Representation of Basic Information | Computer Architecture & Organisation (CAO) - Computer Science Engineering (CSE) PDF Download

Representation of Basic Information
The basic functional units of computer are made of electronics circuit and it works with electrical signal. We provide input to the computer in form of electrical signal and get the output in form of electrical signal.

There are two basic types of electrical signals, namely, analog and digital. The analog signals are continuous in nature and digital signals are discrete in nature.

The electronic device that works with continuous signals is known as analog device and the electronic device that works with discrete signals is known as digital device. In present days most of the computers are digital in nature and we will deal with Digital Computer in this course.

Computer is a digital device, which works on two levels of signal. We say these two levels of signal as Highand Low. The High-level signal basically corresponds to some high-level signal (say 5 Volt or 12 Volt) and Low-level signal basically corresponds to Low-level signal (say 0 Volt). This is one convention, which is known as positive logic. There are others convention also like negative logic.

Since Computer is a digital electronic device, we have to deal with two kinds of electrical signals. But while designing a new computer system or understanding the working principle of computer, it is always difficult to write or work with 0V or 5V. To make it convenient for understanding, we use some logical value, say, 

LOW (L)   -   will represent     0V and

HIGH (H)   -   will represent    5V 

Computer is used to solve mainly numerical problems. Again it is not convenient to work with symbolic representation. For that purpose we move to numeric representation. In this convention, we use 0 to represent LOW and 1 to represent HIGH. 

0     means    LOW
 1     means    HIGH

To know about the working principle of computer, we use two numeric symbols only namely 0 and 1. All the functionalities of computer can be captured with 0 and 1 and its theoretical background corresponds to two valued boolean algebra. 

 With the symbol 0 and 1, we have a mathematical system, which is knows as binary number system. Basically binary number system is used to represent the information and manipulation of information in computer. This information is basically strings of 0s and 1s.

The smallest unit of information that is represented in computer is known as Bit ( Binary Digit ), which is either 0 or 1. Four bits together is known as Nibble, and Eight bits together is known as Byte.