History and Evolution of Computers

HISTORY & EVOLUTION OF COMPUTERS:

The computer may be classified into a number of generations. The classification may be based on:

Generations of Computers Based on Hardware:

 

First Generation Computers: (1945 -55)

• The computer started with ENIAC.
• 1951: It was then followed by the IBM UNIVACI (Universal Automatic Computer) built by Mauchly & Eckert.
• This machine could perform business data processing.
• Used: Vaccum tubes.
• Because of vacuum tubes, computers were;
• Very large,
• Required lot of energy
• Slow Input/Output
• Suffered from heat & maintenance problems.
• Language: Machine level language or machine language, Binary language.

Second Generation Computers: (1955 -65)

• The Transistors were used in second-gen. computers- to overcome the difficulties faced in the first generations due to the use of vacuum tubes.
• Transistor: It is a small component made of semiconductor devices. 
• Benefits after use of transistors; 
• the problems of heat were minimized.
• The computer size was reduced.
• Storage capacity - improved.
• Machine language is replaced by higher-level languages: ALGOL, FORMAN.
• Example of second-gen. computers: IBM 1620.

Third Generation Computers: (1965 -80)

• The transistor is replaced by Integrated Circuits (IC).
• These circuits are fixed on the silicon chip.
• The silicon chip consumes less than 1/8th of an inch square on which 10 computer studies: 9 many electronic components like diodes, transistors, capacitors, etc. can be fixed.
• The wire interconnections about the components of the circuit are minimized.
• These computers were: smaller, faster & more flexible in terms of Input/Output.
• It also satisfied the need for small business & computers became popular as "Minicomputers".
• Language: C, COBOL, JAVA.
• Example of third-gen. computers: IBM 360, PDP8, PDP11.

Fourth Generation Computers: (1980 -89)

• The computer used large scale IC called VLSI (Very Large Scale Integration)
• Because of VLSI, computers were: faster, smaller, reliable.
• It soon evolved as interactive general-purpose machines that allow rapid application development.
• It became more user-friendly & can be used widely for personal applications. Hence, it is called- "Personal Computers" (PC).
• These computers can process billions of instruction/sec.
• They are used for applications that require intensive numerical computations such as stock analysis, weather forecasting & other similar complex applications.
• Language: SQL (Structured Query Language)
• Example of fourth-gen. computers: IBM PC, Apple II, Supercomputer CRAY.

Fifth Generation Computer: (1989 -till)

• The computers made smarter in terms of processing speed, user-friendliness & connectivity to the network.
• These computers are portable & sophisticated.
• The key features of the computers: Powerful desktops, notebooks, variety of storage mechanisms such as optical disks & advanced software technology such as OS & AI.
• The languages are designed to make the computer solve as a given problem without the programmer. Example; voice recognition & intrusion detection. It uses AI techniques to meet their goal.
• Artificial Intelligence (AI): can handle imprecision & supports human-like self-learning & problem-solving.
• Example of fifth-gen. computers: IBM notebooks, Param 10000, Pentium PC.

Generations of Computer-Based on Software:

• Software plays a vital role in computer systems by creating a bridge between computer hardware & computer user.
• It can be considered as "Soul of Computer", without which the computer can't work.
• Software is an organized collection of data & instructions given to computers in order to perform a given task. These components are data, instructions & documents about the software such as comments.
• Program: The set of instructions.
• Programming: The process of writing or coding.
• Programmers: An individual who performs the programming or coding task.

There are two major types of software:

System Software:

• It manages computer hardware & acts as an interface between computer hardware & software developed for business applications.
• It provides functionalities like;
• Booting computers properly, 
• Managing memory, 
• Channeling data from secondary memory to primary memory,
• Example of system software: Operating system, Translator program.
• Compiler: Some translator programs transform the whole source code written in a programming language (the source language) into another computer language- target language, binary language. Later the translated code is computed to the desired results.
• Interpreters: Some translators program transform the source code into the target code in line by line fashion & produce the result at the same time.
• Since interpreters try to convert the source program line by line, they can concentrate on a single line, hence it is not possible to analyze the source code.
• Compliers are fast in comparison to interpreters.

Application Software:

• It is a set of computer instructions that provide specific functions to users.
• These functionalities may be general-purpose like- word processing or maybe very narrow, such as an organization's payroll program that generates pay-slips in the company's format, on the company's preprinted stationery.
• It also supports business applications like printing reports from data stored, calculating bills, generating pay-slips, marking attendance, printing students' mark-sheets, etc.
• Special software needs to be developed for this type of application support.