signal to the computer that represents that letter.
  • Mouse/Trackpad: Moving the mouse or clicking sends signals about position and clicks.
  • Microphone: Your voice is turned into digital information (numbers) that the computer can understand.
  • Camera: A camera captures light and turns it into a grid of numbers (pixels) that represent an image or video.
  • Touchscreen: When you tap or swipe, sensors detect the pressure and location, sending that as input.
  • Sensors: In things like smartphones or smartwatches, tiny sensors can detect motion (accelerometer), direction (compass), light levels, or even your heartbeat.

Think of it like this: Input devices are the computer's senses – its eyes, ears, and touch. They allow it to perceive and receive information from the outside world.

Bibliography:

Further Reading:

2. Processing: The Brains of the Operation

Once the information is in the computer, the real work begins. This is where the computer crunches numbers, makes decisions, and follows instructions.

2.1 The CPU (Central Processing Unit)

The CPU is the "brain" of the computer. It's a tiny chip, but it's incredibly powerful. Its main job is to carry out instructions from computer programs.

  • Executing Instructions: Every time you open an app, click a button, or play a game, the CPU is rapidly performing billions of calculations and following precise steps.
  • Cores: Modern CPUs often have multiple "cores." Think of each core as a mini-brain. A dual-core CPU has two brains working together, allowing the computer to do more things at the same time (multitasking) more efficiently.
  • Clock Speed: CPUs are measured in "gigahertz" (GHz). This is like how many cycles per second the CPU can perform. A higher GHz generally means a faster CPU.

Think of it like this: The CPU is the main chef in the kitchen. It reads the recipe (instructions from a program) and does all the chopping, mixing, and cooking (calculations and operations). If it has multiple cores, it has several chefs working together.

Bibliography:

Further Reading:

2.2 The GPU (Graphics Processing Unit)

While the CPU is good at general tasks, the GPU is a specialized brain for handling graphics and images.

  • Visuals: The GPU is super-efficient at drawing shapes, colors, and textures on your screen. This is crucial for smooth video playback, realistic 3D games, and complex animations.
  • Parallel Processing: GPUs have thousands of small "cores" that can work on many simple tasks at the exact same time. This is perfect for graphics, where you need to calculate the color for millions of pixels all at once.

Think of it like this: If the CPU is the main chef, the GPU is the specialized artist in the kitchen. It quickly colors all the plates and makes sure the food presentation is perfect and visually appealing.

Bibliography:

Further Reading:

3. Memory: The Computer's Workspace and Storage

Computers need places to store information, both temporarily while they're working and permanently for later use.

3.1 RAM (Random Access Memory) - Short-Term Memory

RAM is like the computer's short-term memory or its desk space.

  • Fast and Temporary: It's super fast, allowing the CPU to quickly read and write data. However, it's "volatile," meaning all the information in RAM is erased when you turn off the computer or restart it.
  • Active Programs: When you open a program or a file, the computer loads it from long-term storage into RAM. This is why programs open faster the second time you use them (they might still be in RAM). The more RAM you have, the more programs and tabs you can have open smoothly at once.

Think of it like this: RAM is the kitchen counter. The chef (CPU) needs ingredients (data) right where they can grab them quickly to work on a dish (program). There's only so much counter space, and everything gets cleared off when the kitchen closes (computer turns off).

Bibliography:

Further Reading:

3.2 Storage (Hard Drive/SSD) - Long-Term Memory

This is where the computer keeps your files, programs, and the operating system permanently.

  • Hard Disk Drive (HDD): Older computers often used HDDs. These store data on spinning magnetic platters, like tiny record players. They are cheaper for large amounts of storage but are slower and have moving parts.
  • Solid State Drive (SSD): Newer computers use SSDs. These store data on flash memory chips, similar to a giant USB stick. They are much faster, more durable (no moving parts), and use less power, but are generally more expensive for the same amount of storage.
  • Non-Volatile: Unlike RAM, data on a hard drive or SSD stays there even when the computer is turned off.

Think of it like this: Long-term storage is the pantry or refrigerator in the kitchen. It's where you keep all your ingredients (files and programs) safely stored for a long time, even when the kitchen is closed. It takes a little longer to get something from the pantry than from the counter.

