Chapter 1: Introduction of Computer

Computer Science – Class 11

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Chapter 1: Introduction of Computer

1.1 Introduction of Computer

1.1.1 Definition, Characteristics, and Applications of Computers

Definition:
A computer is an electronic device that processes data, performing calculations and executing instructions to produce meaningful information. It can store, retrieve, and manipulate data efficiently.

Characteristics:

  1. Speed: Computers can perform millions of calculations per second.
  2. Accuracy: They provide accurate results, minimizing human errors.
  3. Automation: Once programmed, computers can perform tasks automatically without human intervention.
  4. Storage Capacity: Computers can store vast amounts of data.
  5. Versatility: They can perform various tasks, from simple calculations to complex simulations.
  6. Diligence: Computers can work continuously without fatigue or loss of concentration.
  7. Connectivity: They can connect to networks and the internet, facilitating data sharing and communication.

Applications:

  • Business: Managing finances, inventory, and customer relations.
  • Education: E-learning platforms, research, and digital classrooms.
  • Healthcare: Patient record management, diagnostics, and telemedicine.
  • Entertainment: Gaming, multimedia, and streaming services.
  • Science and Engineering: Data analysis, simulations, and modeling.

1.1.2 Evolution of Computer Technology

The evolution of computer technology can be traced through several generations, each marked by significant advancements:

  1. First Generation (1940-1956): Used vacuum tubes for circuitry and magnetic drums for memory. Examples: ENIAC, UNIVAC.
  2. Second Generation (1956-1963): Transistors replaced vacuum tubes, making computers smaller and more efficient. Examples: IBM 7094, CDC 1604.
  3. Third Generation (1964-1971): Integrated circuits (ICs) emerged, allowing more components to fit on a single chip. Examples: IBM System/360.
  4. Fourth Generation (1971-Present): Microprocessors were developed, leading to the personal computer (PC) revolution. Examples: Intel 4004, Apple Macintosh.
  5. Fifth Generation (Present and Beyond): Focuses on artificial intelligence, machine learning, and quantum computing. Current technologies include neural networks and advanced algorithms.

1.1.3 Measurement Unit of Processing Speed and Storage Unit

Processing Speed:

  • Measured in Hertz (Hz), representing the number of cycles per second.
    • Kilohertz (kHz): 1,000 Hz
    • Megahertz (MHz): 1,000,000 Hz
    • Gigahertz (GHz): 1,000,000,000 Hz

Storage Unit:

  • Bit: Smallest unit of data (0 or 1).
  • Byte: 8 bits.
  • Larger units include:
    • Kilobyte (KB): 1,024 Bytes
    • Megabyte (MB): 1,024 KB
    • Gigabyte (GB): 1,024 MB
    • Terabyte (TB): 1,024 GB

1.1.4 Supercomputers, Mainframe, Mini, and Microcomputers

  1. Supercomputers:

    • High-performance systems used for complex computations (e.g., weather forecasting, scientific simulations).
    • Example: Summit, Fugaku.

  2. Mainframe Computers:

    • Large and powerful systems capable of processing and storing vast amounts of data.
    • Typically used in large organizations for bulk data processing (e.g., banking).
    • Example: IBM zSeries.

  3. Minicomputers:

    • Mid-range computers, smaller than mainframes but larger than microcomputers.
    • Used for small to medium-sized businesses.
    • Example: PDP-11.

  4. Microcomputers:

    • Personal computers designed for individual use.
    • Include desktops, laptops, tablets, and smartphones.
    • Example: Dell Inspiron, Apple MacBook.

1.1.5 Mobile Computing and its Applications

Mobile Computing:

  • Refers to the ability to use computing devices while on the move, utilizing wireless networks.
  • Involves portable devices like smartphones, tablets, and laptops.

Applications:

  • Communication: Instant messaging, video calls, and emails.
  • Navigation: GPS services for real-time location tracking.
  • Mobile Banking: Financial transactions via banking apps.
  • Social Media: Accessing platforms like Facebook, Instagram, and Twitter.
  • E-commerce: Online shopping through mobile applications.

