Introduction

The human race developed computers so that it could perform intricate operations, such as calculation and data processing, or simply for entertainment. Today, much of the world’s infrastructure runs on computers and it has profoundly changed our lives, mostly for the better. Let us discuss some of the characteristics of computers, which make them an essential part of every emerging technology and such a desirable tool in human development.

1. Speed: The computers process data at an extremely fast rate, at millions or billions of instructions per second. A computer can perform a huge task in a few seconds that otherwise a normal human being may take days or even years to complete.The speed of a computer is calculated in MHz (Megahertz), that is, one million instructions per second. At present, a powerful computer can perform billions of operations in just one second.
2. Accuracy: Besides the efficiency, the computers are also very accurate.The level of accuracy depends on the instructions and the type of machines being used.Since the computer is capable of doing only what it is instructed to do,faulty instructions for data processing may lead to faulty results.This is known as GIGO (Garbage In Garbage Out).
3. Diligence: Computer, being a machine, does not suffer from the human traits of tiredness and lack of concentration. If four million calculations have to be performed, then the computer will perform the last, four-millionth calculation with the same accuracy and speed as the first calculation.
4. Reliability: Generally, reliability is the measurement of the performance of a computer, which is measured against some predetermined standard for operation without any failure. The major reason behind the reliability of computers is that, at hardware level, it does not require any human intervention between its processing operations. Moreover, computers have built-in diagnostic capabilities,which help in continuous monitoring of the system.
5. Storage Capability: Computers can store large amounts of data and can recall the required information almost instantaneously. The main memory of the computer is relatively small and it can hold only a certain amount of data, therefore, the data is stored on secondary storage devices such as magnetic tape or disks. Small sections of data can be accessed very quickly from these storage devices and brought into the main memory, as and when required, for processing.
6. Versatility: Computers are quite versatile in nature. It can perform multiple tasks simultaneously with equal ease. For example, at one moment it can be used to draft a letter, another moment it can be used to play music and in between, one can print a document as well. All this work is possible by changing the program (computer instructions).
7. Resource Sharing: In the initial stages of development, computers used to be isolated machines.With the tremendous growth in computer technologies, computers today have the capability to connect with each other. This has made the sharing of costly resources like printers possible. Apart from device sharing, data and information can also be shared among groups of computers, thus creating a large information and knowledge base.

Although processing has become less tedious with the development of computers, it is still time-consuming and expensive job. Sometimes, a program works properly for some period and then suddenly produces an error. This happens because of a rare combination of events or due to an error in the instruction provided by the user. Therefore, computer parts require regular checking and maintenance in order to give correct results. Furthermore, computers need to be installed in a dust free place. Generally, some parts of computers get heated up due to heavy processing. Therefore, the ambient temperature of the computer system should be maintained.

THINGS TO REMEMBER

Limitations of a Computer

Sand Tables

In ancient times, people used fingers to perform the calculations such as addition and subtraction. Even today,simple calculations are done on fingers. Soon, mankind realised that it would be easier to do calculations with pebbles as compared to fingers. Consequently, pebbles were used to represent numbers, which led to the development of sand tables. They are known to be the earliest device for computation.

A sand table consists of three grooves in the sand with a maximum of 10 pebbles in each groove. To increase the count by one, a pebble has to be added in the right hand groove. When ten pebbles were collected in the right groove, they were removed and one pebble was added to the adjacent left groove. Afterward, sand tables were modified extensively and these modifications resulted in a device known as Abacus.You can see the below image of abacus.

 

Abacus

Abacus emerged around 5000 years ago in Asia Minor and in some parts of the world it is still in use.The word ‘abacus’ was derived from Arabic word ‘abaq’ which means ‘dust’. The first abacus was simply a portable sand table; a board with dust strung across it. An abacus consists of a wooden frame,which has two parts: upper and lower. The upper part contains two beads and lower part contains five beads per wire. A raised bead in upper denotes 0 whereas a lowered bead denotes digit 5. In the lower part, a raised bead stands for 1 and a lowered bead for 0. This device allows users to do computations using a system of sliding beads arranged on a rack. Manipulating the beads on the wires carry out arithmetic operations.

Napier Bones

In 1614, a Scottish mathematician, John Napier, made a more sophisticated computing machine called Napier bones. This was a small instrument made of 10 rods, on which the multiplication table was engraved. It was made of strips of ivory bones, and so the name Napier bones.This device enabled multiplication in a fast manner, if one of the numbers was of one digit only (for example,6 × 6745). Incidentally, Napier also played a key role in the development of logarithms, which stimulated the invention of ‘slide rule’ that substituted the addition of logarithms for multiplication. This was a remarkable invention as it enabled the transformation of multiplication and division into simple addition and subtraction.

Slide Rule

The invention of logarithms influenced the development of another famous invention known as slide rule. In AD 1620, the first slide rule came into existence. It was jointly devised by two British mathematicians, Edmund Gunter and William Oughtred. It was based on the principle that actual distances from the starting point of the rule is directly proportional to the logarithm of the numbers printed on the rule. The slide rule is embodied by two sets of scales that are joined together, with a marginal space between them. This space is enough for the free movement of the slide in the groove of the rule.