Bibliography:

Further Reading:

4. Output: Showing You the Results

After the computer has processed information, it needs a way to show you what it has done. This is called output.

  • Monitor/Screen: This is the most common output device, displaying text, images, and videos.
  • Speakers/Headphones: These convert digital audio signals back into sound waves you can hear.
  • Printer: Takes digital documents and creates physical copies on paper.
  • Projector: Displays the computer's output onto a large screen or wall.
  • Haptic Feedback: In phones or game controllers, this refers to vibrations that give you a physical sensation as output (e.g., feeling a buzz when you type).

Think of it like this: Output devices are the computer's ways of communicating back to you – its voice, its drawing board, or its printer.

Bibliography:

Further Reading:

Putting It All Together: The Information Flow

So, how does it all work in action? Let's trace a simple example: You open a game.

  1. Input: You click the game icon with your mouse (input).
  2. Storage: The OS (Operating System) tells the CPU to find the game program on your hard drive/SSD (long-term storage).
  3. Memory: The game program is loaded from the hard drive/SSD into RAM (short-term memory) so the CPU can access it quickly.
  4. Processing (CPU): The CPU starts executing the game's instructions. It tells the GPU to start drawing the game's graphics.
  5. Processing (GPU): The GPU quickly calculates all the colors and shapes for each frame of the game.
  6. Output: The images generated by the GPU are sent to your monitor (output), and the game's sounds are sent to your speakers (output).
  7. Loop: As you play, your keyboard and mouse send constant input signals. The CPU and GPU process these signals, update the game world in RAM, and send new images and sounds to your output devices, all happening many times per second!

This constant cycle of input, processing, memory access, and output is the fundamental way almost all computers operate, from tiny smartwatches to giant supercomputers. It's a symphony of parts working together at incredible speeds!

Further Resources

How a Computer Works - from silicon to apps. (2021, January 17). Improbable Matter, retrieved from https://youtu.be/5f3NJnvnk7k?si=QK4deYyeVDwUfAW4

How does Computer Hardware Work? [3D Animated Teardown] (2023, March 22). Branch Education, retrieved from https://youtu.be/d86ws7mQYIg?si=9LUDBcVQ_Q_xbMA5

How do computers actually work? From electrons to hardware to the web. (2024, March 11). Tejas Kumar, retrieved from https://www.youtube.com/embed/G-Js3CcD000?si=5YJ08Dae1nGe6xib

Chapters

00:00 -Intro

01:17 - Sponsor

02:47 - Everything is a Stack, with Layers on Layers

04:55 - The Lowest Layer: Subatomic Particles

09:21 - Types of Current: AC and DC (Alternating and Direct Current)

12:36 - How Datacenters use Electricity

15:45 - The Next Layer: Hardware

19:07 - The Next Layer: Firmware

21:46 - The Next Layer: The OS Kernel

24:21 - Diving Deeper: Motherboard

27:59 - The OS Kernel

29:43 - CPU, Threading, Multithreading, Hyperthreading, Clock Speed

36:53 - Memory/RAM, Volatile Memory, Virtual Memory

39:43 - Storage, Hard Drives, Solid State Drives

41:33 - TPM (Trusted Platform Module)

42:59 - The Next Layer: Software

43:46 - Software Architecture

47:08 - Frontend Deep Dive: HTML, HTMX, CSS, TailwindCSS, JavaScript, Accessibility, and Network

59:53 - What happens when data fetching: TCP/IP stack, HTTP and SSL encryption, how data flows over the network and internet

01:12:05 - Receiving a Network Request on the Backend, DNS, Firewalls, Load Balancing, SSL Termination, Reverse Proxies

01:20:38 - Backend Architecture: Caches, Queues, Distributed Systems, Control Plane vs. Data Plane

01:25:44 - Cloud Computing: Virtual Private Clouds (VPCs), Subnets, NATs

01:28:30 - Adjusting Expectations for Frontend and Backend

01:29:34 - CI/CD Pipelines, Webhooks, git-based deploys

01:30:21 - Build it or buy it?

01:31:18 - Conclusion

Retrieved from "https://wiki.omnivision.website/index.php?title=1.5_How_a_Computer_Works&oldid=426"