Systems software Flashcards
What is paging?
Paging is when memory is split up into equal sized sections known as pages.
What is segmentation?
Splitting up memory into logical sized divisions known as segments, which vary in size.
What is virtual memory?
Virtual memory is when there isn’t enough RAM left so part of the hard drive is used to act like RAM
What is the interrupt service routine?
The processor checks the contents of the interrupt register at the end of every Fetch Execute Decode cycle. If there is a high enough priority interrupt the interrupt is scheduled.
How does the Round Robin scheduling algorithm work?
Each job is given an equal section of processor time to execute, even if the job is not finished it will still move to the next job at the end of the time slice.
How does first come first serve scheduling work?
Jobs are processed in the order that they come in at, they are completed in full.
How do multilevel feedback scheduling queues work?
Jobs are given a priority level and are executed in the order of priority.
How does shortest job first scheduling work?
The shortest task is done first until completion.
How does shortest time remaining scheduling work?
The shortest job is done first, if a shorter tasks joins the queue then that will be take priority and be completed.
What are the different types of operating system?
Distributed, embedded, multitasking, multiuser, real-time.
What is a distributed OS?
A type of operating system that runs across multiple devices allowing the load to be separated across multiple computers processors
What is an embedded OS?
An embedded OS has a small range of specific tasks that can be completed, with the OS being catered towards a specific device.
What is an embedded OS?
An embedded OS has a small range of specific tasks that can be completed, with the OS being catered towards a specific device.
What is a multitasking OS?
A multitasking OS enables the user to carry out tasks seemingly simultaneously. It uses time slicing to switch between programs and applications in memory.
What is a multiuser OS?
When more than one user can use one computer, (a scheduling algorithm is used so every user gets fair time)
What is a real time OS?
A real time OS completes tasks in a guaranteed timeframe
What is applications software?
A software designed to be used by the end user to perform one specific task.
What is systems software?
Low level software that is responsible for running the computer system smoothly
What does a translator do?
A translator converts high level source code into low level object code which is ready to be executed by a computer. There are 3 different translators all of which slightly different.
What is a compiler?
Compilers translate high level language into machine code all at once.
What is an interpreter?
Interpreters translates and executes code line by line.
What is an assembler?
An assembler translates assembly code into machine code.
What different stages are used when translating code into machine code?
Lexical analysis, syntax analysis, code generation, optimisation.
What happens in lexical analysis?
Whitespace and comments are removed from code.
Keywords and variables are replaced with a token.
