Computer Fundamental

   1.History of Computer.    

The history of computer starts from  4000 years ago. History of computer means the gradual change in the concept over a long period of time. Around fifth century, Hindu philosophers developed a new method of counting from 0 to 9. Counting the numbers from 0 to 9 can be performed with the help of fingers. The development of counting started from the development of simple counting device called ABACUS.

Abacus:

It is the early counting and calculating device that was developed by the Chinese people. The ABACUS was first used for computations in 3000 B.C. It was made of a wooden frame on which there were strings. The frame was divided into two parts, heaven and earth, by a mid-bar. Each string in heaven had two beads each having the value of five units and each string on the earth had five beads each having the value of one unit. During the calculation, the beads were shifted to the mid-bar. It also followed the place value system. It was used to add, subtract, divide and multiply.

Napier's Bones:

In 1614 AD, a Scottish mathematician John Napier discovered the concept of logarithms. In 1617 AD, he constructed a set of rods called Napier Bones fordoing mathematical calculation easily. It consisted of eleven sets of bone rods on which the numbers were engraved. It was used for multiplication. It was based on the principle of performing multiplication by the addition of logarithms.

Slide Rule:

After the invention of logarithm in 1617 AD, William Outghtred invented the Slide Rule in 1620. This device was made on the principle of logarithms. This device consists of two graduated scales, one small and other larger one. One of the scales passes over the other. It was used calculation product and quotient. The calculation was done by sliding the smaller scale over the large scale and the result was obtained by viewing the scales.

The Slice Rule was used by the engineers till 1970. This was replaced by pocket calculator.

Pascal's Calculating/Adding Machine:

It was developed by Blaise Pascal in 1642. It was a mechanical calculator that used toothed wheels and gears. The numbers were written on the wheels and the calculations was done by dialing the numbers. It was also called as Pascaline. It was used to add, subtract. ,multiply and divide.

Leibniz's Calculator:

It was made by a German philosopher Gottrified Wilhem von Leibniz (G.V. Leibniz) in 1671 AD. It was based on Pascal's principle. But it used gears, toothed wheels and drums. It was able to add, subtract and even find square roots. It worked on the principle that multiplication and division can be done by repetitive addition and subtraction of numbers. It was also called as Stepped Reckonor.

Difference Engine:

In 1822 AD, an English mathematician (Professor of Mathematics at Cambridge University) invented a machine called Difference Engine with mechanical memory to store results. It was based on the difference tables of squares of the numbers. Due to which it got its name as Difference Engine.

Analytical Engine:

It was also developed by Charles Babbage in 1830s. It consisted of the input unit for taking data and instructions, mill for performing calculation, memory (punched card) with a suitable output device that was used in giving the final result. It was designed to calculate up to 20 decimal places. The same principles of Analytical Engine is used in the modern computer. So he is called as the "Father of Modern Computer" . Using the principles of Charles Babbage, About 100 years later, Mark-1 was developed by Howard Aiken in 1937.
The analytical Engine was never completed due to the lack of techniques and technology because of which he was unable to get the parts that he wanted in his machine.

Lady Augusta Ada Lovelace:

One of the great supporters of Charles Babbage was lady Augusta Ada (The daugher of Famous poet, lord Byron). She convinced Babbage to use binary concept in his Analytical Engine. She wrote different types of programs that were used in the Babbage machines. So she is remembered as the "First Programmer" in the history of computer science and has to her credit a computer language called ADA named after her.

Dr. Herman Hollerith:

He was the first person to use punched card practically on his Census Tabulating Machine in 1880s. The information is stored as holes in cards, which are interpreted by machines with electrical sensors. The cards were punched by a machine called Punched Card Machine or Hollerith's Tabulating Machine. Then he established Tabulating Machine Company to sell his products. Later, when other companies merged with TMC, new company were established under the name International Business Machine Company and he came the founder of IBM. It is the worlds leading computer manufacturer.


Mark-1 (Howard Aiken):

In the late 1930s, next important event was added in the history of computer; the electromechanical computer was born with the development of MARK-1 in 1944 by Howard Aiken with the help of IBM. It also used the punched cards designed for Difference Engine. It was 51 ft long, 8 ft high and 13 ft wide. It used large numbers of valves, switches and resistors. It was used to produce ballistics tables in 2nd world war.

Electronic Numerical Integrator and Calculator (ENIAC):

It is the first electronic computer that was developed by john Mouchlay and J. Prisper Eckert in 1947. It was based on the decimal number system. 18,000 vacuum tubes were used in ENIAC. There were 70,000 resistors, 10,000 condensers and 6,000 switches. It weighed 30 tones and occupied a space 3,000 cubic feet. It could calculates 300 times faster than any calculating devices at that time and it was based on decimal number.


