Computer Language and Architecture

Computer Language: Binary System
  • Binary System: Communication system used by computers, known as base-2 numeral system.
  • Bit: Smallest unit of data in a binary system; can be either 0 or 1.
  • Byte: A group of 8 bits. Each byte can store one character (e.g., letters, digits).
    • There are 256 possible values for a byte, calculated as 28=2562^8 = 256.
Character Encoding
  • Character Encoding: Process of assigning binary values to characters for human readability.
  • ASCII:
    • Represents English alphabet, digits, and punctuation marks.
    • Example: Character 'a' maps to binary 0110000101100001.
    • Character table: Dictionary of binary mapping for characters.
  • UTF-8: Modern version of ASCII that allows for multiple bytes per character.
  • RGB Color Model: Uses three colors (Red, Green, Blue) to represent colors on screens, combining various byte values.
Binary Representation
  • Punch Card System: Earlier method of data input; a punched hole represented a binary '1'.
  • Logic Gates:
    • Used in transistors to perform complex operations based on binary input.
    • Output decisions are made according to logical conditions (on/off signals).
Types of Logic Gates

  1. AND Gate:

    • Takes two inputs. Outputs 'on' only when both inputs are 'on'.
    • Truth Table:
      • Input A | Input B | Output
      • Off | Off | Off
      • Off | On | Off
      • On | Off | Off
      • On | On | On

  2. OR Gate:

    • Outputs 'on' when at least one input is 'on'.
    • Truth Table:
      • Input A | Input B | Output
      • Off | Off | Off
      • Off | On | On
      • On | Off | On
      • On | On | On

  3. XOR Gate:

    • Outputs 'on' when exactly one input is 'on', not both.
    • Truth Table:
      • Input A | Input B | Output
      • Off | Off | Off
      • Off | On | On
      • On | Off | On
      • On | On | Off
Decimal Representation
  • Decimal System: Uses base-10 representation.
  • Highest Decimal Value for 1 Byte: 255 (calculated as 28−12^8 - 1).
Computer Architecture
  • Layer Abstraction: Simplifying complex systems for usability.
    • Example: Steering wheel controls the car despite complexity beneath.
  • Main Layers:
    1. Hardware Layer: Physical components (phones, laptops).
    2. Software Layer: Applications for human interaction (web browsers, apps).
    3. User: Individuals interacting with computers.
    4. Operating System: Manages hardware and software coordination.
Glossary of Terms
  • Abstraction: Simplifying complex systems.
  • Algorithm: Steps to solve a problem.
  • ASCII: Old character encoding standard.
  • Binary System: Base-2 communication system.
  • Byte: Group of 8 bits.
  • Character Encoding: Assigning binary values to characters.
  • Computer: Device for processing data.
  • Cryptography: Coding messages for security.
  • Decimal System: Base-10 system (0-9).
  • Digital Divide: Gap in digital literacy skills.
  • Information Technology: Use of digital tech for data processing.
  • Logic Gates: Components that perform logical functions.
  • Open Source: Software that can be modified and shared.
  • PDA: Mobile computing device.
  • Punch Cards: Early input method using cards.
  • RGB Model: Basis for color representation on screens.
  • UTF-8: Widely used character encoding standard.