Introduction to Computers PDF

# CHAPTER 1 ## INTRODUCTION TO COMPUTERS ### 1.1 History #### Introduction - A computer is a tool and partner in every sphere of human life and activity. - Computers are bringing many changes in industry, government, education, medicine, scientific research, law, service and even arts like music, m...

# CHAPTER 1 ## INTRODUCTION TO COMPUTERS ### 1.1 History #### Introduction - A computer is a tool and partner in every sphere of human life and activity. - Computers are bringing many changes in industry, government, education, medicine, scientific research, law, service and even arts like music, movies and paintings. - The areas of application of computers are confined only by the limitation of creativity and imagination. #### What is a computer? - An instrument capable of producing a combined effect of radio, movies and television. - It can process millions of instructions in a few seconds with high accuracy. - It can perform calculations or controlling operations that are expressible in numerical or logical terms. - It can perform assigned tasks very fast and doesn’t get bored. #### Early History - Humans have always needed to perform arithmetic like counting, either on their fingers or with the help of stone, pebble and beads. - The early civilization had men develop number systems to keep track of the astronomical cycles, businesses etc. - The word computing means ‘an act of calculating’. - After the invention of the manual calculating tools, the concept of using electronic gadgets’ for computations were introduced which gave birth to the computers. - The evolution of computers has passed through a number of stages before reaching the present state of development. - During this period, certain machines had been developed and a brief note of them is given below. - A computer is an electronic machine capable of performing basic operations like addition, subtraction, multiplication, division, etc. - The computer is also capable of storing information, which can be used later. #### Computer Generations - **First Generation (1940-1956): Vacuum Tubes** - The first generation of computers used vacuum tubes for circuitry and magnetic drums for memory. - They were large in size and occupied a lot of space. - They produced enormous heat and were expensive to operate. - They used machine language and had input based on punched cards. - Outputs were displayed as printouts. - **Examples:** UNIVAC and ENIAC. - **Second Generation (1956-1963): Transistors** - The second generation of computers saw vacuum tubes being replaced by transistors. - The transistor was more energy-efficient, reliable, and generated less heat compared to the vacuum tube. - Allowed computers to be smaller and more efficient. - Computers started storing their instructions in their memory, which moved from a magnetic drum to magnetic core technology. - **Examples:** IBM 1401 and IBM 7090. - **Third Generation (1964-1971): Integrated Circuits** - The development of the integrated circuit left its mark on the third generation of computers. - Transistors were made smaller and placed on silicon chips, which dramatically increased the efficiency of computers. - Transistors were cheaper and allowed to be more powerful and reliable. - This generation also brought in the use of high-level programming languages like COBOL and FORTRAN. - **Examples:** IBM System/360 and IBM System/370 - **Fourth Generation (1971-Present): Microprocessors** - The microprocessor brought forth the fourth generation of computers. - Thousands of integrated circuits were built onto a single silicon chip. - Microprocessors led to the development of personal computers (PCs) and the personal computer revolution. - The development of the internet also occurred during this generation. - **Examples:** Apple II, IBM PC, and Macintosh - **Fifth Generation (Present and Beyond): Artificial Intelligence** - Fifth generation computing devices, based on artificial intelligence, are still in their developmental stage. - Fifth generation computers will come close to bridging the gap between computing and thinking. - **Examples:** AI-powered robots and machines ### 1.2 Data, Information and Program - A computer is a tool for solving problems. - Computers accept instructions and data, perform arithmetic and logical operations and provide outputs based on these calculations. ### 1.3 Evolution of Computers - The evolution of electronic computers over a period of time can be traced effectively by dividing this period into various generations. - Each generation is characterized by a major technological development that fundamentally changed the way computers operated. - These helped to develop smaller, cheaper, powerful, efficient and reliable devices. ### 1.4 Brief History of Early Calculating Tools #### 2500 BC: Abacus - The first calculating machine known for counting. - Made with beads, cords, and used for simple arithmetic calculations. - Cords correspond to positions of decimal digits. - Beads present digits. - Numbers are represented by beads close to the crossbar. - It was mainly used for addition and multiplication. #### 1614 AD: Napier’s Bones - The Napier’s Bones was invented by John Napier, a Scottish mathematician as an aid to multiplication. - A set of bones contains rods, each representing a digit from 1 through 9 and a constant digit. - Each column on a rod represents a multiplication table. #### 1633: The Slide Rule - The Slide Rule was invented by William Oughtred. - It is based on the principle that the distance from the starting point of the rule is directly proportional to the logarithm of the numbers printed on the scales. - The slide rule embodied by two sets of scales that are joined together, with a marginal space between them. - Enabled the slide rule to perform multiplication, division and addition and subtraction by method. #### 1642: The Rotating Wheel Calculator - The Rotating Wheel Calculator was developed by French philosopher, Blaise Pascal. - It utilized simple components such as gears and levers. - Pascal was inspired by his predecessor to today’s electronic calculator. He was only 19 years old when he devised this model. #### 1822: The Difference Engine - The Difference Engine was built by Charles Babbage, a British mathematician and engineer. - It mechanically calculated mathematical tables. - It was considered the father of today’s computers. #### 1890: Hollerith Tabulating Machine - A tabulating machine using punched cards was designed by Herman Hollerith. - This electronic machine was able to read the information on the punched cards and process it electronically.