Ch-1-Introduction to Computers science .ppt.pptx
- 1. © Oxford University Press 2012. All rights reserved. Computer Fundamentals and Programming in C Reema Thareja, Assistant Professor, Institute of Information Technology and Management
- 2. © Oxford University Press 2012. All rights reserved. CHAPTER 1 INTRODUCTION TO COMPUTERS 1st gen-1940-56 2nd gen 1956-63 3rd -64-71 4th —72-89 5th -mordern day
- 3. © Oxford University Press 2012. All rights reserved. INTRODUCTION TO COMPUTER SOFTWARE ● A computer is a machine that takes instructions and performs computations based on those instructions. CHARACTERISTICS OF COMPUTERS ● Speed ● Accuracy ● Automatic ● Diligence ● Memory ● No I.Q. ● Economical ● Versatile
- 4. © Oxford University Press 2012. All rights reserved. GENERATION OF COMPUTERS The word generation means the state of improvement in the product development process. Similarly, computer generation refers to the different advancements of new computer technology. First Generation (1940-1956) Vacuum Tubes The first generation computers used very large number of vacuum tubes for circuitry and magnetic drums for memory. UNIVAC and ENIAC computers are prime examples of first-generation computing devices.
- 5. © Oxford University Press 2012. All rights reserved. Advantages: Fastest calculating device of their time Disadvantages: 1. Dissipate a lot of heat 2. Consume a lot of electricity 3. Very bulky in size 4. These computers were frequently down due to hardware failures. 5. These computers needed constant maintenance because of low mean time between failures 6. Limited commercial use because these computers were difficult to program 7. Very expensive
- 6. © Oxford University Press 2012. All rights reserved. Second Generation (1956-1963) Transistors ●The second generation computers were manufactured using transistors. ●While first generation computers were programmed using machine language, second generation computers moved towards symbolic, or assembly languages, which allowed programmers to specify instructions in words. ●At this time, high-level programming languages like COBOL, FORTRAN, ALGOL and SNOBOL were also being developed. ●Second generation computers were first to store instructions in memory, which moved from a magnetic drum to magnetic core technology. ●Second generation computers were first developed for the atomic energy industry.
- 7. © Oxford University Press 2012. All rights reserved. Advantages: 1. Consumed less electricity and thus dissipated less heat as compared to first generation computers 2. Faster, cheaper smaller and more reliable than first generation computers 3. Could be programmed using assembly language and high level languages 4. These computers had faster primary memory and a larger secondary memory Disadvantages: 1. Second generation computers were manufactured using transistors that had to be assembled manually. This made commercial production of computers difficult and expensive.
- 8. © Oxford University Press 2012. All rights reserved. Third Generation (1964-1971) Integrated Circuits ● The development of the integrated circuit was the hallmark of the third generation of computers. ● These computers had few megabytes of main memory and magnetic disks which could store few tens of megabytes of data per disk drive. ● High level programming languages like COBOL and FORTRAN were standardized by ANSI ● Some more high level programming languages like PL/I PASCAL and BASIC were introduced at this time. ● Third generation computers were the first to implement time sharing operating systems. ● Input to these computers could now be provided using keyboards and mouse.
- 9. © Oxford University Press 2012. All rights reserved. Advantages: ●Faster than second generation computers and could perform 1 million transactions per second. 2. Smaller, cheaper and more reliable than their predecessors 3. These computers had faster and larger primary memory and secondary storage 4. They were widely used for scientific as well as business applications 5. During this generation of computers, standardization of existing high level languages and invention of new high level languages was done 6. These computers had time sharing operating system which allowed interactive use of computer by one or more users simultaneously thereby improving the productivity of the users.
- 10. © Oxford University Press 2012. All rights reserved. Fourth Generation (1971-1989) Microprocessors The microprocessor started the fourth generation of computers with thousands of integrated circuits built onto a single silicon chip. Fourth Generation (1971-1989) Microprocessors The microprocessor started the fourth generation of computers with thousands of integrated circuits built onto a single silicon chip. Fourth Generation (1971-1989) Microprocessors The microprocessor started the fourth generation of computers with thousands of integrated circuits built onto a single silicon chip. Fourth Generation (1971-1989) Microprocessors ●The microprocessor started the fourth generation of computers with thousands of integrated circuits built onto a single silicon chip. ●Semi-conductor memories were used which were very fast, even the hard disks became cheaper, smaller in size and larger in capacity. ●For input, floppy disks (in addition to magnetic tapes) were used to port data and programs from one computer to another. ●During this period many new operating systems were developed like MS-DOS MS-Windows UNIX and Apple’s proprietary operating system. ●Development of GUIs, the mouse and handheld devices. ●In this period, several word processing packages, spreadsheet packages and graphics packages were introduced.
- 11. © Oxford University Press 2012. All rights reserved. Advantages: 1. Smaller, cheaper, faster and more reliable 2. Consumed less electricity and therefore dissipated less heat 3. They had faster and larger primary memory and secondary storage 4. They could be used as general purpose computers. 5. GUIs enabled people to learn to work with computers very easily. So the use of computers in both office and home became widespread. 6. Networks allowed sharing of resources thereby efficient utilization of computer hardware and software
- 12. © Oxford University Press 2012. All rights reserved. Fifth Generation (Present and Beyond) Artificial Intelligence ●The fifth generation computers are completely based on a new concept of artificial intelligence. ● Although such computers are still in development, there are certain applications like voice recognition which is widely being used today. ●In the fifth generation of computers the aim is to develop devices that respond to natural language input and are capable of learning and self- organization. ● The two most common are LISP and Prolog.
- 13. © Oxford University Press 2012. All rights reserved. CLASSIFICATION OF COMPUTERS Computers can be broadly classified into four categories based on their speed, amount of data that they can hold and price. CLASSIFICATION OF COMPUTERS Computers can be broadly classified into four categories based on their speed, amount of data that they can hold and price. CLASSIFICATION OF COMPUTERS Computers can be broadly classified into four categories based on their speed, amount of data that they can hold, and price. Classification of Computers Super Computer Mini Computers Mainframe Computers Micro Computers Intelligent Terminal Dumb Terminal Laptop Workstation Network Desktop Handheld Cellular Telephones H/PC Pro Devices Network
- 14. © Oxford University Press 2012. All rights reserved. APPLICATIONS OF COMPUTERS ● Word Processing ● Internet ● Digital Audio or Video Composition ● Desktop Publishing ● Government ● Traffic Control ● Legal System ● Retail Business ● Sports ● Travel and Tourism ● Hospitals ● Business and Industry ● Geology ● Astronomy ● Weather Forecasting ● Simulation ● Education ● Online Banking ● Industry and Engineering ● Robots ● Decision Support Systems ● Expert Systems
- 15. © Oxford University Press 2012. All rights reserved. BASIC ORGANIZATION OF A COMPUTER A computer is an electronic device which basically performs five major operations which includes: 1) accepts data or instructions (input) 2) stores data 3) process data 4) displays results (output) and 5) controls and co-ordinates all operations inside a computer INPUT STORAGE OUTPUT CPU CONTROL UNIT ARITHMETIC LOGIC UNIT Data and instructions Results Flow of data and instructions Control exercised by control unit