Fundamentals of IT

• Digital computer


  Uses distinct values (0s and 1s) to represent data internally
• Analog computer


  Represents data as variable across a continuous range of values
• Characteristics of computer


  • Speed
  • Accuracy
  • Diligence
  • Storage capability
  • Versatility
• Speed


  Computer can process data very fast, at the rate of millions of instructions per second
• Accuracy


  Computer provides a high degree of accuracy
• Diligence


  Computer does not get tired or fatigued when used for a longer period of time
• Storage capability


  Large volumes of data and information can be stored in the computer and also retrieved whenever required
• Versatility


  Computer can perform different types of tasks with the same ease
• Computers have several limitations - they can only perform tasks they have been programmed to do, and cannot take their own decisions
• History of computing devices

  • Abacus
  • Napier's bones
  • Slide rule
  • Pascal's adding and subtraction machine
  • Leibniz's multiplication and dividing machine
  • Punch card system
  • Babbage's analytical engine
  • Hollerith's punched card tabulating machine
• Generations of computer


  • First generation (1940 to 1956): Using vacuum tubes
  • Second generation (1956 to 1963): Using transistors
  • Third generation (1964 to 1971): Using integrated circuits
  • Fourth generation (1971 to present): Using microprocessors
  • Fifth generation (present and next): Using artificial intelligence
• First generation computers


  • Used vacuum tubes for circuitry and magnetic drums for memory
  • Input through punched cards and paper tapes, output as printouts
  • Programmed in machine language
  • Computation time in milliseconds
  • Enormous in size and required large rooms
• Second generation computers


  • Used transistors instead of vacuum tubes
  • Used magnetic core technology for primary memory, magnetic tapes and disks for secondary storage
  • Input through punched cards, output as printouts
  • Programmed in assembly language and early high-level languages like COBOL and FORTRAN
  • Computation time in microseconds
  • Smaller in size compared to first generation
• Third generation computers


  • Used integrated circuit (IC) chips
  • Keyboard and monitor used for interaction instead of punched cards and printouts
  • Operating systems allowed running multiple applications
  • Extensively used high-level programming languages
  • Computation time in nanoseconds
  • Smaller in size compared to second generation
• Fourth generation computers


  • Use large scale integration (LSI) and very large scale integration (VLSI) technology
  • Microprocessor - a chip containing millions of transistors and components
  • Semiconductor memory replaced magnetic core memory
  • Smaller secondary storage devices with larger capacity
  • Computers linked to form networks and the internet
  • Graphical user interface (GUI) and pointing devices like mouse
  • Computation time in picoseconds
  • Smaller and more portable than previous generations
• The fifth generation of computers is focused on using artificial intelligence
• Picoseconds


  Unit of time, smaller than the computers of the previous generation
• Physical Appearance of 4th generation computers

  • Smaller than the computers of the previous generation
  • Some can even fit into the palm of the hand
• Application of 4th generation computers

  • Widely available for commercial purposes
  • Personal computers became available to the home user
• 4th generation computer components


  • Intel 4004 chip was the first microprocessor
  • Central Processing Unit (CPU) and memory were located on a single chip
  • IBM introduced the first computer for home use in 1981
  • Apple introduced the Macintosh in 1984
• 4th generation computers


  • Smaller and cheaper than their predecessors
  • Portable and more reliable
  • Generate much lesser heat and require less maintenance
  • GUI and pointing devices facilitate easy use and learning
  • Networking has resulted in resource sharing and communication among different computers
• 5th generation computers


  • Capable of learning and self-organization
  • Use Super Large Scale Integrated (SLSI) chips that are able to store millions of components on a single chip
  • Have large memory requirements
• 5th generation computers


  • Use parallel processing that allows several instructions to be executed in parallel, instead of serial execution
  • Faster processing speed
  • Based on Artificial Intelligence (AI) to simulate the human way of thinking and reasoning
• Classification of computers based on size and type

  • Microcomputers
  • Minicomputers
  • Mainframe computers
  • Supercomputers

  
• Microcomputers


  • Small, low-cost and single-user digital computer
  • Consist of CPU, input unit, output unit, storage unit and the software
  • Can be connected together to create a network of computers that can serve more than one user
• Minicomputers


  • Digital computers, generally used in multi-user systems
  • Have high processing speed and high storage capacity than the microcomputers
  • Can support 4–200 users simultaneously
• Mainframe computers


  • Multi-user, multi-programming and high performance computers
  • Operate at a very high speed, have very large storage capacity and can handle the workload of many users
  • Used in centralized databases
  • Users access via a terminal (dumb, intelligent or PC)
• Supercomputers


  • Fastest and the most expensive machines
  • Have high processing speed compared to other computers
  • Speed measured in FLOPS (FLoating point Operations Per Second)
  • Built by interconnecting thousands of processors that can work in parallel
• Computer system


  Consists of Hardware, Software, Data, and Users
• Hardware


  • Mechanical parts that make up the computer as a machine
  • Physical devices required for input, output, storage and processing of data
• Software


  • Set of instructions that tells the computer about the tasks to be performed and how these tasks are to be performed
  • Programs written in a language understood by the computer, to perform specific tasks
• Data


  • Isolated values or raw facts, which by themselves have no much significance
  • Processed by the computer to generate meaningful information
• Users


  • People who write computer programs or interact with the computer
  • Also known as skinware, liveware, humanware or peopleware
• Input-Process-Output concept


  1. Computer accepts input data

  2. Processes the input data

  3. Generates output

  4. Stores data
• Components of computer hardware

  • Input/Output (I/O) Unit
  • Central Processing Unit (CPU)
  • Memory Unit

  
• Input/Output Unit


  • User interacts with the computer via the I/O unit
  • Input unit accepts data and converts it into a form understandable by the computer
  • Output unit provides the processed data in a form understandable by the user
• Central Processing Unit (CPU)


  • Controls, coordinates and supervises the operations of the computer
  • Responsible for processing of the input data
  • Consists of Arithmetic Logic Unit (ALU) and Control Unit (CU)

  
• Memory Unit


  • Stores the data, instructions, intermediate results and output, temporarily, during the processing of data
  • Also called the main memory or primary memory
  • Secondary memory stores data, programs and output permanently
• Applications of computers


  • Education
  • Entertainment
  • Sports
  • Advertising
• Applications of computers


  • Download and view movies
  • Play games
  • Chat
  • Book tickets for cinema halls
  • Use multimedia for making movies
  • Incorporate visual and sound effects using computers
  • Listen to music
  • Download and share music
  • Create music using computers