ASSIGNMENT # 7

HISTORY OF COMPUTERS

            The first computers were people! That is, electronic computers (and the earlier mechanical computers) were given this name because they performed the work that had previously been assigned to people. "Computer" was originally a job title: it was used to describe those human beings (predominantly women) whose job it was to perform the repetitive calculations required to compute such things as navigational tables, tide charts, and planetary positions for astronomical almanacs. Imagine you had a job where hour after hour, day after day, you were to do nothing but compute multiplications. Boredom would quickly set in, leading to carelessness, leading to mistakes. And even on your best days you wouldn't be producing answers very fast. Therefore, inventors have been searching for hundreds of years for a way to mechanize (that is, find a mechanism that can perform) this task.

MANUAL COMPUTING DEVICES

ABACUS (around 500 B.C.) - Considered as the earliest device for calculation, the abacus is used by Europeans, Chinese and Japanese for simple addition, subtraction, multiplication and division. It is made up of a wooden frame divided into two parts by a beam. On its upper part is a deck of two rows of beads. A series of vertical rods allow the beads to slide.

NAPIER'S BONE (1617) - Names after its inventor, Scottish Mathematician John Napier, this tool is made up of multiplication tables inscribed in a wood or bone.

SLIDE RULE (1620) - Invented by William Oughtred, this is a single straight two-foot long ruler plotted with a logarithmic scale. Multiplication and division are done by using a pair of dividers.


 MANUAL MECHANICAL CALCULATORS

PASCALINE OR PASCAL'S ADDING MACHINE (1642) - The machine was the first operational calculating machine that could add large numbers. It was invented by Blaise Pascal, a French mathematician.

STEP RECKONER (1670) - Gottfried von Leibnitz, a German baron, improved the Pascaline into a device that could add, subtract, multiply, divide and get square roots.

DIFFERENCE ENGINE (1822) - Charles Babbage was a British mathematician and inventor who built a machine that automatically calculated mathematical tables, such as logarithmic and trigonometric tables. He called this machine a "computer". 

ANALYTICAL ENGINE (1830) - This was also invented by Charles Babbage. Compared to the difference engine, the analytical engine was not only able to perform calculations but also to store data in the memory and perform logical comparison.


ELECTROMECHANICAL COMPUTER

 HOLLERITH'S TABULATING MACHINE (1890) - Invented by the American inventor Herman Hollerith, this machine was capable of representing, reading and assembling data.

ELECTRONIC COMPUTERS

MARK 1 - Invented by DR. Howard Aiken, it is the first operating machine that could perform long computations automatically. It could execute addition and subtraction in a second, multiplication in six seconds, division in 15.3 seconds and logarithm and trigonometric functions in over one minute.

ENIAC OR ELECTRONIC NUMERICAL INTEGRATOR AND COMPUTER (1946) - Developed by John Mauchly and J Presper Eckert, it was the first general purpose electronic computer which was made up of vacuum tubes. It was used to process one problem at a time. 

UNIVAC 1 OR UNIVERSAL AUTOMATIC COMPUTER (1951) - It is the first commercially available computer that could perform about 1,905 operations per second running on a 2.25 Megahertz clock. The complete system occupied more than 35.5 m2 of the floor space. 

GENERATIONS OF COMPUTERS 


Fourth-generation computers - These computers are much smaller, faster and more powerful than the earlier models. The use of microprocessors make them more multi-functional. Consist of million of transistors, they can do millions of calculations per second.


Third-generation computers - Called minicomputers, these computers were compact, reliable, and less expensive. Instead of transistors, they use integrated circuits (ICs) or chips which are much smaller compared to transistors. 


Second-generation computers - Unlike the first-generation computers, which used vacuum tubes, these computers used transistors which are smaller, more efficient, and less-energy consuming.

First-generation computers -  These computers were bulky, took up large spaces, and needed to be kept in cool environment. They used wired circuits that had thousands of vacuum tubes, each of which was about the size of a light bulb.

Types of Computers

The types of computers range from the Hybrid to the Analog types. The computers you come across in the daily course of your day range from laptops, palmtops and towers, to desktop computers, to name a few. But the very word “computers” reminds one of the desktop computers used in offices or homes. Different categories of computes have been devised in keeping with our varied needs.

 

    

    The Types Of Computers: Analog and Hybrid (classification based on operational principle)

• Analog Computers: The analog computer is almost an extinct type of computer these days. It is different from a digital computer in respect that it can perform numerous mathematical operations simultaneously. It is also unique in terms of operation as it utilizes continuous variables for the purpose of mathematical computation. It utilizes mechanical, hydraulic, or electrical energy or operation.
• Hybrid computers: These types of computers are, as the name suggests, a combination of both Analog and Digital computers. The Digital computers which work on the principle of binary digit system of “0” and “1” can give very precise results. But the problem is that they are too slow and incapable of large scale mathematical operation. In the hybrid types of computers the Digital counterparts convert the analog signals to perform Robotics and Process control.

Apart from this, computers are also categorized on the basis of physical structures and the purpose of their use. Based on Capacity, speed and reliability they can be divided into three categories of computers:

1. The Mainframe Computer – These are computers used by large organizations like meteorological surveys and statistical institutes for performing bulk mathematical computations. They are core computers which are used for desktop functions of over one hundred people simultaneously.

2. The Microcomputer – These are the most frequently used computers better known by the name of “Personal computers”. This is the type of computer meant for public use. Other than Desktop Computer the choice ranges as follows:

• Personal Digital Computer
• Tablet PC
• Towers
• Work Stations
• Laptops
• Hand Held Computer

3. The Mini computer – Mini computers like the mainframe computers are used by business organization. The difference being that it can support the simultaneous working of up to 100 users and is usually maintained in business organizations for the maintenance of accounts and finances.

Yet another category of computer is the Super Computers. It is somewhat similar to mainframe computers and is used in economic forecasts and engineering designs. Today life without computers is inconceivable. Usage of different types of computers has made life both smooth and fast paced.

Source: ICT book 

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