Introduction to Computers

Computer Fundamentals

• Date of session: 07.01.2025
• Session number: I
• Topic: Introduction to computers
• Faculty: Dr. Amar Nath, Department of CSE, SLIET Longowal

Contents Covered

• Overview
• Introduction to Computers
• Characteristics of Computers
• History/Evolution of Computers
• Generations of Computers

Overview of Unit I

• Introduction to Computers
• Classification of Computers
• Characteristic Applications of Computers
• Block Diagram

Overview of Unit II

• Computer Organization
• Memory Units
• Input Devices
• Output Devices

Introduction to Computers: Definition

• It's an electronic device for information processing.
• 'Computer' originates from the Latin word 'compute'.
• The primary function of a computer is that of calculation.
• A computer system consists of a computer, peripheral devices and software.

Basic Computer Operations

• Accepting data/instructions via input
• Storing Data
• Processing Data as required by the user
• Returning results in form of an output
• Controlling all operations inside the computer
• A computer accepts input, processes data, stores data, and produces output

Key Terms

• Input: Refers to whatever is sent to a Computer system
• Data: Refers to the symbols that represent facts, objects, and ideas
• Processing: The way that a computer manipulates data
• CPU: Central Processing Unit, device which computer processes data
• Memory: Area of a computer that holds data that is waiting to be processed, stored, or output
• Storage: Area where data can be left on a permanent basis
• Computer Output: Result produced by the Computer

Other Key information

• Computer performs computations and makes logical decisions
• Computers perform instructions millions / billions times faster than human beings
• Computer programs are the sets of instructions for which computer processes data
• Hardware are the physical devices of computer system
• Software are the programs that run on computers

Basic Components of a Computer

• Input/Output Unit: Keyboard and Printer
• Storage Unit:
• Main: Read-Only Memory (ROM) and Random Access Memory (RAM)
• Secondary: HDD, CD
• Central Processing Unit (CPU):
• Control Unit: Acts as the supervisor and determines sequence of program/instruction execution
• Arithmetic Logic Unit (ALU): Where the actual execution of instructions, calculations, and comparisons take place

Capabilities of Computers

• Huge Data Storage
• Input & Output
• Processing

Characteristics of Computers

• High Processing Speed (in seconds, ms, ns)
• 100% Accuracy
• Reliability: Ability to work without failure
• Versatility: Ability to perform a wide range of jobs
• Diligence: Freedom from monotony, tiredness, and lack of concentration

History of Computers

• Before the 1500s, Europe, calculations were made with an abacus around 500BC.
• The abacus was used in China, Mesopotamia, Japan, Greece, Rome
• In 1642, Blaise Pascal invented the Pascaline, a mechanical calculator.
• In 1671, Gottfried von Leibniz created the Stepped Reckoner, extending the Pascaline to do multiplications, divisions, square roots.
• None of these machines had memory and they required human intervention at each step
• In 1822, Charles Babbage designed the Difference Engine, an automatic computation machine for polynomial functions, which was based on the "method of finite difference" and implements some storage.
• In 1833, Charles Babbage designed the Analytical Engine, which was completed after his death and powered by Steam.

Generations of Computers

• First Generation: 1946-59, based on vacuum tube technology
• Second Generation: 1957-64, based on transistor technology, replacing vacuum tubes
• Third Generation: 1965-70, integrated circuit (IC) technology developed
• Fourth Generation: 1970-90, microprocessors developed
• Fifth Generation: 1990-present, use of Bio-Chip technology

Computer Generations: Technology & Size

• First Generation:
  • Vacuum Tubes
  • Filled Entire Buildings
• Second Generation:
  • Transistors.
  • Filled Half a Room
• Third Generation:
  • Integrated Circuits (multiple transistors)
  • Smaller
• Fourth Generation:
  • Microchips (millions of transistors)
  • Size of a Palm Pilot but as powerful as an old building-sized computer

First Generation Computer

• ENIAC (Electronic Numerical Integrator and Calculator), was the first all-electronic computer.
• It was built at the Moore School of Engineering, University of Pennsylvania by J. Presper Eckert and John Mauchly.

Third Generation Computer

• Seymour Cray created the Cray Research Corporation.
• The Cray-1 cost $8.8 million, performed 160 million instructions per second, and had 8 Mbytes of memory

Fourth Generation Computer

• Improvements in IC technology integrated more transistors on a single chip.
• SSI (Small Scale Integration): 10-100 transistors
• MSI (Medium Scale Integration): 100-1,000 transistors
• LSI (Large Scale Integration): 1,000-10,000 transistors
• VLSI (Very Large Scale Integration): more than 10,000 transistors

Types of Computers

• Super Computer
• Mainframe Computer
• Mini Computer
• Micro Computer

Fifth Generation Computer

• Term refers to "sci-fi" future developments.
• Voice recognition
• Artificial intelligence
• Quantum computing
• Bio Computing
• Nano technology
• Learning
• Natural languages

Supercomputers

• Fastest and most expensive computers.
• Used for specialized applications with heavy mathematical calculations. Weather forecasting requires a supercomputer.
• Other applications: animated graphics, fluid dynamic calculations, nuclear energy research, and petroleum exploration

Mainframe Computers

• Very large and expensive, supports hundreds/thousands of users simultaneously.
• Just below supercomputers in hierarchy, above microprocessors.
• Mainframes support simultaneous programs, while supercomputers are faster at executing a single program.

Mini Computers

• Mid-sized computers that lie between workstations and mainframes.
• The distinction between large minicomputers and small mainframes has blurred in recent years.
• A minicomputer is a multiprocessing system supporting 4-200 simultaneous users.

Micro Computers

• Desktop Computer: A personal or micro-mini computer that fits on a desk
• Laptop Computer: A portable computer with an integrated screen and keyboard
• Palmtop Computer/Digital Diary/Notebook/PDA: A hand-sized computer that lacks a physical keyboard, using the screen for both input and output

Workstations

• A terminal or desktop computer in a network.
• Generic term for a user's (client) machine, as opposed to a "server" or "mainframe."

Learn the basics of computers, their characteristics, history, and generations. Explore computer organization, memory units, input/output devices, and fundamental operations. Understand how computers process data and deliver results.