Bits, bytes and speed
A computer keeps everything as tiny switches that are off or on: 0 or 1. One 0 or 1 is a bit, the smallest piece of data. Eight bits together make a byte, and a byte is enough for one letter, like the letter S. So the name Salma needs five bytes. Bigger amounts have bigger names. A kilobyte is about a thousand bytes, a megabyte is about a thousand kilobytes, a gigabyte is about a thousand megabytes and a terabyte is about a thousand gigabytes. Each step is about a thousand times bigger, like a staircase where every stair is a thousand times higher. Two more words tell us about speed. Mbps says how fast data travels in a connection, like how wide a pipe is. GHz tells how many steps the processor, the computer’s brain, does in one second. A higher GHz means a faster brain.
| Unit | Size | Good for… |
|---|---|---|
| bit | a single 0 or 1 | one switch |
| byte | 8 bits | one letter |
| kilobyte | about 1000 bytes | a short paragraph |
| megabyte | about 1000 kilobytes | a small photo |
| gigabyte | about 1000 megabytes | many photos or a film |
| terabyte | about 1000 gigabytes | a library of films |
Count the letters. On paper, write your first name. Count the letters, then find the bytes (1 for each letter) and the bits (8 for each byte). Do the same for a friend’s first name and say whose name needs more bits. Then draw a staircase with four stairs and write the four units on it from the smallest to the biggest.