Computer Fundamentals Chapter 3 PDF

Chapter Three Computer Fundamentals 1. EVOLUTION OF COMPUTERS 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...

Chapter Three Computer Fundamentals 1. EVOLUTION OF COMPUTERS 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. 1.1. 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 operate. Punched cards Paper tape Vacuum tube Fig. 1.1 The first Generation Computer technology The Abacus, which emerged about 5000 years ago in Asia 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.  Abacus Pascaline Fig. 1.2 the first Generation Computers 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. Introduction to Computer System /3 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 internal logic 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. Fig. 1.3 ENIAC 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, the central control. The programming of the computers was done in machine language UNIVAC I – Remington Rand designed this computer specifically for business data processing applications. The Universal Automatic Computer was the first general Fig 1.4 UNIVAC Computer Fundamentals purpose commercially available computer. 1.2 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. The first transistorized computer was TX-0. The first large scale machines that took 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. Fig 1.5 Transistors 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. 1. 3. 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, Fig 1.6 i) Integrated Circuit ii) Integrated Circuit Commercial production of computers. This generation was characterized by the invention of Integrated Circuits (ICs). The 1C 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 computer s 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. 1. 4. 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.  Fig. 1.7 VLSI The third generation computers made use of ‘Integrated Circuits that had 1020 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 proportions with local area networks. A global web of computer circuitry, the Internet, links the computers worldwide into a single network of information. 1. 5 The Fifth Generation: 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 advance in superconductor technology which allows the flow of electricity with little or no resistance, greatly improving the speed of information flow. Check your Progress -1.2 1. Match the following. A B a) Very Large scale Integration I) Second Generation b) Vacuum Tube Technology II) Fifth Generation c) Stored Program III) Fourth Generation d) Superconductor Technology IV) First Generation e) Semiconductor Technology v) Third Generation 2. Write True or False A. Expert system is an example of artificial Intelligence. B. The world’s first general purposes electronic digital computer was the Abacus. C. The first generation computers used machine language for programming. D. Charles Babbage designed the Analytical Engine. E. Personal Computer (PC) was developed in the first generations. 1. 2 CLASSIFICATION OF COMPUTERS Computers are broadly classified into two categories depending upon the logic used in their design as: Analog computers: In analog computers, data is recognized as a continuous measurement of a physical property like voltage, speed, pressure etc. Readings on a dial or graphs are obtained as the output, ex. Voltage, temperature; pressure can be measured in this way. Digital Computers: These are high speed electronic devices. These devices are programmable. They process data by way of mathematical calculations, comparison, sorting etc. They accept input and produce output as discrete signals representing high (on) or low (off) voltage state of electricity. Numbers, alphabets, symbols are all represented as a series of 1s and Os. Digital Computers are further classified as General Purpose Digital Computers and Special Purpose Digital Computers. General Purpose computers can be used for any applications like accounts, payroll, data processing etc. Special purpose computers are used for a specific job like those used in automobiles, microwaves etc. Another classification of digital computers is done on the basis of their capacity to access memory and size like: Small Computers: I) Microcomputers: Microcomputers are generally referred to as Personal Computers (PCs). They have Smallest memory and less power. They are widely used in day to day applications like office automation, and professional applications, ex. PCAT, Pentium etc. II) Note Book and Laptop Computers: These are portable in nature and are battery operated. Storage devices like CDs, floppies etc. and output devices like printers can be connected to these computers. Notebook computers are smaller in physical size than lap top computers. However, both have powerful processors, support graphics, and can accept mouse driven input.  Microcomputer Notebook or Laptop Handheld Computer Fig. 1.8 Small Computers Hand Held Computers: These types of computers are mainly used in applications like collection of field data. They are even smaller than the note book computers. Hybrid Computers: Hybrid Computers are a combination of Analog and Digital computers. They combine the speed of analog computers and accuracy of digital computers. They are mostly used in specialized applications where the input data is in an analog form i.e. measurement. This is converted into digital form for further processing. The computers accept data from sensors and produce output using conventional input/output devices. Mini Computers: Mini computers are more powerful than the micro computers. They have higher memory capacity and more storage capacity with higher speeds. These computers are mainly used in process control systems. They are mainly used in applications like payrolls, financial accounting, Computer aided design etc. ex. VAX, PDP-11  Mainframe Computers: Main frame computers are very large computers which process data at very high speeds of the order of several million instructions per second. They can be linked into a network with smaller computers, micro computers and with each other. They are typically used in large organizations, government departments etc. ex. IBM4381, CDC Super Computers: A super computer is the fastest, most powerful and most expensive computer which is used for complex tasks that require a lot of computational power. Super computers have multiple processors which process multiple instructions at the same time. This is known as parallel processing. These computers are widely used in very advanced applications like weather forecasting, processing geological data etc. ex. CRAY-2, NEC - 500, PARAM. Check your Progress - 1.2 1. Fill in the blanks a. Personal computers are also called as …………………. b. Combination of Analog and Digital computers are called as …………….. c. In a ………..computer number and characters are represented as a series of 0’s and 1’s. 2. Answer in brief 1. What is parallel processing?.................................................................................................................................................................................................................................................. 2. What is analog computer?.................................................................................................................................................................................................................................................. 3. Write 1-2 lines on mainframe computers................................................................................................................................................................................................................................................... Self Assessment : Answer the following 1. Define the terms: data, program, hardware and software. 2. List and explain in brief the characteristics of computers. 3. Define a System. What constitutes a computer system? 4. Write short notes on Fourth Generation of Computers, Limitations of computers. 5. Explain the classification of computers on the basis of their capacity to access memory and size. 6. List the applications of computers.