Operating Systems Flashcards
(18 cards)
What is paging (2) and what is a negative?
• Paging is the division of the RAM to make fixed sizes.
• The programs are physically divided to fit the pages on RAM.
• This means the program could be split looping conditions between pages making it inefficient.
What is segmentation? 2
• This allows different sized programs to be stored on RAM so allows for complete programs.
• This can divide programs but will make logical division making them more efficient.
What is Virtual memory? 2
• Virtual memory will be needed when the RAM is full and the user wants to open a new program.
• This method will move programs in RAM not being used onto the secondary memory to give room for the new program on RAM.
What is First Come First Serve (FCFS)?
A scheduling technique which completes tasks in the order they arrive.
What is Shortest Job First (SJF)?
A scheduling method which needs to know how long each process will take and will start from the order of shortest task to largest task.
What is Round Robin (RR)?
A scheduling method which allocates each process a fixed time slice (or quantum) and if the process is not completed in that time then it is moved to the back of the queue.
What is Shortest Remaining Time (SRT)?
A scheduling method which can suspend a process if a hire priority process joins the queue (has less ticks).
What is a Multi-level Feedback Queue (MLFQ)? 4
• This method of scheduling allows for multiple queues which have higher or lower priority.
• Each queue can use different queues like RR and SRT.
• Processes can demoted or promoted based on needs.
• This can mean a process waiting too long can be promoted or a process using too much CPU time can be demoted.
What are the 3 pre-emptive and the 2 non-pre-emptive scheduling methods.
• Pre-emptive: Round Robin (RR), Shortest Remaining Time (SRT) and Multi-level Feedback Queue (MLFQ)
• Non pre-emptive: First Come First Serve (FCFS) and Shortest Job First (SJF)
What is a Multi-tasking operating system and an example?
• A system that can run the different processes at the same time.
• Example: a laptop running a word processor and web browser.
What is a Multi-user operating system (2) and an example?
•When multiple people can use a computer at the same time.
• Will manage various permissions and access writes when they log on.
• Example: a school network
What is a distributed operating system and an example?
• Is a coordinated computer system which uses multiple computers to process a single task.
• Example: AI models or websites for businesses.
What is an embedded operating system and an example?
• They are systems which highly specialised and low powered processors and very little memory.
• Example: a washing machine
What are Real Time operating systems (2) and an example?
• A processor which have to be guaranteed to execute within a know time frame.
• Will also have fail safes built in to correct potential problems.
• Example: Autopilot systems.
What is a device driver?
Software that tells the operating system how to communicate with a device.
What is a virtual machine?
A program has the same functionality as a physical computer.
Give me 2 examples of virtual machines.
• Game emulation - tricks the code to think it is running natively
• Game development - creating games for other platforms on a pc
What does the Basic Input Output System (BIOS)?
Is responsible for loading the operating system when the computer first turns on.
