Data in a computer is information converted into a binary digital form, and it is represented in a series of bits. Bits are the basic measurement unit of data, and are binary digits that can only store two values: 0 and 1. These two values correspond to the electrical values of off (zero, false, no value) and on (one, true, value). Bits are the smallest increment of data on a computer, but the smallest amount of data that a system can access (or "address") is a byte, which consists of 8 bits assembled together. A byte is so small that it contains just enough information to store a single ASCII character.
Since computers use binary (base two) math instead of a decimal (base ten) system, all subsequent increments in data storage units equate to powers of two rather than powers of ten. Therefore, a kilobyte (kB) is 1,024 bytes, or 210, not 1,000 or 103 as might be expected. The next increments commonly used today are the megabyte (1 MB = 1,024 kB), the gigabyte (1 GB = 1,024 MB) and the terabyte (1 TB = 1,024 GB). Higher increments are used to describe big data, and include the petabyte (1 PB = 1,024 TB), the exabyte (1 EB = 1,024 PB), the zettabyte (1 ZB = 1,024 EB) and finally the yottabyte (1 YB = 1,024 ZB).
Computer systems operate in "words" consisting of four bytes. The central processing unit (CPU) of a computer can handle only a given number of words at one time. Most computer systems operate at 32, 64 or 128 bits, which correspond, respectively, to one, two or four words.
Data consists of all the information stored on a computer or shared across the internet (such as videos, sounds, images, and text). Today, the data transferred between a network and the internet or a smartphone depends on the plan subscribed to by a given user, and is generally measured in gigabytes ("gigs"), represented by the symbol GB. Different plans provide the user with different numbers of gigs provided recurrently (usually every month) by the provider. These GBs are eventually "consumed" as data is downloaded and uploaded by browsing the web, reading and sending emails, watching videos and so forth.
To have a better understanding of what a given unit of data corresponds to in the real world, here are a few practical examples:
- A medium-sized novel: 1MB
- Listening to high-quality streaming music: 115.2 MB per hour
- Sending 1,500,000 WhatsApp messages: 1 GB
- Over five hours of watching YouTube videos: 1 GB
- One hour of watching 4K videos: 7.2 GB
- All of the books in a large library or 1,600 CDs' worth of data: 1 TB
- The file size of the original Super Mario Bros NES cartridge: 32 kB
It is funny to think how just 32 kB of data have been able to change the lives of so many people across the world, isn't it?