Csc200

• Now that computer is ubiquitous, being present in every aspect of our daily life, its basic meaning has not changed, except for the fact that different applications may ascribe different meanings to it.
• Computer


  (modern definition) a programmable electronic device that can store, retrieve, and process data
• Algorithm


  A sequence of instructions needed to perform a task
• Computer operation


  1. Accepts data and instructions

  2. Executes instructions on data

  3. Produces results or performs actions as output
• Simple computer model


  • Input unit
  • Processor
  • Output unit
• Input unit


  Provides a mechanism for a computer to accept data and instructions from users
• Memory unit


  Stores data and instructions obtained from the input unit as well as processed results for future use
• Volatile memory


  Computer memory that is capable of retaining information for a very short duration
• Non-volatile memory


  Secondary or auxiliary storage that can store large data for a long time
• Processing unit (CPU)


  Accepts data and instructions from the primary memory, executes instructions and produces results
• Arithmetic and Logic Unit (ALU)


  Unit that executes instructions involving arithmetic and logical calculations
• Control Unit (CU)


  Unit that executes instructions involving the control operations of computer components
• Output unit


  Mechanism for displaying results of the processed data from the processing unit
• Characteristics of a computer

  • Automation
  • Speed
  • Accuracy
  • Storage
  • Versatility
  • Communications
  • Multitasking
  • Diligence
• Advantages of computers include:

  1. Enables processing of large volumes of data at high speed

  2. Reduces cost of data operations

  3. Ensures consistent and error-free processing

  4. Enables development of high-quality applications and real-time applications
• Disadvantages of computers include:

  1. Highly dependent on quality of input data

  2. Programming a computer is costly and time-consuming

  3. Computer systems are rigid and costly to modify

  4. Require sophisticated equipment and support facilities
• Software


  Intangible part of a computer, consisting of programs and operating information to direct the operation of a computer
• Types of software


  • Systems software
  • Applications software
• Hardware


  Tangible or physical part of a computer, including the processor, motherboard, input/output devices
• Firmware


  Software integrated into the hardware, providing low-level control for devices
• Types of computers by operation principle

  • Analog
  • Digital
  • Hybrid
• Analog computer


  Operates on continuous range of values, deals with physical variables like voltage, pressure, temperature
• Digital computer


  Operates on digital data using binary number system, can give more accurate and faster results
• Types of digital computers

  • General purpose
  • Special purpose
• Hybrid computer


  Combines desirable features of analog and digital computers, used for automatic operations of complicated physical processes and machines
• Classification of digital computers by size and performance


  • Supercomputers
  • Mainframe computers
  • Minicomputers
  • Microcomputers

  
• Hybrid Computers


  Computers that combine the desirable features of analog and digital computers
• Hybrid Computers


  • Mostly used for automatic operations of complicated physical processes and machines
  • Use analog-to-digital and digital-to-analog converters to transform data into suitable form for either type of computation
• Hybrid Computers


  • In hospital's ICU, analog devices measure patient temperature, blood pressure and other vital signs. These analog measurements are then converted into numbers and supplied to digital components in the system to monitor the patient's vital signs and send signals if any abnormal readings are detected
• Hybrid Computers

  Mainly used for specialized tasks
• Classification of digital computers based on size and performance


  • Supercomputers
  • Mainframe Computers
  • Minicomputers
  • Microcomputers

  
• Supercomputers


  • High processing capacity
  • Generally the most expensive
  • Can process billions of instructions per second
  • Used for applications requiring intensive numerical computations such as stock analysis, weather forecasting, scientific simulations, (animated) graphics, fluid dynamic calculations, nuclear energy research, electronic design, and analysis of geological data
• Mainframe Computers

  • Used primarily by large organizations for critical applications, bulk data processing such as census, industry and consumer statistics, enterprise resource planning and transaction processing
  • Can process data at very high speeds, i.e., hundreds of million instructions per second
  • Quite expensive
  • Used in banking, airlines, railways and many other scientific applications
• Minicomputers


  • Lower to mainframe computers in terms of speed and storage capacity
  • Less expensive than mainframe computers
  • Some features of mainframes will not be available
  • Performance less than that of mainframes
• Microcomputers


  • Computers made possible by the invention of the microprocessor (single chip CPU)
  • Further classified into desktop, laptop and handheld computers
• Desktop Computers


  • The most popular computer systems
  • Also known as personal computers or PCs
  • Easier to use and more affordable
  • Intended for individual users for their word processing and other small application requirements
• Laptop Computers


  • Portable computers
  • Lightweight with a thin screen
  • Also called notebook computers because of their small size
  • Can operate on batteries, making them popular with travelers
  • Screen folds down onto the keyboard when not in use
• Handheld Computers (PDAs)


  • Pen-based and battery-powered
  • Small and can be carried anywhere
  • Use a pen-like stylus and accept handwritten input directly on the screen
  • Not as powerful as desktops or laptops
  • Used for scheduling appointments, storing addresses and playing games
  • Have touch screens which can be used with a finger or a stylus
• When analysing markets, a range of assumptions are made about the rationality of economic agents involved in the transactions
• The Wealth of Nations was written

  1776