Recent questions tagged process-scheduling / GATE Overflow for GATE CSE

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121

ISI2018-PCB-CS7
A context switch from a process $P_{old}$ to a process $P_{new}$ consists of the following steps: Step I:saving the context of $P_{old}$; Step II: running the scheduling algorithm to pick $P_{new}$; Step III: restoring the saved context of $P_{new}$. Suppose Steps ... in the order $P_1, P_2, . . . , P_k;$ each process requires exactly one CPU burst of $20$ms and no I/O burst.

A context switch from a process $P_{old}$ to a process $P_{new}$ consists of the following steps:Step I:saving the context of $P_{old}$;Step II: running the scheduling al...

akash.dinkar12

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akash.dinkar12 asked May 12, 2019

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122

Operating system swapping process
Please help me explaining this in simpler words: If we were to swap out process P1 and swap in process P2, the I/O operation might then attempt to use memory that now belongs to process P2. There are two main solutions to this ... system buffers and process memory then occur only when the process is swapped in. Note that this double buffering itself adds overhead.

Please help me explaining this in simpler words:If we were to swap out process P1 and swap in process P2, theI/O operation might then attempt to use memory that now belon...

manisha11

804 views

manisha11 asked May 9, 2019

0 votes

3 answers

123

Self Doubt CPU
In Multi-processing Operating Systems: (a) Maximum utilization of CPU can be achieved (b) Maximum throughput is achieved (c) Maximum security can be achieved (d) Not suitable for Real time Applications

In Multi-processing Operating Systems:(a) Maximum utilization of CPU can be achieved(b) Maximum throughput is achieved(c) Maximum security can be achieved(d) Not suitable...

manisha11

1.3k views

manisha11 asked May 7, 2019

0 votes

3 answers

124

self doubt - process concepts
Consider we have a cpu whose processes are scheduled using premptive priority scheduling algorithm, suppose a process of higher priority than the currently running process arrives in the ready queue, according to the algorithm the running process must be prempted, who actually does this job of interrupting the running process?

Consider we have a cpu whose processes are scheduled using premptive priority scheduling algorithm, suppose a process of higher priority than the currently running proces...

Saideepak Bejawada

945 views

Saideepak Bejawada asked Apr 9, 2019

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0 answers

125

Galvin Edition 9 Exercise 6 Question 32 (Page No. 311)
Explain why interrupt and dispatch latency times must be bounded in a hard real-time system ?

Explain why interrupt and dispatch latency times must be bounded in a hard real-time system ?

akash.dinkar12

325 views

akash.dinkar12 asked Mar 20, 2019

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0 answers

126

Galvin Edition 9 Exercise 6 Question 30 (Page No. 311)
Under what circumstances is $rate$-$monotonic$ $scheduling$ inferior to $earliest$-$deadline$-$first$ $scheduling$ in meeting the deadlines associated with processes ?

Under what circumstances is $rate$-$monotonic$ $scheduling$ inferior to $earliest$-$deadline$-$first$ $scheduling$ in meeting the deadlines associated with processes ?

akash.dinkar12

210 views

akash.dinkar12 asked Mar 20, 2019

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0 answers

127

Galvin Edition 9 Exercise 6 Question 29 (Page No. 311)
Discuss ways in which the priority inversion problem could be addressed in a real-time system. Also discuss whether the solutions could be implemented within the context of a proportional share scheduler

Discuss ways in which the priority inversion problem could be addressed in a real-time system. Also discuss whether the solutions could be implemented within the context ...

akash.dinkar12

315 views

akash.dinkar12 asked Mar 20, 2019

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0 answers

128

Galvin Edition 9 Exercise 6 Question 28 (Page No. 311)
Assume that two tasks A and B are running on a $Linux$ $system$. The nice values of A and B are $−5$ and $+5$, respectively. Using the $CFS$ scheduler as a guide, describe how the respective values of $vruntime$ vary between the two processes given each of ... A is $I/O-bound$, and B is $CPU-bound$. A is $CPU-bound$, and B is $I/O-bound$.

