Types of Operating System Functions

• What is the purpose of an operating system?

  To manage hardware and provide user interface
• What does the boot loader do?

  Loads the OS into RAM at startup
• What are the main functions of an operating system?

  User interface, memory management, interrupt handling
• What are the components of memory management in an operating system?

  • Allocation of RAM to programs
  • Paging
  • Segmentation
  • Virtual memory
• What is paging in memory management?

  Dividing memory into fixed-size chunks called pages
• How does a page table function?

  Maps logical memory locations to physical locations
• What is segmentation in memory management?

  Dividing memory into segments of different lengths
• What is virtual memory?

  Hard disk space used as additional RAM
• What is disk thrashing?

  Excessive swapping of pages between RAM and disk
• What are interrupts in a CPU?

  Signals that temporarily halt CPU processing
• What can send interrupts to the CPU?

  Software, hardware devices, internal clock
• What happens when an interrupt is detected?

  The CPU stops fetching instructions and processes the interrupt
• What is an Interrupt Service Routine (ISR)?

  Code that processes the interrupt
• How does the CPU handle interrupt priorities?

  Processes interrupts in order of priority
• What is the purpose of processor scheduling?

  To manage CPU time for multiple applications
• What are the aims of processor scheduling?

  • Provide acceptable response time
  • Maximize CPU engagement
  • Ensure fairness in multi-user systems
• What is the Round Robin scheduling algorithm?

  Allocates time slices to each job in FIFO order
• How does First Come First Served scheduling work?

  Executes the first job until completion
• What is the Shortest Remaining Time scheduling algorithm?


  Executes the job with the shortest remaining time
• What does 'starvation' mean in scheduling algorithms?

  When a job waits indefinitely for CPU time
• What is the Shortest Job First scheduling algorithm?

  Executes the job with the smallest total execution time
• What are Multi-Level Feedback Queues?

  Multiple queues with different priority levels
• What does the Operating System manage?

  • Memory allocation
  • CPU time
  • User interface
• What happens to pages in virtual memory?

  They are swapped in and out of RAM as needed
• How does the CPU create the illusion of multitasking?

  By scheduling applications to use the CPU