UNIT 1

Programming language Introduction to Computers, Characteristics of a Computer , Definition of Computer, Limitations of Computer , Generation Of Computer Classification of Computers, According to size, Super Computers , ROM (Read Only Memory),EEPROM (electrically erasable programmable read-only memory),Secondary Storage Device,NUMBER SYSTEMS .


Introduction to Computers

A Computer is an electronic device, which takes input from the user in the form of data and instructions, it processes the data and generates output and displays it to the user.It is an electronic device which processes given data to derive the required and useful information. During the processing the computer has to perform various functions like
(i) Accepting Instructions & data from the user.
(ii)Performing various arithmetic and Logical operations as per Instructions given.
(iii)Presenting the Information or Output to the user.

Characteristics of a Computer


Definition of Computer

A Computer is an electronic device, which takes input from the user in the form of data and instructions, it processes the data and generates output and displays it to the user. A computer performs the following tasks:

Limitations of Computer

Computer does not work on itself:-it requires set of instructions to be provided, else computer (Hardware) is waste.
Computers are not intelligent:-they have to be instructed about each and every step which they have to perform
Computers cannot take decisions on its own:- one has to program the computer to take an action if some condition prevails.
Computers, unlike humans cannot learn by experience.

Generation Of Computer


Generation in computer terminology is a change in technology a computer is/was being used. Initially, the generation term was used to distinguish between varying hardware technologies. But nowadays, generation includes both hardware and software, which together make up an entire computer system. There are totally five computer generations known till date such as


Classification of Computers

Analog Computers
An analog computer is a form of computer that uses continuous physical phenomena such as electrical, mechanical, or hydraulic quantities to model the problem being solved.
It operates by measuring rather than counting. It uses continuous signals as input.
Examples: Thermometer, Speedometer etc.
Digital Computers
Operate essentially by counting
All quantities are expressed as discrete or numbers.
A computer that performs calculations and logical operations with quantities represented as digits, usually in the binary number system
These are the systems that are computationally complete and capable of solving all of the problems that can be solved algorithmically.
Examples: Desktop, laptop etc
Hybrid Computers (Analog + Digital)
A combination of computers those are capable of inputting and outputting in both digital and analog signals. A hybrid computer system setup offers a cost effective method of performing complex simulations.
It use both types of signals analog as well as digital as input.
Mostly used with process control equipments in continuous production plants e.g., oil refineries, Areas of application are nuclear power plants, mines, intensive care units of hospitals (ICUs), chemical process plants etc.

According to size

According to size, the computers can be categorized as