Assume that two tasks A and B are running on a $Linux$ $system$. The nice values of A and B are $−5$ and $+5$, respectively. Using the $CFS$ scheduler as a guide, descr...

akash.dinkar12

239 views

akash.dinkar12 asked Mar 20, 2019

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0 answers

129

Galvin Edition 9 Exercise 6 Question 27 (Page No. 310)
Consider the scheduling algorithm in the Solaris operating system for time-sharing threads. a. What is the time quantum $(in milliseconds)$ for a thread with priority 15? With priority 40? b. Assume that a thread with priority 50 ... 20 blocks for $I/O$ before its time quantum has expired. What new priority will the scheduler assign this thread

Consider the scheduling algorithm in the Solaris operating system for time-sharing threads.a. What is the time quantum $(in milliseconds)$ for a thread with priority 15? ...

akash.dinkar12

335 views

akash.dinkar12 asked Mar 20, 2019

0 votes

0 answers

130

Galvin Edition 9 Exercise 6 Question 26 (Page No. 310)
Assuming that no threads belong to the $REALTIME$_$PRIORITY$_$CLASS$ and that none may be assigned a $TIME$_$CRITICAL$ priority, what combination of priority class and priority corresponds to the highest possible relative priority in Windows scheduling?

Assuming that no threads belong to the $REALTIME$_$PRIORITY$_$CLASS$ and that none may be assigned a $TIME$_$CRITICAL$ priority, what combination of priority class and pr...

akash.dinkar12

256 views

akash.dinkar12 asked Mar 20, 2019

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0 answers

131

Galvin Edition 9 Exercise 6 Question 25 (Page No. 310)
Using the Windows scheduling algorithm, determine the numeric priority of each of the following threads. a. A thread in the $REALTIME$_$PRIORITY$_$CLASS$ with a relative priority of $NORMAL$ b. A thread in the $ABOVE$_$NORMAL$_$PRIORITY$ ... $BELOW$_$NORMAL$_$PRIORITY$_$CLASS$ with a relative priority of $ABOVE$_$NORMAL$

Using the Windows scheduling algorithm, determine the numeric priority of each of the following threads.a. A thread in the $REALTIME$_$PRIORITY$_$CLASS$ with a relative p...

akash.dinkar12

296 views

akash.dinkar12 asked Mar 20, 2019

0 votes

0 answers

132

Galvin Edition 9 Exercise 6 Question 24 (Page No. 310)
Explain the differences in how much the following scheduling algorithms discriminate in favor of short processes: $a. FCFS$ $b. RR$ $c. Multilevel feedback queues$

Explain the differences in how much the following scheduling algorithms discriminate in favor of short processes:$a. FCFS$$b. RR$$c. Multilevel feedback queues$

akash.dinkar12

866 views

akash.dinkar12 asked Mar 20, 2019

0 votes

1 answer

133

Galvin Edition 9 Exercise 6 Question 23 (Page No. 310)
Consider a preemptive priority scheduling algorithm based on dynamically changing priorities. Larger priority numbers imply higher priority. When a process is waiting for the $CPU$ (in the ready queue, but not running), its priority changes at a rate $\beta$. ... ? b. What is the algorithm that results from $\alpha$ $<$ $\beta$ $<$ $0$ ?

Consider a preemptive priority scheduling algorithm based on dynamically changing priorities. Larger priority numbers imply higher priority. When a process is waiting for...

akash.dinkar12

1.3k views

akash.dinkar12 asked Mar 20, 2019

0 votes

0 answers

134

Galvin Edition 9 Exercise 6 Question 22 (Page No. 310)
Consider a system implementing multilevel queue scheduling. What strategy can a computer user employ to maximize the amount of $CPU$ time allocated to the user’s process ?

Consider a system implementing multilevel queue scheduling. What strategy can a computer user employ to maximize the amount of $CPU$ time allocated to the user’s proces...

akash.dinkar12

241 views

akash.dinkar12 asked Mar 20, 2019

0 votes

0 answers

135

Galvin Edition 9 Exercise 6 Question 21 (Page No. 309-310)
Consider a system running ten $I/O-bound$ tasks and one $CPU-bound$ task. Assume that the $I/O-bound$ tasks issue an $I/O$ operation once for every millisecond of CPU computing and that each $I/O$ operation takes ... utilization for a round-robin scheduler when: a. The time quantum is 1 millisecond b. The time quantum is 10 milliseconds

Consider a system running ten $I/O-bound$ tasks and one $CPU-bound$ task. Assume that the $I/O-bound$ tasks issue an $I/O$ operation once for every millisecond of CPU com...

akash.dinkar12

335 views

akash.dinkar12 asked Mar 20, 2019

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0 answers

136

Galvin Edition 9 Exercise 6 Question 20 (Page No. 309)
Consider a variant of the $RR$ scheduling algorithm in which the entries in the ready queue are pointers to the $PCBs$. a. What would be the effect of putting two pointers to the same process in the ready queue ? b. What ... this scheme? c. How would you modify the basic $RR$ algorithm to achieve the same effect without the duplicate pointers?

