How is Data Actually Stored in a Computer?
Numbers are made up of digits, so we could say that computers only understand digits. Because of this, we say that computers are digital devices.
The solution is to use numeric codes:
- Different letters in a text document are given different numeric codes
- Different pixels (coloured dots) in an image are given different numeric codes
- Different sounds in a music file are given different numeric codes
If you took a peek inside the memory of a computer you might see the following Binary numbers:
What is a Bit?
Because it is a binary digit, a bit can only have the value 0 or 1. (This is different from our normal decimal digits which can have any value between 0 and 9.)
This binary number is four bits long: 1101
What is a Byte?
Here is are a bunch of bytes (all exactly 8 bits long):
Bytes are the standard unit of storage for all computing devices: Hard drive size is measured in bytes, file size is measured in bytes, RAM size is measured in bytes.
So, next time someone tells you that they have a 500 GB hard drive, you will know that it can store 500 billion bytes of data.
- can store 500GB of data (500 billion bytes)
- has a cache of 16MB (16 million bytes)
- can transfer data at a rate of 3Gb/s (3 billion bits per second)