List of Questions:

Ques. 1. Considering 4 processes with the arrival time and the burst time requirement of the
processes the scheduler schedules the processes by interrupting the processor after every 3 units
of time and does consider the completion of the process in this iteration. The schedulers then
checks for the number of processes waiting for the processor and allots the processor to the
process but interrupting the processor after every 6 units of time and considers the completion of
the process in this iteration. The scheduler after the second iteration checks for the number of
processes waiting for the processor and now provides the processor to the process with the least
time requirement to go in the terminated state.
The inputs for the number of requirements, arrival time and burst time should be provided by the
user.

Consider the following units for reference.
Process Arrival time Burst time
P1             0              18
P2              2             23
P3             4              13
P4             13             10
Develop a scheduler which submits the processes to the processor in the above defined scenario,
and compute the scheduler performance by providing the waiting time for process, turnaround
time    for     process     and      average waiting      time     and     turnaround     time.

Ques. 2. Considering the arrival time and burst time requirement of the process the scheduler
schedules the processes by interrupting the processor after every 6 units of time and does
consider the completion of the process in this iteration. The scheduler than checks for the number
of process waiting for the processor and allots the processor to the process but interrupting the
processor every 10 unit of time and considers the completion of the processes in this iteration.
The scheduler checks the number of processes waiting in the queue for the processor after the
second iteration and gives the processor to the process which needs more time to complete than
the other processes to go in the terminated state.
The inputs for the number of requirements, arrival time and burst time should be provided by the
user.
Consider the following units for reference.
Process Arrival time Burst time
P1              0              20
P2              5              36
P3             13              19
P4             26              42
Develop a scheduler which submits the processes to the processor in the defined scenario, and
compute the scheduler performance by providing the waiting time for process, turnaround time
for process and average waiting time and turnaround time.

Ques. 3. Consider a scheduler which schedules the job by considering the arrival time of the
processes where arrival time if given as 0 is discarded or displayed as error. The scheduler
implements the shortest job first scheduling policy, but checks the queue of the processes after
the every process terminates and time taken for checking and arranging the process according to
the shortest job is 2 time unit. Compute the waiting time, turnaround time and average waiting
time and turnaround time of the processes. Also compute the total time taken by the processor to
compute all the jobs.

The inputs for the number of requirements, arrival time and burst time should be provided by the
user.

Consider the following units for reference.
Process Arrival time Burst Time
1               0              6
2              3               2
3              5               1
4              9               7
5              10              5
6              12             3
7               14             4
8              16             5
9              17             7
10             19             2
Develop a scheduler which submits the processes to the processor in the defined scenario, and
compute the scheduler performance by providing the waiting time for process, turnaround time
for process and average waiting time and turnaround time.


Ques. 4. Consider a scheduling approach which is non pre-emptive similar to shortest job next in
nature. The priority of each job is dependent on its estimated run time, and also the amount of
time it has spent waiting. Jobs gain higher priority the longer they wait, which prevents indefinite
postponement. The jobs that have spent a long time waiting compete against those estimated to
have short run times. The priority can be computed as :
Priority = 1+ Waiting time / Estimated run time
Using the data given below compute the waiting time and turnaround time for each process and
average waiting time and average turnaround time.


Process Arrival time Burst time

P1        0             20

P2        5             36

P3        13            19

P4        17            42
Ques. 5. CPU schedules N processes which arrive at different time intervals and each process is
allocated the CPU for a specific user input time unit, processes are scheduled using a preemptive
round robin scheduling algorithm. Each process must be assigned a numerical priority, with a
higher number indicating a higher relative priority. In addition to the processes one task has
priority 0. The length of a time quantum is T units, where T is the custom time considered as
time quantum for processing. If a process is preempted by a higher-priority process, the
preempted process is placed at the end of the queue. Design a scheduler so that the task with
priority 0 does not starve for resources and gets the CPU at some time unit to execute. Also
compute waiting time, turn around.

Ques. 6. Design a scheduling program that is capable of scheduling many processes that comes
in at some time interval and are allocated the CPU not more that 10 time units. CPU must
schedule processes having short execution time first. CPU is idle for 3 time units and does not
entertain any process prior this time. Scheduler must maintain a queue that keeps the order of
execution of all the processes. Compute average waiting and turnaround time.

Ques. 7. Design a scheduling program to implements a Queue with two levels:
Level 1 : Fixed priority preemptive Scheduling
Level 2 : Round Robin Scheduling
For a Fixed priority preemptive Scheduling (Queue 1), the Priority 0 is highest priority. If one
process P1 is scheduled and running , another process P2 with higher priority comes. The New
process (high priority) process P2 preempts currently running process P1 and process P1 will go
to second level queue. Time for which process will strictly execute must be considered in the
multiples of 2..
All the processes in second level queue will complete their execution according to round robin
scheduling.
Consider: 1. Queue 2 will be processed after Queue 1 becomes empty.
2. Priority of Queue 2 has lower priority than in Queue 1.

Ques. 8. Sudesh Sharma is a Linux expert who wants to have an online system where he can
handle student queries. Since there can be multiple requests at any time he wishes to dedicate a
fixed amount of time to every request so that everyone gets a fair share of his time. He will log
into the system from 10am to 12am only. He wants to have separate requests queues for students
and faculty. Implement a strategy for the same. The summary at the end of the session should
include the total time he spent on handling queries and average query time.

