What is a Computer?
P3.computing-fundamentals.01 · Audience: guest, it-ml, language-pro
Every AI model runs on ordinary hardware — a processor, some working memory, and a disk. Before we can explain why large language models need special machines, we need a plain-language picture of the three parts of a computer and what each one does. No electronics required: a professional kitchen is all the intuition you need.
A computer is like a professional kitchen. The CPU is the chef — the one who actually does the work, one task at a time, very fast. RAM is the chef's countertop — where the active ingredients sit, close to hand, but with limited space. Storage (an SSD or hard drive) is the pantry — enormous capacity, but you must walk there to fetch things. Everything a computer does is moving information between these three places.
| Component | What it does | Kitchen analogy |
|---|---|---|
| CPU (processor) | Executes instructions — adds numbers, compares values, decides what to do next (3–5 billion operations per second) | The chef: skilled and fast, but only two hands |
| RAM (working memory) | Holds the data and programs in use right now; the CPU reads and writes it constantly (fast, but limited) | The countertop: instantly reachable, only a few square metres |
| Storage (SSD / hard drive) | Keeps files permanently — programs, documents, model weights — even when the power is off (huge, but slower) | The pantry: enormous capacity, a few steps away |
🗣️ From a linguist's perspective: CPU, RAM, and storage as three time-scales of memory
Quick recap — the three parts
- A computer has three tiers: the CPU (executes instructions), RAM (working memory — fast but limited), and storage (permanent — large but slower).
- The CPU handles one or a few operations at a time; it excels at complex logic but is not built for the massive parallelism AI requires.
- RAM must hold the entire model while it runs — large models (GPT-3 ≈ 700 GB) exceed the RAM of any consumer machine.
- Storage is permanent but slow; loading a model means copying it from storage into RAM every time the program starts.
📚 Go Further
Plain-language reads on how computers work.
| Type | Resource |
|---|---|
| Video | Crash Course Computer Science — how CPU, RAM, and storage work, from first principles (YouTube, free) |
| Video | Computerphile — How Computer Memory Works (YouTube) |
| Reference | Julia Evans — How does a computer know what 2 + 2 is? (jvns.ca) |
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Where next?
Later in Computing Fundamentals