Electronic Discrete Variable Automatic Computer (EDVAC):

In 1949, the first electronic computer was developed by John Mauchly and John Presper Eckert with the help of A. Burks, Goldstine and Neumann. This machine was used to store the data and information as well as the instructions. This computer operated electronically.

UNIVAC-I (Universal Accounting Computer):
John Mauchly and Eckert founded their own company in 1946 and began to work on the Universal Automatic Computer (UNIVAC): general-purpose commercial computer in 1951. It was the first commercially used electronic computer in the world.

# In 1977, Steve Wozniak and Stave Jobs establish the company Apple computers.
# In 1984, Apple introduces the Macintosh, the first widely available computer with a  "user-friendly"               graphical interface using icons, windows, and a mouse device.
# In 1989, Microsoft Corporation introduces Windows for IBM Computers.

2.Generation of computer.

Depending on the device used, system architecture, processing mode and language used in the computers are categorized in the following five generation. The development of different types of memory devices has given a sequence of development of computers from mainframe to mirocomputers. In the development of computers there is lot of change from 1946 to 1990. This time is divided in different generations by scientists in a conference in 1962.

First Generation (1946 to 1954):

Introduction of the UNIVAC I in 1951 marked the beginning of the first generation. They began to work on the Universal Automatic Computer (UNIVAC) in 1946; so we can considered the duration of first Generation starts from 1946. The computers using vacuum tubes as a memory unit are known as first-generation computers. The vacuum tube consumes a lot of power. The Vacuum tube was developed by Lee DeForest In 1908.

Features:
1.     They used valves or vacumm tubes as their main electronic component.
2.     They were large in size, slow in processing and had less storge capacity.
3.     They consumed lots of electricity and produced lots of heat.
4.     Their were not so accurate and reliable.
5.     They used machine level language for programming.
6.     They were very expensive.
7.     Their computing capabilities were limited.
Example: ENIAC, UNIVAC, IBM 650 etc.

Second Generaton (1955 to 1964):

The invention of Semi-conductor transistor had made big revolution in the field of computer. The transistor replaced the Vacuum tube. The second-geration computers used transistor as a memroy unit. A transistor could do the work of 1000 vacuum tubes. Second generation computers are smaller in size. They are more reliable and faster than the first generation computers. Assembly language was used for programming in second-generation computers.

Features:
1. Transistors were used instead of Vacuum Tube.
2. Processing speed is faster than first Generation Computers (Micro Second)
3. Smaller in size (51 square feet).
4. The input and output devices were faster.
Example: IBM 1400 and 7000 Series, Control Data 3600 etc.

Third Generation (1965 to 1947):

By the development of a small consisting of the capacity of the 300 transistors called Integrated Chip (IC). The computers, using ICs are of the third Generatiions . Thy were smaller in size and had higher efficiency in speed and memory capacity. Very soon ICs were replaced by LSI (large Scale Integration), which consisted about 100 components. An IC containing about 100 components is called LSI.

Features:
1. They used Integrated Circuit (IC) chips in place of the transistors.
2.  Semi conductor memory devices were used.
3.    The size was greatly reduced, the speed of processing was high, they were more accurate and reliable.
4. Large Scale Integration (LSI) and Very Large Scale Integration (VLSI) were also developed.
5. The mini computers were introduced in this generation.
6. They used high level language for programming.
Exmaple: IBM 360, IBM 370 etc.

Fourth Generation (1975 to 1990):

An IC containing about 100 components is called LSI ( Large Scale Integration) and teh one, which has more than 1000 such components, is called as VLSI (Very Large Scale Integration). The computers designed using VLSI, as a memory unit is known as fourth Generation computers. The first microprocessor 8008 was developed by American Compahy (Intel Corporation) in 1971 and in 1974; another more powerful microprocessor 8080 was developed. The microprocessor 8080 was used in early XT computers. Microprocessor based computers fall in fourth generation computer group. VLSI is also called as microprocessor.

features:
1. They used Microprocessor (VLSI) as their main switching element.
2. They are also called as micro computers or personal computers.
3. Their size varies from desktip to laptop or palmtop.
4.    They have very high speed of processing; they are 100% accurate, reliable, diligent
       and versatile.
5. They have very large storage capacity.
Example: IBM PC, Apple-Macintosh etc.

Fifth Generation (1990-Present and Future):

The fifth-generation computers are under development stage. These computers are being made using microprocessor and will use USLI (Ultra-large-scale integration) chips (BIO-Chips) in the future. Such computers will use intelligent programmingand improved human-machine interfaces. It is estimated that these computers of fifth generation will have an Artificial Intelligence (AI) with a little thinking capacity and they will understand the natural languages like English, Japanese etc.

