CMPS 431 (OS) Flashcards
Draw the 5 state diagram
Draw the storage hierarchy.
How do you calculate Average Time to Completion?
What is the Average Time to Completion for the example in the image provided?
(Sum of the time that the processes completed) / number of processes
Example from image
(24 + 27 + 30) / 3 = 27
How do you calculate Average Wait Time?
What is the Average Wait Time for the example in the image provided?
(Sum of initial entries into run queue) / Number of Processes
Example from the image provided
(0 + 24 + 27) / 3 = 17
What does the MS-DOS execution diagram look like at System Startup?
What about when it is running a program?
Draw the diagram for a UNIX System running multiple processes.
Which scheduling algorithm has the best response time, and why?
(not including round robin)
Shortest job first Preemptive.
Because it reevaluates to shortest job upon a new jobs arrival.
Multi Programmed batch
The computer executes jobs from a pool of jobs that have been loaded into memory
What is timesharing
Mainframe computers used time sharing to give users, located at remote terminals, the illusion that each other had the computer to themselves
Occurs when a process enters a waiting state because a resource requested is being held by another waiting process, which in turn is waiting for another resource held by another waiting process
Deadlock
How do you prevent Deadlock from happening?
Deadlock Prevention: Use of a protocol to ensure that system never enters a deadlock state. This method tries to ensure that at least one of the conditions for deadlock cannot occur by constraining how resources requests are made. (There are different strategies. This is a general explanation.)
