Operating Systems Fundamentals

Operating Systems

• Definition: A software that manages computer hardware resources and provides common services to computer programs
• Functions:
  • Process Management: creates, runs, and manages processes
  • Memory Management: allocates and deallocates memory for programs
  • File Management: provides access to file systems
  • Input/Output Management: manages input/output operations
  • Security: provides access control and protects against unauthorized access
• Types:
  • Single-User, Single-Tasking (e.g. MS-DOS)
  • Single-User, Multi-Tasking (e.g. Windows, macOS)
  • Multi-User, Multi-Tasking (e.g. Linux, Unix)

Computer Architecture

• Definition: The design and organization of a computer's internal components
• Components:
  • CPU (Central Processing Unit): executes instructions
  • Memory (RAM): temporary storage for data and programs
  • Storage (HDD, SSD): permanent storage for data and programs
  • Input/Output Devices: interfaces for user interaction
• Types:
  • Von Neumann Architecture: uses a single bus for data and instructions
  • Harvard Architecture: uses separate buses for data and instructions
  • RISC (Reduced Instruction Set Computing): uses a simplified instruction set
  • CISC (Complex Instruction Set Computing): uses a complex instruction set

Input/Output Devices

• Definition: Hardware components that allow users to interact with a computer
• Types:
  • Input Devices:
    • Keyboard: inputs text and commands
    • Mouse: inputs cursor movements and clicks
    • Scanner: inputs images and documents
    • Microphone: inputs audio
  • Output Devices:
    • Monitor: displays video and graphics
    • Printer: outputs printed documents
    • Speaker: outputs audio
    • Plotter: outputs graphical plots
• Interfaces:
  • Serial: transmits data one bit at a time
  • Parallel: transmits data multiple bits at a time
  • USB (Universal Serial Bus): a standardized interface for peripherals
  • HDMI (High-Definition Multimedia Interface): a standardized interface for audio and video

Operating Systems

• Manages computer hardware resources and provides common services to computer programs
• Performs process management, creating, running, and managing processes
• Manages memory allocation and deallocation for programs
• Provides access to file systems through file management
• Manages input/output operations and provides security features
• Single-user, single-tasking OS examples: MS-DOS
• Single-user, multi-tasking OS examples: Windows, macOS
• Multi-user, multi-tasking OS examples: Linux, Unix

Computer Architecture

• Refers to the design and organization of a computer's internal components
• Consists of CPU, memory, storage, and input/output devices
• CPU executes instructions, memory provides temporary storage, and storage provides permanent storage
• Input/output devices enable user interaction
• Von Neumann architecture uses a single bus for data and instructions
• Harvard architecture uses separate buses for data and instructions
• RISC architecture uses a simplified instruction set
• CISC architecture uses a complex instruction set

Input/Output Devices

• Enable user interaction with a computer
• Input devices include keyboard, mouse, scanner, and microphone
• Output devices include monitor, printer, speaker, and plotter
• Serial interface transmits data one bit at a time
• Parallel interface transmits data multiple bits at a time
• USB is a standardized interface for peripherals
• HDMI is a standardized interface for audio and video