Consider a variant of the $RR$ scheduling algorithm in which the entries in the ready queue are pointers to the $PCBs$.a. What would be the effect of putting two pointers...

akash.dinkar12

304 views

akash.dinkar12 asked Mar 20, 2019

0 votes

1 answer

137

Galvin Edition 9 Exercise 6 Question 19 (Page No. 309)
Which of the following scheduling algorithms could result in starvation ? $a. First-come$, $first-served$ $b. Shortest$ $job$ $first$ $c. Round$ $robin$ $d. Priority$

Which of the following scheduling algorithms could result in starvation ?$a. First-come$, $first-served$$b. Shortest$ $job$ $first$$c. Round$ $robin$$d. Priority$

akash.dinkar12

277 views

akash.dinkar12 asked Mar 20, 2019

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0 answers

138

Galvin Edition 9 Exercise 6 Question 18 (Page No. 309)
The nice command is used to set the nice value of a process on Linux, as well as on other UNIX systems. Explain why some systems may allow any user to assign a process a nice value $>=$ 0 yet allow only the root user to assign nice values $<$ 0.

The nice command is used to set the nice value of a process on Linux, as well as on other UNIX systems. Explain why some systems may allow any user to assign a process a ...

akash.dinkar12

212 views

akash.dinkar12 asked Mar 20, 2019

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0 answers

139

Galvin Edition 9 Exercise 6 Question 16 (Page No. 308)
Consider the following set of processes, with the length of the CPU burst given in milliseconds: $Process$ $Burst$ $Time$ $Priority$ $P_1$ $2$ $2$ $P_2$ $1$ $1$ $P_3$ $8$ $4$ $P_4$ $4$ $2$ $P_5$ ... each process for each of these scheduling algorithms ? d. Which of the algorithms results in the minimum average waiting time (over all processes)?

Consider the following set of processes, with the length of the CPU burst given in milliseconds: $Process$ $Burst$ $Time$ ...

akash.dinkar12

258 views

akash.dinkar12 asked Mar 20, 2019

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0 answers

140

Galvin Edition 9 Exercise 6 Question 15 (Page No. 308)
A variation of the round-robin scheduler is the $regressive$ $round-robin$ $scheduler$. This scheduler assigns each process a time quantum and a priority. The initial value of a time quantum is 50 milliseconds. However, every time a ... type of process ($CPU-bound$ or $I/O bound$) does the regressive round-robin scheduler favor ? Explain.

A variation of the round-robin scheduler is the $regressive$ $round-robin$ $scheduler$. This scheduler assigns each process a time quantum and a priority. The initial val...

akash.dinkar12

319 views

akash.dinkar12 asked Mar 20, 2019

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0 answers

141

Galvin Edition 9 Exercise 6 Question 12 (Page No. 307)
One technique for implementing $lottery scheduling$ works by assigning processes lottery tickets, which are used for allocating $CPU$ time.Whenever a scheduling decision has to be made, a lottery ticket is chosen at random, ... scheduler can ensure that higher-priority threads receive more attention from the $CPU$ than lower-priority threads.

One technique for implementing $lottery scheduling$ works by assigning processes lottery tickets, which are used for allocating $CPU$ time.Whenever a scheduling decision ...

akash.dinkar12

357 views

akash.dinkar12 asked Mar 20, 2019

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0 answers

142

Galvin Edition 9 Exercise 6 Question 11 (Page No. 307)
Discuss how the following pairs of scheduling criteria conflict in certain settings. a. $CPU$ utilization and response time b. Average turnaround time and maximum waiting time c. $I/O$ device utilization and $CPU$ utilization

Discuss how the following pairs of scheduling criteria conflict in certain settings.a. $CPU$ utilization and response timeb. Average turnaround time and maximum waiting t...

akash.dinkar12

251 views

akash.dinkar12 asked Mar 20, 2019

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0 answers

143

Galvin Edition 9 Exercise 6 Question 10 (Page No. 307)
Why is it important for the scheduler to distinguish $I/O-bound$ programs from $CPU-bound$ programs?

