Bits and bytes
A bit is a single binary value, often explained as 0 or 1. A byte is commonly eight bits. Many file sizes, memory amounts, and storage capacities are measured using bytes and larger units.
| Unit | Simple meaning | Common use |
|---|---|---|
| Bit | One binary value | Smallest basic data unit |
| Byte | Eight bits | Text characters and file sizes |
| Kilobyte | Thousands of bytes approximately | Small files |
| Megabyte | Millions of bytes approximately | Photos, documents, apps |
| Gigabyte | Billions of bytes approximately | Storage and memory |
| Terabyte | Trillions of bytes approximately | Large drives and backups |
Text as numbers
Computers store text by mapping characters to numbers using encoding systems. The visible letter is human friendly, but the computer stores a code.
Images and sound as samples
Digital images store color values for pixels. Digital audio stores samples of sound waves. Video stores sequences of images plus audio and timing information.
Compression
Compression reduces file size by representing information more efficiently. Some compression keeps exact data, while other compression sacrifices detail to save space.
human idea -> encoding -> bits and bytes -> storage or processing -> decoded output
Binary questions
Electronic systems can represent two stable states very reliably. Binary is simple for circuits, even when higher level software hides it from users.