Monday, 30 April 2012

System Concept : Data Representation


Computers recognize only two discrete states: on and off. These states can be represented by two digits, 0 and 1. Each 0 or 1 is called a bit in the binary system.

Bit is the  smallest unit of data a computer can process. Bit is a short for binary digit. The binary system has a base of 2 with the two digits (0 and 1). Combinations of 0s and 1s represent larger numbers.

A bit is the smallest unit of data that the computer can process. Bit is a short for binary digit. A bit is represented by the numbers 1 and 0. These numbers represent the binary system. They correspond to the states of on and off, true and false, or yes and no.
All digital data use the binary system to process the information. This information include letters, digits or special character.

Byte is a unit of information built from bits. One byte is equals to 8 bits. Eight bits that are grouped together as a unit. A byte provides enough different combinations of 0s and 1s to represent 256 individual characters.
One byte represents a single character such as the number 3, letter b
or a $ symbol. Bits and bytes are the basis for representing all meaningful information and programs on computers.

8 bits = 1 byte

One byte represents one character such as A, 7, 9 and +.Eight bits that are grouped together as a unit. A byte provides enough different combinations of 0s and 1s to represent 256 individual characters.

For example, the capital letter F is represented by the binary code 01000110 that can be understood by the computer system. Eight bits grouped together as a unit are called a byte. A byte represents a single character in the


There are three character codes to represent characters which are ASCII, EBCDIC and Unicode. Each byte contains eight bits. A byte provides enough different combination of 0s and 1s to represent 256 characters.
The combinations of 0s and 1s are defined by patterns. These patterns are called coding scheme. The 256-character capability of ASCII and EBCDIC is too small to handle the characters that are used by other languages such as
Arabic, Japanese and Chinese.
The Unicode coding scheme is designed to solve this problem. It uses two bytes (16 bits) to represent one character. Unicode will have more than 65,000 different characters. This can
cover all the world’s languages.


ASCII pronounced as "ask-key" stands for the American Standard Code for Information Interchange and was proposed by ASA (American Standard Association) in 963 and was finalised in 1968.ASCII is a standard of 7-bit code used to represent characters, which include letters, numbers and punctuation marks.

7 bits allow the computer to encode a total of 128 characters for the numbers 0-9, uppercase and lowercase letters A-Z and a few punctuation symbols. However this 128 bit  code only suitable for english language speaking users.

IBM and Apple expanded the amount of space reserved for the character codes to 8-bits, equivalent to 1 byte.


ASCII was established to achieve compatibility between various types of data processing equipment making it possible for the components to communicate with each other successfully.

ASCII enables manufacturers to produce components that are assured to operate correctly in a computer.

ASCII makes it possible for humans to interact with a computer. It also enables users to purchase components that are compatible with their computer configurations.


When you press a key, for example the letter D on your keyboard, the electronic signal is sent to the CPU for the computer to process and store in memory. Every character is converted to its corresponding binary form. The computer the processes the letter as a byte., which actually a series of on and off of electrical states. When the computer is finished processing the byte, the software installed in the system convert the byte back which is then displayed in the screen.  In this example, the letter D is converted to 01000100.

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