Features:
1. They are the future computers which will use parallel processor or genetically
    engineered bio-chips as their main switching element.
2. They will have Artificial Intelligence (AI) and will be able to understand natural
     language.
3. They will have extremely high efficiency and reliability.

3.Classification of computer. 

Computers can be classified into classes according to their following factors.

1. On the basis of Working Principle

a) Analog Computer

Analog computer measures continuous          types of data and uses a physical quantity like, electric current, voltage, temperature etc. to present and process the data. We have seen many Analog devices in our life. It represent numbers by a physical quantity; that is , they assign numeric values by physically measuring some actual property, such as the length of  an object, an angle created by two lines, or the amount of voltage passing through a point in an electric circuit. Thermometer, Multimeter, Speedometer, Fuel and Price Indicator in Petrol Pump are the examples of Analog devices. They are special purpose computers.

b) Digital Computer

The computer which accepts discrete data (discontinuous data) as per the electric signals is known as digital computer. Basically, digital computer counts digits, which represent numbers or letters. They are the most widely used type of computers. The computers based on binary digits i.e. 0 1 are called digital computer. It represents each and every information (number, letter and other special symbols) in terms of single numbers (0 and 1) and processes these information by using standard arithmetic operations. 90% of the computers are digital computers. They are general purpose computers.


c) Hybrid Computer (Analog+Digital)

 

                                                                                                                         Hybrid computer is the combination of the features of Analog and Digital computers. It has both features of Analog and Digital computer. It can do all types of Tasks of Digital and Analog. They are mostly used in scientific research, industrial application, aeroplanes etc. They are special purpose computer.

2. On the basis of size

            a) Mainframe Computer

                        Mainframe computers are large computers which processes at high speed and occupies a large space. This has a large capacity to handle huge numbers of records. More than 100 people can work at a time and communicate with different countries with Wide Area Networks via satellite. They are generally used in large scale organizations and government officers for large –scale data processing. Such computers can be seen in the Universities, Institute of Engineering, and Scientific research centers.

                                       Mainframe Computer

In one word, a large computer, usually designed to serve a number of remote terminals is called Mainframe Computer.

            b) Mini computer                 

Mini computer

Mini computers are medium in size than Mainframe computers but larger than microcomputers. They are less powerful than super and Mainframe but more powerful than micro computers. They are specially used in data processing, Programming, Desktop publishing fields. In other words, a computer smaller than a mainframe and larger than a microcomputer, intended to support multiple users is called Mini computer

 c) Micro Computer

                        Micro computer is also known as Personal Computer or Home Computer. They are made by using microprocessor. They are widely used at homes and officers. Many brands models and sizes are available in microcomputers. They are used in many fields of business, education , desktop & graphic designing, data processing etc.

                        In other words, a small computer driven by a single integrated circuit and designed for use by     one person is called microcomputer. It is also called PC.

     Microcomputers can be sub categorized into:

                        i.     Desktop Computer: a personal or micro-mini computer sufficient to

                               fit on a desk.

                        ii. Laptop computer: a portable computer complete with an integrated screen and keyboard.            
          It is generally smaller in size than a desktop computer and larger than a notebook computer.

Laptop with Touch Scree



                                                                                                                                                                                                                                 Laptop with track ball

                        iii. Palmtop Computer/Digital Diary/Notebook: a hand-sized computer. Palmtops have no                             keyboard but the screen serves both as an input and output device.

            d) Super Computer

                        A computer that is capable of working at very great speed, and can thus processes a very large amount of data within an acceptable time. Super computers are used in designing complicated machines as supersonic jets, space research, and picture composition for movie films, and for weather forecasting. Super Computers have the largest, fastest and most expensive systems in the world.

            CRAY-I/II/III, CYBER-205, HITACHI-810/20 are some popular Super Computes.

        CRAY-I Super Computer

3. On the basis of Brand

            a) IBM PC

                        The computes manufactured by IBM ( International Business Machine) company are called IBM Computers. The microcomputers of IBM Company are called IBM PC. IBM is one of the leading company in computer industry.

            b) IBM Compatible

                        Computers, developed on the principles of IBM Computers are called IBM Compatible. It can perform all the tasks that a IBM computers does. They are less expensive than original (IBM) computers.

In other words, a personal computer that is compatible with the IBM PC is called IBM Compatible Computer.

c) Apple/Macintosh

            The computers manufactured by the Apple Company are called Apple Computers. They are specially used in Desktop-Designing. They are quite expensive than IBM and IMB Compatible.

            The Operating System and other peripherals are completely different than IBM and IBM Compatibles.