Lecture Notes on Computers

Introduction

• Overview of what will be covered in the unit:
  • Definition and uses of computers
  • Capabilities and limitations of computers
  • Classification and types of computers
  • History and evolution of computers
  • Basic operations and organization of computers

Learning Objectives

By the end of this unit, you should be able to explain:

• What is a computer?
• Basic units of computers and their purpose
• How computers work
• Features of computers
• Uses and applications of computers
• Types and generations of computers
• Basic computer operations

Characteristics of Computers

Key Features

• High Speed
  • Measured in megahertz (MHz) for personal computers (300 MHz to 2 GHz)
  • Workstations and mainframes measured in millions of instructions per second (MIPS) (20 to 1000 MIPS)
  • Supercomputers measured in giga flops (1 billion) and tera flops (1 trillion).
• Reliability and Accuracy
  • Highly reliable results and precise calculations
  • Error-checking systems built in to minimize errors
  • Backup systems for data recovery
• Large Memory
  • Temporary memory (RAM) for currently executing programs
  • Permanent memory (hard disks) for data storage
  • Able to dynamically access data regardless of storage location
• Logical Decision Making
  • Ability to perform logical operations and comparisons
  • Used in artificial intelligence applications
• Versatility
  • Able to solve a variety of problems in different fields (communications, multimedia, research, etc.)
• Automation
  • Executes instructions automatically upon startup
• Diligence
  • Can perform repetitive tasks without fatigue, maintaining precision

Limitations of Computers

• Lack of Intelligence
  • Cannot think or have aesthetic senses like humans
• Environmental Requirements
  • Need dust-free environments and specific temperature conditions
• Language Requirements
  • Understanding only binary code, requiring special interpreters

Historical Overview of Computers

• Early Tools
  • Abacus (5000 years ago): manual counting device
• Blaise Pascal (1640)
  • Invented Pascaline for calculations
• Joseph Marie Jacquard (1801)
  • Created Jacquard loom using punched cards
• Charles Babbage (1842)
  • Developed the first general-purpose mechanical computer (Difference Engine, Analytical Engine)
  • Lady Ada Lovelace: first programmer
• Herman Hollerith (1890)
  • Developed electromechanical punch card tabulating machine, leading to modern data processing
• John Atanasoff & Clifford Berry (1939-1942)
  • Developed the first modern digital computer (Atanasoff-Berry Computer)
• ENIAC (1946)
  • First large-scale digital computer used for military applications
• Colossus (1943)
  • Designed to break German codes during WWII
• Edsac & Edvac (1949-1950)
  • Early stored-program computers
• Second Generation (1959)
  • Transition from vacuum tubes to transistors
• Third Generation (1964)
  • Introduction of integrated circuits
• Fourth Generation (1971)
  • Microprocessors introduced, leading to personal computers
• Rise of Personal Computing
  • Apple II (1975), IBM PC (1981), emergence of Microsoft and GUI

Conclusion

• Continuous advancements in microprocessor technology and computing capabilities
• Expect significant changes in computing technology.