Data representation is defined as the methods used to represent information in computers. Different types of data can be stored in the computer system.
This includes numeric data, text, executable files, images, audio, video, etc. all these will look different to us as human.
Methods of Data Representation in Data Communication
- Decimal Numbers
- Binary Numbers
- Hexadecimal Numbers
However, all types of information or data stored in the computer are represented as a sequence of 0s and 1s.
As human we are used to writing numbers using digits 0 to 9. This is called base 10.
This number system has been widely adopted, in large part because we have 10 fingers.
However, other number systems still persist in modern society.
Any positive integer (whole number) can be represented by a sequence of 0s and 1s.
Numbers in this form are said to be in base two, and are called binary numbers.
Computers are based on the binary (base 2) number system because electrical wire can only be of two states (on or off).
Writing numbers in binary is tedious since this representation uses between 3 to 4 times as many digits as the decimal representation.
The hexadecimal (base 16) number system is often used as shorthand for binary. Base 16 is useful because 16 is a power of 2, and numbers have roughly as many digits as in the corresponding decimal representation.
Another name for hexadecimal numbers is alpha decimal because the numbers are written from 0 to 9 and A to F. where A is 10, B is 11 up to F that is 15.
American Standard Code for Information Interchange (ASCII code) defines 128 different symbols. The symbols are all the characters found on a standard keyboard, plus a few extra.
Unique numeric code (0 to 127) is assigned to each character.
In ASCII, “A” is 65, “B” is 66, “a” is 97, “b” is 98, and so forth. When a file is save as “plain text”, it is stored using ASCII.
ASCII format uses 1 byte per character 1 byte gives only 256 (128 standard and 128 non-standard) possible characters.
The code value for any character can be converter to base 2, so any written message made up of ASCII characters can be converted to a string of 0s and 1s.
Graphics on computer screen are consists of pixels. The pixels are tiny dots of color that collectively paint a graphic image on a computer screen.
It is physical point in a raster image, or the smallest addressable element in an all points addressable display device. Hence it is the smallest controllable element of a picture represented on the screen.
The address of a pixel corresponds to its physical coordinates. LCD pixels are manufactured in two-dimensional grid, and are often represented using dots or squares, but CRT pixels correspond to their timing mechanism and sweep rates.
The pixels are organized into many rows and columns on the screen.