The computers of today are vastly different in appearance and performance as compared to the computers of earlier days. But where did this technology come from and Where is it heading? To fully understand the impact of computers on today’s world and the promises they hold for the future, it is important to understand the evolution of computers.
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1.2.1. The First Generation:
The first generation computers made use of:
- Vacuum tube technology,
- Punched cards for data input,
- Punched cards and paper tape for output,
- Machine Language for writing programs,
- Magnetic tapes and drums for external storage.
The computers of the first generation were very bulky and emitted large amount of heat which required air conditioning.
- They were large in size and cumbersome to handle.
- They had to be manually assembled and had limited commercial use.
- The Concept of operating systems was not known at that time.
- Each computer had a different binary coded program called a machine language that told it how to ooperate
The Abacus, which emerged about 5000 years ago inAsia Minor and is still in use
today, allows users to make computations using a system of sliding beads arranged on a rack. Early merchants used Abacus to keep trading transactions.
Blaise Pascal, a French mathematician invented the first mechanical
machine, a rectangular brass box, called Pascaline which could perform addition and
subtraction on whole numbers. This was in the seventeenth century. Colmar, a
Frenchman invented a machine that could perform the four basic arithmetic functions of addition, subtraction, multiplication and division. Colmar’s mechanical calculator,
“Arithmometer”, presented a more practical approach to computing. With its
enhanced versatility, the “Arithmometer” was widely used until the First World War,
although later inventors refined Colmar’s calculator, together with fellow inventors, Pascal and Leibniz, he helped define the age of mechanical computation
Charles Babbage a British mathematician at Cambridge University invented the first analytical engine or difference engine. This machine could be programmed by instructions coded on punch cards and had mechanical memory to store the results. For his contributions in this field Charles Babbage is known as ‘the father of modern digital computer.
Some of the early computers included:
Mark I – This was the first fully automatic calculating machine. It was designed by Howard Aiken of Harvard University in collaboration with IBM. This machine was an electronic relay computer. Electromagnetic signals were used for the movement of mechanical parts. Mark I could perform the basic arithmetic and complex equations. Although this machine was extremely reliable, it was very slow (it took about 3-5 seconds per calculation) and was complex in design and large in size.
Atanasoff-Berry Computer(ABC) –This computer developed by John Atanasoff and Clifford Berry was the world’s
first general purpose electronic digital computer. It made use of vacuum tubes for internallogic and capacitors for storage.
ENIAC (Electronic Numeric Integrator and Calculator) – The first all electronic computer was produced by a partnership between the US Government and the University of Pennsylvania. It was built using 18,000 vacuum tubes, 70,000 resistors and 1,500 relays and consumed 160 kilowatts of electrical power. The ENIAC computed at speed about thousand times faster than Mark I. However, it could store and manipulate only a limited amount of data. Program modifications and
detecting errors were also difficult.
EDVAC – In the mid 1940’s Dr. John von Neumann designed the Electronic Discrete
Variable Automatic Computer with a memory to store both program and data. This was the first machine which used the stored program concept. It had five distinct units - arithmetic, central control, memory, input and output. The key element was the central control. All the functions of the computer were co-ordinate through this single source, thecentral control. The programming of the computers was done in machine
UNIVAC • I – Remington Rand designed this computer specifically for business data
processing applications. The Universal Automatic Computer was the first general
purpose commercially available computer.
The Second Generation:
In the second generation computers:
- Vacuum tube technology was replaced by transistorized technology,
- Size of the computers started reducing,
- Assembly language started being used in place of machine language,
- Concept of stored program emerged,
- High level languages were invented.
This was the generation of Transistorized Computers.
- Vacuum tubes were replaced by transistors.
- As a result, the size of the machines started shrinking.
- These computers were smaller, faster, more reliable and more energy efficient.
advantage of the transistor technology were the early supercomputers, Stretch by IBM
and LARC by Sperry Rand. These machines were mainly developed for atomic energy
laboratories. Typical computers of the second generation were the IBM 1400 and 7000 series, Honeywell 200 and General Electric.
IBM 1401 was universally accepted throughout the industry and most
large businesses routinely processed financial information using second generation computers. The machine language was replaced by assembly language. Thus the long and difficult binary code was replaced with abbreviated programming code which was relatively easy to understand.
The stored program concept and programming languages gave the
computers flexi bility to finally be cost effective and productive for business use. The stored program concept implied that the instructions to run a computer for a specific
task were held inside the computer’s memory and could quickly be modified or replaced by a different set of instructions for a different function. High level languages
like COBOL, FORTRAN and AL- GOL were dev eloped. Computers started finding vast
and varied applications. The entire software industry began with the second generation
computers.
The Third Generation:
The third generation computers were characterized by:
- Use of Integrated circuits,
- Phenomenal increase in computation speed
- Substantial reduction in size and power consumption of the machines
- Use of magnetic tapes and drums for external storage
- Design-of Operating systems and new higher level languages,
- Commercial production of computers.
This generation was characterized by the invention of Integrated Circuits (ICs).
The IC combined electronic components onto a small chip which was made from
quartz.
- Later, even more components were fitted onto a single chip, called a semiconductor. This reduced the size even further. The weight and power consumption of computers decreased and the speed increased tremendously. Heavy emphasis was given to the development of software.
- Operating systems were designed which allowed the machine to run many different programs at once.
- A central program monitored and co-ordinate the computers memory.
- Multiprogramming was made possible, whereby the machine could perform several jobs at the same time.
- Computers achieved speeds of executing millions of instructions per second.
- Commercial production became easier and cheaper.
- Higher level languages like Pascal and Report Program Generator (RPG) were introduced and applications oriented languages like FORTRAN, COBOL, and PL/1 were developed.
The Fourth Generation:
The general features of the fourth generation computers were:
- Use of Very Large Scale Integration,
- Invention of microcomputers,
- Introduction of Personal Computers,
- Networking,
- Fourth Generation Languages.
The third generation computers made use of ‘Integrated Circuits that had 10-20 components on each chip, this was Small Scale Integration (SSI).
The Fourth Generation realized Large Scale Integration (LSI) which could fit hundreds of components on one chip and Very Large Scale integration (VLSI) which squeezed thousand of components on one chip. The Intel 4004 chip, located all the components of a computer (central processing unit, memory, input and output controls) on a single chip and microcomputers were introduced. Higher capacity storage media like magnetic disks were developed. Fourth generation languages emerged and applications software’s started becoming popular.
Computer production became inexpensive and the era of Personal Computers (PCs) commenced. In 1981, IBM introduced its personal computer for use in office, home and schools. In direct competition, the Macintosh was introduced by Apple in 1984. Shared interactive systems and user friendly environments were the features of these computers.
As the computers started becoming more and more powerful, they could be
linked together or networked to share not only data but also memory space and
software. The networks could reach enormous proportionswith local area networks.Aglobalweb of computer circuitry, the Internet, links the computers worldwide into a singl
e network of information.
Defining the fifth generation computers is somewhat difficult because the field is still in its infancy. The computers of tomorrow would be characterized by Artificial
Intelligence (At). An example of Al is Expert Systems. Computers could be developed
which could think and reason in much the same way as humans. Computers would be
able to accept spoken words as input (voice recognition).
Many advances in the science of computer design and technology are coming together to enable the creation of fifth generation computers. Two such advances are parallel processing where many CPUs work as one and advancein superconductor technology which allows the flow of electricity with little or no resistance, greatly improving the speed of information flow.