System Software P3 Flashcards
What is the main purpose of an operating system?
Maximizing resource use and managing hardware/software efficiently
How does an OS manage memory?
By using static/dynamic partitioning
What is virtual memory?
Using secondary storage to simulate additional RAM
How is disk usage optimized by the OS?
By compressing files
What does the user interface in an OS do?
Hides hardware complexity and allows user interaction
What is multi-tasking in OS?
Managing multiple programs appearing to run simultaneously
What is the difference between a program and a process?
A program is written code; a process is the code being executed
Why is process scheduling important?
It ensures efficient CPU usage
What are the three common process states?
Ready
What does the ‘Ready’ state mean?
The process is waiting in the queue for CPU time
What does the ‘Running’ state mean?
The process is currently being executed
What does the ‘Blocked’ state mean?
The process is waiting for an event before continuing
What is the ‘Terminated’ state?
The process has finished execution and is removed from the queue
What is Shortest Job First scheduling?
Non-preemptive scheduling where shortest tasks are executed first
What is Round Robin scheduling?
Each process gets a fixed CPU time slice in turn
What is First Come First Served scheduling?
Processes are executed in the order they arrive
What is Shortest Remaining Time scheduling?
Preemptive scheduling based on shortest remaining execution time
What happens when an interrupt occurs?
Current process is moved to Ready; interrupt is moved to Running
What does the low-level scheduler do?
Chooses which ready process gets CPU based on priority
What does the high-level scheduler do?
Decides which process loads from backing store into Ready state
What is paging in memory management?
Dividing memory and processes into fixed-size blocks for swapping
What is a page?
A block of virtual memory
What is a page frame?
A block of main memory
What is a page table?
Tracks the mapping of pages to frames
