RAM (Random Access Memory) is your computer's short-term memory. It temporarily stores data that the CPU is actively using — like an open browser tab, a running program, or a document you're editing.
Unlike your hard drive, RAM is volatile — it loses everything the moment you turn off your computer. But it's also extremely fast, which is why the CPU uses it instead of reading from the hard drive every time.
■ In use ■ Currently active ■ Free
Why more RAM = faster computer
If your RAM fills up, the OS starts using a portion of your hard drive as "virtual memory" — which is 100x slower. More RAM means more programs can run simultaneously without this slowdown.
Real world analogy: RAM is your desk. Your hard drive is the filing cabinet across the room. You work on what's on your desk — fast. When the desk is full, you have to keep walking to the cabinet — slow.
An algorithm is a precise, step-by-step set of instructions for solving a problem. It takes an input, processes it, and produces an output — every time, predictably.
Algorithms are not code. They are the idea behind the code. You can write the same algorithm in Python, Java, or any language — the logic stays the same.
A simple example — making tea
What makes a good algorithm?
Three things: it must be correct (gives the right answer), efficient (doesn't waste time or memory), and clear (someone else can follow it).
Key insight: The entire field of Computer Science is essentially the study of algorithms — how to design them, analyse them, and improve them.
A data type tells the computer what kind of value a variable holds — and therefore how much memory to allocate and what operations are allowed on it.
Every piece of data in a program has a type. Even if you don't declare it explicitly (like in Python), the computer still tracks it internally.
Why it matters: Using the wrong data type wastes memory and causes bugs. Storing a phone number as an int instead of a str would strip leading zeros — a classic beginner mistake.
The Internet is a global network of computers connected to each other, communicating through a shared set of rules called protocols. The most important of these is TCP/IP.
When you open a website, your browser sends a request across this network to a server somewhere in the world, which sends back the page data — all in milliseconds.
What happens when you type a URL
Internet vs World Wide Web
These are not the same thing. The Internet is the physical infrastructure — cables, routers, servers. The Web is just one service that runs on top of it, using HTTP. Email, FTP, and SSH are other services that also run on the Internet but are not the Web.
Key fact: Every device on the Internet has an IP address — a unique numerical label like 192.168.1.1 — that identifies it on the network, just like a postal address identifies a house.
A compiler translates human-readable source code (like C or Java) into machine code — the binary instructions a CPU can directly execute. Without a compiler, your code is just text.
Python uses an interpreter instead — which translates and runs code line by line rather than all at once. This is why Python is slower than compiled languages but easier to work with.
The compilation process
Compiler vs Interpreter: A compiler translates the whole program at once before running it. An interpreter translates and runs it one line at a time. Compiled = faster at runtime. Interpreted = easier to debug and test.
Boolean logic is the foundation of all computing. Every decision a computer makes — every if/else, every condition — ultimately reduces to boolean values: True (1) or False (0).
Named after mathematician George Boole, it uses three fundamental operations: AND, OR, and NOT. All other logic can be built from these three.
Truth tables
| A | B | A AND B | A OR B | NOT A |
|---|---|---|---|---|
| False | False | False | False | True |
| False | True | False | True | True |
| True | False | False | True | False |
| True | True | True | True | False |
In Python
Why it matters: Every logic gate in a CPU is built from boolean operations. Billions of AND, OR, NOT operations happen every second inside your computer — all reducible to 1s and 0s.