SLR 4 Flashcards
Operating Systems / Systems Software
What is multi-tasking?
Having more than one program running at a time
The processor allocates a small amount of time to each process and cycles between them
What is user management?
Allows multiple users to log into a single computer
What is paging?
Making physical divisions in the RAM which are at a fixed size to fit the different programs that are being ran
What is segmentation?
Logical divisions in the RAM to split them up to create space
What happens when the RAM is full?
Programs are ran on virtual memory on the hard disk
However, these programs run much slower so filling the RAM should be avoided
What is an interrupt?
An important instruction which causes current instructions to be ignored so it can be completed
What is the Interrupt Service Routine (ISR)?
It is what causes current instructions to be put placed in a stack to allow the interrupt to be completed
What does a scheduler manage?
Which process to execute next
The length of time the next process can execute for
What is First Come First Serve?
FCFS is like a supermarket queue, the first instruction to arrive goes first
What is Shortest Job First?
SJF picks the processes which take the shortest time to complete
What is Round Robin?
Each process is given an amount of time, called a time slice or time quantum
At the end of that time slice, if the process isn’t complete it’s put to the back of the queue again until it’s next time slice
What is Shortest Remaining Time?
SRT suspends some processes if more important ones are added to the queue
What is Multi-Level Feedback Queue?
MLDQ takes each builds on each standard scheduling algorithm
What is a Real-Time Operating System?
A OS used in safety-critical environments to react as fast as possible
What is the BIOS?
Basic input output system
Loads the OS when the computer first turns on