Why is it important for the scheduler to distinguish $I/O-bound$ programs from $CPU-bound$ programs?

akash.dinkar12

296 views

akash.dinkar12 asked Mar 20, 2019

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0 answers

144

Galvin Edition 9 Exercise 6 Question 9 (Page No. 307)
The traditional $UNIX$ scheduler enforces an inverse relationship between priority numbers and priorities: the higher the number, the lower the priority. The scheduler recalculates process priorities once per second using the following ... does the traditional UNIX scheduler raise or lower the relative priority of a $CPU-bound$ process?

The traditional $UNIX$ scheduler enforces an inverse relationship between priority numbers and priorities: the higher the number, the lower the priority. The scheduler re...

akash.dinkar12

473 views

akash.dinkar12 asked Mar 20, 2019

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0 answers

145

Galvin Edition 9 Exercise 6 Question 8 (Page No. 307)
Assume that an operating system maps user-level threads to the kernel using the many-to-many model and that the mapping is done through the use of $LWP$(Light Weight Processes). Furthermore, the system allows program developers to create real-time threads. Is it necessary to bind a real-time thread to an LWP?

Assume that an operating system maps user-level threads to the kernel using the many-to-many model and that the mapping is done through the use of $LWP$(Light Weight Proc...

akash.dinkar12

137 views

akash.dinkar12 asked Mar 20, 2019

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146

Galvin Edition 9 Exercise 6 Question 7 (Page No. 307)
Distinguish between $PCS$(Process Contention Scope) and $SCS$(Source Contention Scope) scheduling.

Distinguish between $PCS$(Process Contention Scope) and $SCS$(Source Contention Scope) scheduling.

akash.dinkar12

160 views

akash.dinkar12 asked Mar 20, 2019

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0 answers

147

Galvin Edition 9 Exercise 6 Question 6 (Page No. 306-307)
Suppose that a scheduling algorithm (at the level of short-term $CPU$ scheduling) favors those processes that have used the least processor time in the recent past. Why will this algorithm favor $I/O-bound$ programs and yet not permanently starve $CPU-bound$ programs ?

Suppose that a scheduling algorithm (at the level of short-term $CPU$ scheduling) favors those processes that have used the least processor time in the recent past. Why w...

akash.dinkar12

305 views

akash.dinkar12 asked Mar 20, 2019

1 votes

0 answers

148

Galvin Edition 9 Exercise 6 Question 5 (Page No. 306)
Many CPU-scheduling algorithms are parametrized. For example, the $RR$ algorithm requires a parameter to indicate the time slice. Multilevel feedback queues require parameters to define the number of queues, the scheduling algorithm for each queue, the ... . $Multilevel feedback queues$ and $FCFS$ c. $Priority$ and $FCFS$ d. $RR$ and $SJF$

Many CPU-scheduling algorithms are parametrized. For example, the $RR$ algorithm requires a parameter to indicate the time slice. Multilevel feedback queues require param...

akash.dinkar12

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akash.dinkar12 asked Mar 20, 2019

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149

Galvin Edition 9 Exercise 6 Question 4 (Page No. 306)
What advantage is there in having different time-quantum sizes at different levels of a multilevel queueing system ?

What advantage is there in having different time-quantum sizes at different levels of a multilevel queueing system ?

akash.dinkar12

276 views

akash.dinkar12 asked Mar 20, 2019

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150

Galvin Edition 9 Exercise 6 Question 3 (Page No. 306)
Suppose that the following processes arrive for execution at the times indicated. Each process will run for the amount of time listed. In answering the questions, use non preemptive scheduling, and base all decisions on the ... during this idle time, so their waiting time may increase. This algorithm could be called future-knowledge scheduling.

Suppose that the following processes arrive for execution at the times indicated. Each process will run for the amount of time listed. In answering the questions, use non...

akash.dinkar12

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akash.dinkar12 asked Mar 20, 2019

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