Topic 2

• What does the term 'operating system' refer to?


  A collection of programs that provide an interface between the user and computer
• Why are operating systems essential for devices like laptops and mobile phones?


  They enable user communication with the computer and manage memory and resources
• Name two popular desktop operating systems.

  Windows and macOS
• Name two popular mobile phone operating systems.

  iOS and Android
• What are the key features provided by operating systems?


  • Memory management (paging, segmentation, virtual memory)
  • Resource management (scheduling)
  • File management (moving, editing, deleting files and folders)
  • Input/Output management (device drivers)
  • Interrupt management
  • Utility software (disk defragmenter, backup, formatting)
  • Security (firewall)
  • User interface

  
• What is the role of memory management in an operating system?


  To share computer memory fairly between multiple programs and applications
• What is paging in memory management?


  Memory is split into equal-sized sections known as pages
• How does segmentation differ from paging?


  Segmentation splits memory into logical divisions of varying sizes
• What is virtual memory used for?


  To use a section of the hard drive as RAM when main memory is insufficient
• What is disk thrashing?


  When the computer freezes due to excessive page swapping between hard disk and main memory
• What are interrupts in an operating system?


  Signals generated by software or hardware indicating a process needs attention
• How does the operating system manage interrupts?


  By storing them in a priority queue within an interrupt register
• What is the purpose of the Interrupt Service Routine (ISR)?


  To ensure interrupts are serviced fairly by the processor
• What does the term 'operating system' refer to?


  A collection of programs that provide an interface between the user and computer
• Why are operating systems essential for devices like laptops and mobile phones?


  They enable user communication with the computer and manage memory and resources
• Name two popular desktop operating systems.

  Windows and macOS
• Name two popular mobile phone operating systems.

  iOS and Android
• What features do operating systems provide?

  • Memory management (paging, segmentation, virtual memory)
  • Resource management (scheduling)
  • File management (moving, editing, deleting files and folders)
  • Input/Output management (device drivers)
  • Interrupt management
  • Utility software (disk defragmenter, backup, formatting)
  • Security (firewall)
  • User interface
• What is the role of memory management in an operating system?


  To share computer memory fairly between multiple programs and applications
• What is paging in memory management?


  Memory is split into equal-sized sections known as pages
• How does segmentation differ from paging?


  Segmentation splits memory into logical divisions of varying sizes
• What is virtual memory used for?


  To use a section of the hard drive as RAM when main memory is insufficient
• What is disk thrashing?


  When pages are swapped too frequently between the hard disk and main memory
• What are interrupts in an operating system?


  Signals generated by software or hardware indicating a process needs attention
• How does the operating system manage interrupts?


  By storing them in order of priority within a priority queue
• What is the purpose of the Interrupt Service Routine (ISR)?


  To ensure interrupts are serviced fairly by the processor
• What happens when an interrupt is detected during a Fetch-Decode-Execute cycle?


  The current contents of special purpose registers are transferred into a stack
• What is the role of the scheduling algorithm in an operating system?


  To ensure all jobs receive a fair amount of processing time
• What are the two types of scheduling algorithms?

  1. Pre-emptive: Jobs are actively started and stopped by the OS.
  2. Non pre-emptive: Jobs are left alone until completed.
• Describe the Round Robin scheduling algorithm.


  Each job is given a time slice to execute, rotating through the queue
• What is the First Come First Served (FCFS) scheduling algorithm?


  Jobs are processed in the order they entered the queue
• What is the Multilevel Feedback Queues scheduling algorithm?


  It uses multiple queues ordered by different priorities
• What is the Shortest Job First scheduling algorithm?


  Jobs are ordered by the time required for completion, with shorter jobs first
• What is the Shortest Remaining Time scheduling algorithm?


  Jobs are ordered by the time left for completion, with the least time first
• What are the types of operating systems?


  • Distributed: Runs across multiple devices
  • Embedded: Specific tasks for specific devices
  • Multi-tasking: Allows simultaneous task execution
  • Multi-user: Multiple users on one computer
  • Real Time: Performs tasks within a guaranteed time frame
• What is the Basic Input Output System (BIOS)?


  The first program that runs when a computer system is switched on
• What does the BIOS do during startup?


  Runs key tests before the operating system is loaded into memory
• What is the Power-on Self Test (POST)?


  A test that ensures all hardware is correctly connected and functional
• Why is the BIOS critical to the computer system?


  It ensures the operating system can be loaded into RAM after checks
• What are device drivers?


  Programs that allow the operating system to interact with hardware