I'm trying to understand computer storage for a piece of fanfiction, but I know almost nothing about computers, hard drives, or computer science. Could someone explain in very simple terms what bits, bytes, kilobytes, megabytes, gigabytes, terabytes, and the other "-bytes" mean? I'd especially like to know roughly how much information each one can hold and why some explanations use 1,000 while others use 1,024.
3 Answers
A simple scale for your story would be: a bit is one tiny yes/no value; a byte is a small bundle of eight bits; a kilobyte is a short amount of text; a megabyte might hold a book-length amount of plain text or a typical image; a gigabyte can hold hundreds or thousands of images, depending on their size; and a terabyte is roughly a thousand gigabytes. These are only estimates because videos, photos, games, and compressed files can vary wildly in size. Also, a byte does not always equal one written character—modern text can use multiple bytes per character.
The confusing part is that there are two numbering systems. In the decimal system, which storage manufacturers commonly use, 1 kilobyte is 1,000 bytes, 1 megabyte is 1,000 kilobytes, 1 gigabyte is 1,000 megabytes, and 1 terabyte is 1,000 gigabytes. Computers historically worked in powers of two, so operating systems often used 1,024 instead. Technically, the binary versions are called kibibytes (KiB), mebibytes (MiB), gibibytes (GiB), and tebibytes (TiB), although people often use the older names loosely.
Think of bytes as containers for digital information. A bit is the tiniest piece: it can be either 0 or 1. Eight bits make one byte. From there, the prefixes simply describe increasingly large amounts: kilobyte, megabyte, gigabyte, terabyte, petabyte, and so on. As a rough everyday comparison, a photo might be a few megabytes, a game or movie might take several gigabytes, and a 1-terabyte drive can hold an enormous collection of photos, videos, documents, and programs.
That’s why a drive advertised as 1 TB can appear slightly smaller in an operating system: the manufacturer is using decimal terabytes, while the computer may be displaying the capacity using binary units.