History of Computers

History of Computers

Computers are not a work of a day. The concept of computer has developed from the time immemorial. From the first counting tool to the modern day computer, it has taken more than 5000 years. And the story of computers has not stopped yet. Computers are still developing. In terms of modern age computer, we are currently living in the age of fifth generation computers which can perform millions of task (or calculations) in one second alone.

Abacus
Abacus is thought to be the first mechanical computing device. The first iteration of abacus was developed by the Sumerians (Mesopotamians) around 2500 B.C, but it was truly developed and perfected by the Chinese educationists around 2nd century AD. It is made up of a frame in which rods are fitted across with rounds beads sliding on the rod. It is still used in China, Russia and Japan.

Napier's Bones
Napier's bones were developed by the John Napier (1550-1617). It can perform multiplication and divisions on numbers using a method called lattice multiplication, also known as rabdology. Napier's bones were set of 9 numbered rods made up of ivory or bones. The device popularized the use of decimal notations in European world. Furthermore, it can be used to perform addition and subtraction.

Pascaline
Pascal's calculator (Pascaline) is a mechanical calculator invented by Blaise Pascal around 1642. It was first pure mechanical adding machine. It was structured like a rectangular box with eight disc that represents number of units. It can perform the addition and subtraction. Thus, also known as adding machine. The term carry was introduced with introduction of Pascaline.

Jacquard Machine (Card of Holes for Weaving Patten)
The Jacquard Machine was invented by the Joseph Jacquard in 1804. It was based on earlier inventions by Basile Bouchon (1725), Jean Baptiste Falcon (1728), and Jacques Vaucanson (1740). It was controlled by a "chain of cards"; a number of punched cards laced together into a continuous sequence. It simplified and automized the looming process.

Difference Engine
The difference engine is an automatic mechanical calculator designed to tabulate polynomial functions. It is invented by the Charles Babbage, also known as the father of computing, in 1820s. Its name is derived from the method of divided differences, a way to interpolate or tabulate functions by using a small set of polynomial coefficients.

Analytical Engine
The Analytical Engine was a proposed mechanical general-purpose computer designed by Charles Babbage. It was first annouced as the successor to his difference engine, a design for a simpler mechanical computer, in 1837. It would have worked same as the first modern computer as it has incoporated an airthmetic logical unit (ALU), control unit (CU) and memory (Storage). Though never completed, it inspired a generation of new inventors and scientist to work on computing devices.

Tabulating Machine
The tabulating machine was developed by Herman Hollerith in 1880. It used punched cards with round holes. It can read one card at a time. It was the eletromechanical calculating machine. The Tabulating Machine Company later became International Business Machine (IBM) in 1924.

MARK I
MARK I was the first programmable digital computer. It was developed by the Harvard University staff with funding from IBM. The MARK I project was first proposed by Howard Aiken to IBM in November 1937 and came into realization on 7 August, 1944. It was build on the concept of Charles's Babbage Analytical Machine with few conceptual additions. It was used by the US Navy during World War II. It used magnetic drums for storing the data.

Five Generations of Modern Digital Computers

In terms of computers, a generation refers to the major improvement in computer technology over a period of time. It started when electronic circuits replaced old gears and other mechanical parts used in mechanical machines. In each new generation, circuits became smaller and faster than their previous iteration. This also helped to increase the processing and memory of the computers. As of now, there are 5 generations of computers as described below.

First Generation (1942-1955)
The first generation computers were based on vacuum tubes. They used magnetic drums as storage device. They used Batch Operating System and can perform a calculation in 333 micro seconds. They were mostly used for scietific applications. Some of the first generation computer examples are ENIAC and UNIVAC-I. They produced a lot of heat and were non-portable.

Second Generation (1955-1964)
The second generation computers were based on transistors. They were significantly smaller than first generation computers. They used less energy and not used to generate heat. They had better speed and could calculate data in microseconds. They used time sharing and multitasking operating system. They used faster peripheral devices such as tape drives, magnetic disks and printers. They also ssed Assembly language instead of Machine language. However, a cooling system was still needed. It was still used for specific purposes. They were still costly and not versatile. Some of the popular second generation computers are PDP-8 and IBM 1401.

Third Generation (1964-1975)
The third generation computers were based on integrated circuits (IC). With the advent of IC, computers became smaller in size, faster, more reliable and less expensive. Some of the prime examples of third generation computers are IBM 370, IBM System/360, UNIVAC 1108 and UNIVAC AC 9000 etc. They used real-time operating system and can perform a single task in nano-seconds. They used High Level Languages such as FORTRAN, ALGOL and COBOL. They were specifically used for maintaining databases in public and corporate organisations.

Fourth Generation (1971-1990)
The fourth generation computers are based on VLSI chips. They used semi conductor memories and winchester disk as storage device. Their speed for a task is clocked in pico-seconds. They real time sharing and distributed opearting systems. They used Higher Level Languages such as C, C++, and DBASE. Internet was introduced during this generation and it made computers to reach household.

Fifth Generation (1990 onwards)
The fifth generation of computers are based on ULSI (Ultra Large Scale Integration) Chips which contains millions of ICs embedded in one chip. This generation is based on parallel processing and artificial intelligence. It is uses higher level programming languages such as Java, C++ and PHP. The application of fifth generation computers can be seen in robotics, neural networks, machine translation and so on.