Deck 9: Uniprocessor Scheduling

Question 1

Which of the following scheduling policies allow the O/S to interrupt the currently running process and move it to the Ready state?

A) FIFO
B) FCFS
C) non-preemptive
D) preemptive

Answer 1

D

Question 2

Round robin is particularly effective in a general purpose time sharing system or transaction processing system.

Answer 2

True

Question 3

The objective of a fair-share scheduler is to monitor usage to give fewer resources to users who have had more than their fair share, and more to those who have had less than their fair share.

Answer 3

True

Question 4

In fair share scheduling each user is assigned a weighting of some sort that defines that user's share of system resources as a fraction of the total usage of those resources.

Question 5

The main objective of long-term scheduling is to allocate processor time in such a way as to optimize one or more aspects of system behavior.

Question 6

In most interactive operating systems adequate response time is the critical requirement.

Question 7

The __________ specifies the instants in time at which the selection function is exercised.

A) decision mode
B) medium-term scheduling
C) ready state
D) TAT

Question 8

In a multiprogramming system multiple processes exist concurrently in main memory.

Question 9

The medium-term scheduler is invoked whenever an event occurs that may lead to the blocking of the current process or that may provide an opportunity to preempt a currently running process in favor of another.

Question 10

The _________ determines which process, among ready processes, is selected next for execution.

A) decision mode
B) selection function
C) TAT
D) long-term scheduler

Question 11

First-come-first-served (FCFS) is a simple scheduling policy that tends to favor I/O bound processes over processor bound processes.

Question 12

A disadvantage of simulation is that results for a given run only apply to that particular collection of processes under that particular set of assumptions.

Question 13

One problem with a pure priority scheduling scheme is that lower-priority processes may suffer starvation.

Question 14

In the Highest Response Ration Next (HRRN) scheduling policy, longer jobs are favored because they yield a larger ratio from the smaller denominator in the equation.

Question 15

FCFS performs much better for short processes than long ones.

Question 16

The traditional UNIX scheduler employs multilevel feedback using round robin within each of the priority queues.

Question 17

The key to multiprogramming is scheduling.

Question 18

The decision as to which available process will be executed by the processor:

A) long-term scheduling
B) I/O scheduling
C) medium-term scheduling
D) short-term scheduling

Question 19

Scheduling affects the performance of the system because it determines which processes will wait and which will progress.

Question 20

The traditional UNIX scheduler divides processes into fixed bands of priority levels, with the highest priority band being the _________ .

A) user process band
B) swapper band
C) file manipulation band
D) utilization band

Question 21

Response time in an interactive system is an example of:

A) user-oriented criteria for long-term scheduling policies
B) system-oriented criteria for short-term scheduling policies
C) system-oriented criteria for long-term scheduling policies
D) user-oriented criteria for short-term scheduling policies

Question 22

The decision as to which process' pending I/O request shall be handled by an available I/O device:

A) long-term scheduling
B) short-term scheduling
C) I/O scheduling
D) medium-term scheduling

Question 23

__________ considers the execution history of a related group of processes along with the individual execution history of each process in making scheduling decisions.

A) TAT
B) HRRN
C) FSS
D) FCFS

Question 24

In terms of the queuing model, __________ is the total time that the item spends in the system (waiting time plus service time).

Question 25

_________ is the elapsed time between the submission of a request until the response begins to appear as output.

Question 26

The _________ scheduler determines which programs are admitted to the system for processing.

Question 27

Typically, the swapping-in function for processes is based on the need to manage __________ .

A) the degree of multiprogramming
B) I/O requirements
C) process priorities
D) virtual memory

Question 28

A common technique for predicting a future value on the basis of a time series of past values is __________ .

Question 29

Giving each process a slice of time before being preempted is a technique known as __________ .

Question 30

In the case of the __________ policy, the scheduler always chooses the process that has the shortest expected remaining processing time.

A) SRT
B) FCFS
C) SPN
D) HRRN

Question 31

The strategy that schedules processes based on their group affiliation is generally referred to as _________ .

A) shortest process next
B) fair share scheduling
C) queuing analysis
D) simulation modeling

Question 32

The simplest scheduling policy is __________ .

Question 33

The __________ approach means that the operating system allocates the processor to a process and when the process blocks or is preempted, feeds it back into one of several priority queues.

Question 34

The operating system must make _________ types of scheduling decisions with respect to the execution of processes.

A) six
B) four
C) five
D) three

Question 35

This is a decision whether to add a new process to the set of processes that are currently active:

A) short-term scheduling
B) long-term scheduling
C) medium-term scheduling
D) I/O scheduling

Question 36

The aim of __________ is to assign processes to be executed by the processor or processors over time, in a way that meets system objectives, such as response time, throughput, and processor efficiency.

Question 37

__________ scheduling is part of the swapping function.

Question 38

This is a decision whether to add a process to those that are at least partially in main memory and therefore available for execution:

A) long-term scheduling
B) I/O scheduling
C) short-term scheduling
D) medium-term scheduling

Question 39

The __________ scheduler executes most frequently and makes the fine-grained decision of which process to execute next.

Question 40

A risk with _________ is the possibility of starvation for longer processes, as long as there is a steady supply of shorter processes.

A) SRT
B) SPN
C) FIFO
D) FCFS

Question 41

The traditional UNIX scheduler, such as those used in SVR3 and 4.3 BSD UNIX systems, divides processes into fixed __________ of priority levels.

Question 42

The need to know or estimate required processing times for each process, the starvation of longer processes, and the lack of preemption are all difficulties with the __________ scheduling technique.

Question 43

Response time and throughput are examples of __________ criteria for short term scheduling.

Question 44

A scheduling mechanism that requires no prior knowledge of process length, yet can nevertheless favor shorter jobs, is known as the __________ scheduling mechanism.

Question 45

_________ is a scheduling policy in which the process with the shortest expected processing time is selected next, and if a shorter process becomes ready in the system, the currently running process is preempted.