The suitable alliance of two scales enabled the slide rule to perform multiplication and division by a method of addition and subtraction.

Pascaline

In 1623, Wilhelm Schickard invented the ‘calculating clock’,which could add and subtract, and indicated the overflow by ringing a bell. Subsequently, it helped in the evolution of Pascaline. In AD 1642, French mathematician,scientist and philosopher, Blaise Pascal, invented the first functional automatic calculator. It had a complex arrangement of wheels, gears, and windows for the display of numbers. It was operated by a series of dials attached to wheels that had the numbers zero to nine on their circumference.When a wheel made a complete turn, it advanced to the wheel to the left of it. Indicators above the dial displayed the correct answer. However, usage of this device was limited to addition and subtraction only.

Stepped Reckoner

In 1694, German mathematician Gottfried Wilhem Von Leibriz extended the Pascal’s design to perform multiplication, division, and to find square root.This machine is known as stepped reckoner. It was the first mass-produced calculating device, which was designed to perform multiplication by repeated addition. The stepped reckoner did not make use of interconnected gears, but instead, a cylinder of stepped teeth operated it. The only problem with this device was that it lacked mechanical precision in its construction and was not very reliable.

Punch Card System

Joseph Marie Jacquard, a French textile weaver, used the principle of the weaving process to represent the two digits of the binary system. Jacquard took a large step in the development of computers when he developed punch cards to increase rug production. In 1801,Jacquard invented a power loom with an automatic card reader known as punch card machine. The idea of Jacquard to use punched cards was to provide an effective means of communication with machines. He automated the process with the use of punched cards and placed them between the needles and the thread. The presence or absence of a hole represented the two digits of the binary system, which is the base for all modern digital computers.

 

Difference Engine

Charles Babbage, a professor of mathematics, devised a calculating machine known as the difference engine in 1822, which could be used to mechanically generate mathematical tables.The difference engine can be viewed as a hugely complex abacus. It was intended to solve differential equations as well.However, Babbage never quite made a fully functional difference engine and in 1833, he quit working on this machine to concentrate on the analytical engine.

Analytical Engine

Analytical engine is considered to be the first general-purpose programmable computer. Babbage’s innovation in the design of the analytical engine made it possible to test the sign of a computed number and take one course of action if the sign was positive, and another if the sign was negative.Babbage also designed this device to advance or reverse the flow of punched cards to permit branching to any desired instruction within a program. This was the fundamental difference between the analytical engine and the difference engine. Lady Ada Lovelace helped him in the development of the analytical engine.She not only helped Babbage with financial aid, but being a good mathematician, also wrote articles and programs for the proposed machine. Due to her contributions, she is known as the ‘first programmer’.However, Babbage never completed the analytical engine, but his proposal for this device reviewed the basic elements of the modern computer such as input/output, storage, processor, and control unit.

Hollerith’s Tabulator

Herman Hollerith invented the punched-card tabulating machine to process the data collected in the United States’ census. This electronic machine was able to read the information on the cards and process it electronically. It consisted of a tabulator, a sorter with compartments electronically controlled by the tabulator’s counter and the device used to punch data onto cards. This tabulator could read the presence or absence of holes in the cards by using spring mounted nails that passed through the holes to make electrical connections. In 1896, Hollerith founded the Tabulating Machine Company, which was later named IBM (International Business Machines).

Other Developments

In the process of the development of computers, many scientists and engineers made significant advances.

1.In 1904, Sir John Ambrose Fleming worked to develop the first thermionic valve, also known as vacuum tube. Thermionic valves were based on Thomas Edison’s ‘Edison effect’ of light bulbs. The first light bulbs were very shortlived and were prone to darken. This darkening was termed the Edison effect. Sir John Ambrose Fleming worked to develop the first rectifier and in 1904, he developed thermionic valves. Fleming named the device a valve because it allowed electrical currents to pass only in one direction. Since this is a two-element vacuum tube, it was also called as diode. These diodes were the cornerstone of the first generation computers.

2.In 1906, an American inventor, Lee de Forest introduced a third electrode into the diode (vacuum tube). The resulting triode could be used both as an amplifier and a switch and because of their ability to act as a switch created a tremendous impact on digital computing.

3.In 1931, an American electrical engineer, Vannevar Bush, built the differential analyzer to solve differential equations. Nevertheless, the machine was cumbersome because this device used its drive belts, shafts, and gears to measure movements and distances.

4.In 1938, Claude Shannon, a student at MIT, recognised the connection between electronic circuits and Boolean algebra. He transferred the two logic states to electronic circuits by assigning different voltage levels to each state. Shannon also provided electronic engineers with the mathematical tool they needed to design digital electronic circuits. These techniques remain the cornerstone of digital electronic design to this day.

Conclusion

It is crucial for understanding computers, features are the key to appreciating how our lives change with them. Their characteristics include speed, precision of work, size of storage memory, automation level, multitasking ability and universality as well as their connectivity and scalability that makes computers irreplaceable in the contemporary world. These features will only evolve as technology does, allowing computers to handle even more sophisticated operations and, in turn, defining life in the 21st century.