1.2 Computer System and I/O Devices

1.2.1 Concept of Computer Architecture and Organization

  • Computer Architecture: Refers to the design and structure of a computer system, including its hardware components and their interactions.
  • Computer Organization: Describes the operational units and their interconnections in the architecture.

1.2.2 Components of Computer System

  1. Input Unit: Accepts data and instructions from the outside world (e.g., keyboard, mouse).
  2. Output Unit: Sends processed data to the outside world (e.g., monitor, printer).
  3. Processing Unit: Performs calculations and logical operations (e.g., CPU).
  4. Memory Unit: Temporarily holds data and instructions (e.g., RAM).
  5. Storage Unit: Stores data permanently or semi-permanently (e.g., hard drives, SSDs).

1.2.3 Microprocessor: Basic Concepts, Clock Speed, Word Length, Components, and Functions

  • Microprocessor: The brain of a computer that performs computations and processes instructions.
  • Clock Speed: Measured in GHz, it indicates how many cycles per second the processor can execute.
  • Word Length: The number of bits the processor can process in a single operation (e.g., 32-bit, 64-bit).
  • Components: Includes ALU (Arithmetic Logic Unit), Control Unit, and registers.
  • Functions: Executes instructions, performs calculations, and controls data flow within the computer.

1.2.4 Bus System: Data Bus, Address Bus, and Control Bus

  • Bus System: A communication system that transfers data between components.
    • Data Bus: Transfers actual data between components (e.g., CPU, memory).
    • Address Bus: Carries memory addresses from the CPU to other components, specifying where data should be sent or retrieved.
    • Control Bus: Transmits control signals from the CPU to manage the operations of other components.

1.2.5 Primary Memory

  • Definition: Temporary storage that provides fast access to data.
  • Types:
    • RAM (Random Access Memory): Volatile memory used for temporary data storage.
    • ROM (Read-Only Memory): Non-volatile memory used for permanent storage of firmware.
    • Cache: A smaller, faster type of volatile memory that stores frequently accessed data.
    • Buffer: Temporary storage used to hold data while it is being transferred between two devices.

1.2.6 Secondary Memory

  • Definition: Non-volatile storage used for permanent data storage.
  • Types:
    • Magnetic Disk: Hard drives and floppy disks that use magnetic storage.
    • Flash Memory: USB drives and SSDs that use flash memory technology.
    • Optical Disk: CDs, DVDs, and Blu-rays that use laser technology for reading and writing data.
    • External Storage Devices: Devices like external hard drives and memory cards.
    • Memo Stick: A form of removable flash memory.

1.2.7 Input Devices

  • Devices that allow users to enter data into a computer system.
    • Keyboard: Standard input device for text and commands.
    • Mouse: Pointing device for graphical interfaces.
    • Scanner: Converts physical documents into digital format.
    • Light Pen: A pointing device used for selecting objects on a screen.
    • OMR (Optical Mark Recognition): Reads marked answers on documents (e.g., answer sheets).
    • OCR (Optical Character Recognition): Converts printed text into digital text.
    • BCR (Barcode Reader): Scans barcodes for data input.
    • MICR (Magnetic Ink Character Recognition): Reads special characters printed with magnetic ink.
    • Touch Screen: Allows direct interaction with the display.
    • Microphone: Captures audio input.
    • Digital Camera: Captures images and videos for input.

1.2.8 Output Devices

  • Devices that convey information from a computer to the user.
    • Monitor: Displays visual output; types include LCD and LED.
    • Printer: Produces hard copies; types include Dot Matrix, Inkjet, and Laser.
    • Speaker: Outputs audio signals.

1.2.9 Hardware Interfaces

  • Connections that allow different hardware components to communicate with each other.
    • Parallel Port: Used to connect printers and other peripherals.
    • Serial Port: Transfers data one bit at a time, often used for older devices.
    • USB Ports: Universal interface for connecting various devices like flash drives and keyboards.
    • HDMI: High-Definition Multimedia Interface for transmitting audio and video.
    • Expansion Slots: Allow additional hardware components (e.g., graphics cards, sound cards) to be added to the motherboard.
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