Lecture 3


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Lecture 3

  1. 1. Classification of Computers
  2. 2. Classification of Computers There are 4 categories of computers- 2. Super Computer 3. Mainframe 4. Mini Computer 5. Micro Computer
  3. 3. Classification of Computers Super Computer • The highly sophisticated computer. • The most powerful computer made till now. • Used for very special, highly calculation- intensive tasks like scientific research, weather forecasting, quantum mechanical physics, climate research (global warming), molecular modeling, physical simulations (nuclear weapons), pollution control. Major universities, military agencies and scientific research laboratories are heavy users.
  4. 4. Classification of Computers …Super Computer • Very expensive, priced from $ 2 million to $ 20 million. • Consume huge electricity, enough to lighten about 100 houses. • Can have hundreds of processors. • Speed is measured in nanoseconds.
  5. 5. Classification of Computers Mainframe A mainframe has •1 to 16 CPUs (modern machines more) •Memory ranges from 128 Mb over 8 Gigabyte on line RAM •Its processing power ranges from 80 over 550 Mips It has often different cabinets for •Storage •I/O •RAM
  6. 6. Classification of Computers …Mainframe Separate processes (program) for •Task management •Program management •Job management •Serialisation •Catalogs •Inter address space •Communication
  7. 7. Classification of Computers … Mainframe • Used by large organisations for critical applications, where many people need frequent access to the same information. • large and expensive • have the ability to run multiple operating systems and thereby operate not as a single computer but as a number of virtual machines. A single mainframe can replace dozens or even hundreds of smaller servers, reducing management and administrative costs while providing greatly improved reliability.
  8. 8. Classification of Computers …Mainframe • Front End processor handles communication to & from all the remote terminals connected to the computer system. •Back End processor handles retrieval operations. • Cost is above $35000. •Occupy entire rooms or sometimes entire floor of a building. • Can support upto several hundred users simultaneously. • Supports multiprogramming.
  9. 9. Classification of Computers Mini Computer • A midsized computer. In size and power, it is less than mainframes. • Is a multiprocessing system capable of supporting from 4 to 200 users simultaneously. • Can handle a great amount of data • Can support a number of terminals. • Slower than mainframes but support as many terminals as a mainframe can.
  10. 10. Classification of Computers …Mini Computer • Lesser storage capacity. • Used for R&D Organisations and Universities. • Range is from $18,000 to $50,000.
  11. 11. Classification of Computers Micro Computer • Small in size. • Single user computer. • Much slower than the larger computers. • Used in small businesses, homes, and school/ colleges classrooms. • Inexpensive and easy to use. • Also called PCs in short for Personal computers.
  12. 12. Classification of Computers …Micro Computer • Support multitasking. Types of Microcomputers are – • Desktop – small enough to fit on a desk but are too big to carry around. • Laptop/Notebook – portable, light weight computers, can be carried around. can store the same amount of data and having a memory of the same size as that of a personal computer.
  13. 13. Classification of Computers …Micro Computer c) PDA – Personal Digital Assistant is the smallest portable computer, not bigger than a cheque book, also known as palmtops. These are used for keeping record of phone numbers, dates etc. These also come with touch screen or electronic pen.
  14. 14. Generations of Computers
  15. 15. 1st Generation of Computers 1940-1956: Vacuum Tubes – Technology used was vacuum tubes – Very large in size, taking up entire rooms. – Generated lot of heat – Consumed a lot of electricity – Low capacity internal storage – Individual non related models – Speed of processors was in milliseconds – Used magnetic drum and delay lines for Internal storage. UNIVAC & ENIAC – Used machine language to perform operations.
  16. 16. 2nd Generation of Computers 1956-1963: Transistors – Vacuum tubes were replaced with transistors – Smaller in size than the previous Generation – Generated low level of heat as components were much smaller – Greater reliability – Higher capacity internal storage – Individual non related models – Faster, speed of processors was in microseconds – Use of high cost magnetic IBM-140, HONEY-WELL core storage instead of magnetic drum.
  17. 17. …2nd Generation of Computers 1956-1963: Transistors – Used Assembly Language to perform operations. – High Level Programming Languages like early versions of COBOL & FORTRAN were also being developed. IBM-1400, HONEYWELL400
  18. 18. 3rd Generation of Computers 1964-1971: Integrated Circuits – Transistors were replaced with IC – Smaller in size than the previous generation – Remote communication facility – Multi programming facility – Reduced cost of direct storage – Higher capacity of internal storage – Speed of processors was in nanoseconds – Use of high level languages like COBOL – Use of wide range of optical peripherals
  19. 19. 4th Generation of Computers 1971-Present: Microprocessor – ICs were improvised to LSI and then VLSI – The Microprocessor brought the fourth generation of computers, as thousands of integrated circuits were built onto a single silicon chip. – Smaller in size, could now fit in the palm of the hand – Network Communication facility enhanced – Multi programming/ Multi processing facilities – Reduced cost of direct access storage – Higher capacity of internal storage – Speed of processors in picoseconds.
  20. 20. …4th Generation of Computers 1971-Present: Microprocessor – Use of 4th generation languages. – Much greater data processing capacity. – Development of GUIs, the mouse, and handheld devices. – Web based software development for business and other applications.
  21. 21. 5th Generation of Computers Present and Beyond: Artificial Intelligence – Based on Artificial Intelligence. – Easy to use computers with high intelligence & natural human I/P, O/P mechanisms. – Reliable & efficient software development by new languages, new computer architectures & system software which overcomes previous shortcomings. – Improved overall functions & performance aimed at making computers smaller, lighter, faster, of greater capacity, more flexible & more reliable. – Are still in development, though there are some applications, such as voice recognition, that are being used today.
  22. 22. …5th Generation of Computers – The use of parallel processing and superconductors is helping to make artificial intelligence a reality. – The goal of fifth-generation computing is to develop devices that respond to natural language input and are capable of learning and self-organisation. – Focus on Internet and Intranets. – Non-procedural programming environment.
  23. 23. Assignment • What is LSI, VLSI? • Describe First generation, second generation, third generation computers. • Differentiate super computer and mainframe. • Identify characteristics of fifth generation computers. • What is the similarity between mainframes and minicomputers?