Data definition (informatics)

A datum is a symbolic representation (numerical, alphabetic, etc.) of an attribute of an entity. A datum has no semantic value (meaning) in itself, but when processed it can be used to perform calculations or make decisions.

The data is likely to be compressed, encrypted, transmitted and stored.

At its most rudimentary level, the data in a computer is a lot of ones and zeros, known as binary data. Because all computer data is in binary format, it can be created, processed, saved, and stored digitally.

Data and information: difference

«Data» and «information» are often used interchangeably; however, a data set is informative to someone if they know what to expect or the meaning of the data.

For example: 14, 15, 15, 15, 15, 14, 14, 13 are numeric data. They become information when we know what the ages of a group of children in a class are.

The amount of information content in a data stream can be characterized by its Shannon entropy.

For more information read: Difference between information and data.

How data is stored on a computer

Data in a computer is converted into binary digital form, and is represented in a series of bits. Bits are the basic unit of measurement for data, and are binary digits that can only store two values: 0 and 1. These two values ​​correspond to the electrical values ​​of power off (zero, false, no value) and power on (one, false). true, with value)

Bits are the smallest value of data in a computer, but the smallest amount of data that can be accessed by a system (or «address») is a byte, which consists of 8 bits put together. A byte is so small that it contains 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 equal powers of two instead of powers of ten.

Therefore, a kilobyte (kB) is 1,024 bytes, or 2 to the 10, not 1,000 or 10 to the 3 as goat would expect. The next commonly used increments today are the megabyte (1 MB = 1,024 kB), the gigabyte (1 GB = 1,024 MB), and the terabyte (1 TB = 1,024 GB).

Larger units are used to describe large amounts of 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)

For more information on this read: Storage Units of Measurement.

Computer systems operate on «words» consisting of four bytes. The central processing unit (CPU) of a computer can handle only a given number of words at a time. Most computer systems operate at 32, 64, or 128 bits, corresponding to one, two, or four words, respectively.

Data consists of all information stored on a computer or shared over the Internet (such as videos, sounds, images, and text).

To get a better understanding of what corresponds to a given data unit in the real world, here are some practical examples:

A medium-sized novel: 1 MB
Listen to high-quality music: 115.2 MB per hour
Sending 1,500,000 WhatsApp messages: 1 GB
More than five hours of watching YouTube videos: 1 GB
One hour of watching 4K videos: 7.2 GB
All books in a large library or 1,600 data CDs: 1 TB
The file size of the original Super Mario Bros NES cartridge: 32 kB

related terminology

information

digital information

Database

data validation

data integrity

data redundancy

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