Ques. 9. Design a scheduler that uses a preemptive priority scheduling algorithm based on
dynamically changing priority. Larger number for priority indicates higher priority.
Assume that the following processes with arrival time and service time wants to execute (for
reference):
ProcessID              Arrival Time           Service Time
P1                     0                      4
P2                     1                      1
P3                     2                      2
P4                     3                      1

When the process starts execution (i.e. CPU assigned), priority for that process changes at the
rate of m=1.When the process waits for CPU in the ready queue (but not yet started execution),
its priority changes at a rate n=2. All the processes are initially assigned priority value of 0 when
they enter ready queue for the first time . The time slice for each process is q = 1. When two
processes want to join ready queue simultaneously, the process which has not executed recently
is given priority. Calculate the average waiting time for each process. The program must be
generic i.e. number of processes, their burst time and arrival time must be entered by user.

Ques. 10. Design a scheduler with multilevel queue having two queues which will schedule the
processes on the basis of pre-emptive shortest remaining processing time first algorithm (SROT)
followed by a scheduling in which each process will get 2 units of time to execute. Also note that
queue 1 has higher priority than queue 2. Consider the following set of processes (for
reference)with their arrival times and the CPU burst times in milliseconds.
-------------------------------------
Process Arrival-Time Burst-Time
-------------------------------------
P1           0               5
P2           1               3
P3           2                3
P4           4                1
-------------------------------------
Calculate the average turnaround time and average waiting time for each process. The input for
number of processes and their arrival time, burst time should be given by the user.

Ques. 11. Reena’s operating system uses an algorithm for deadlock avoidance to manage the
allocation of resources say three namely A, B, and C to three processes P0, P1, and P2. Consider
the following scenario as reference .user must enter the current state of system as given in this
example :
Suppose P0 has 0,0,1 instances , P1 is having 3,2,0 instances and P2 occupies 2,1,1 instances of
A,B,C resource respectively.
Also the maximum number of instances required for P0 is 8,4,3 and for p1 is 6,2,0 and finally for
P2 there are 3,3,3 instances of resources A,B,C respectively. There are 3 instances of resource A,
2 instances of resource B and 2 instances of resource C available. Write a program to check
whether Reena’s operating system is in a safe state or not in the following independent requests
for additional resources in the
current state:
    1. Request1: P0 requests 0 instances of A and 0 instances of B and 2 instances of C.
    2. Request2: P1 requests for 2 instances of A, 0 instances of B and 0 instances of C.
All the request must be given by user as input.

Ques. 12. Three students (a, b, c) are arriving in the mess at the same time. The id numbers of
these students are 2132, 2102, 2453 and the food taken time from the mess table is 2, 4 and 8
minutes. If the two students have same remaining time so it is broken by giving priority to the
students with the lowest id number. Consider the longest remaining time first (LRTF) scheduling
algorithm and calculate the average turnaround time and waiting time.

Ques. 13. Write a program for multilevel queue scheduling algorithm. There must be three
queues generated. There must be specific range of priority associated with every queue. Now
prompt the user to enter number of processes along with their priority and burst time. Each
process must occupy the respective queue with specific priority range according to its priority.
Apply Round robin algorithm with quantum time 4 on queue with highest priority range. Apply
priority scheduling algorithm on the queue with medium range of priority and First come first
serve algorithm on the queue with lowest range of priority. Each and every queue should get a
quantum time of 10 seconds. Cpu will keep on shifting between queues after every 10
seconds i.e. to apply round robin algorithm OF 10 seconds on over all structure.
Calculate Waiting time and turnaround time for every process. The input for number of
processes should be given by the user.

Ques. 14. Write a program to implement priority scheduling algorithm with context switching
time. Prompt to user to enter the number of processes and then enter their priority, burst time and
arrival time also. Now whenever operating system preempts a process and shifts cpu’s control to
some another process of higher priority assume that it takes 2 seconds for context
switching(dispatcher latency).Form a scenario, where we can give the processes are assigned
with priority where the lower integer number is higher priority and then context switch .. as the
process waits the priority of the process increase at rate of one per 2 time units of wait.
Calculate waiting time and turnaround time for each process.

Ques. 15. A uniprocessor system has n number of CPU intensive processes, each process has its
own requirement of CPU burst. The process with lowest CPU burst is given the highest priority.
A late-arriving higher priority process can preempt a currently running process with lower
priority. Simulate a scheduler that is scheduling the processes in such a way that higher priority
process is never starved due to the execution of lower priority process. What should be its
average waiting time and average turnaround time if no two processes are arriving are arriving at
same time.

Ques. 16. Design a scheduler that can schedule the processes arriving system at periodical
intervals. Every process is assigned with a fixed time slice t milliseconds. If it is not able to
complete its execution within the assigned time quantum, then automated timer generates an
interrupt. The scheduler will select the next process in the queue and dispatcher dispatches the
process to processor for execution. Compute the total time for which processes were in the queue
waiting for the processor. Take the input for CPU burst, arrival time and time quantum from the
user.

Ques. 17. Design a scheduler following non-preemptive scheduling approach to schedule the
processes that arrives at different units and having burst time double the arrival time. Scheduler
selects the process with largest burst time from the queue for the execution. Process is not being
preempted until it finishes its service time. Compute the average waiting time and average
turnaround time. What should be the average waiting time if processes are executed according to
Shortest Job First scheduling approach with the same attribute values.

Ques. 18. Ten students (a,b,c,d,e,f,g,h,i,j) are going to attend an event. There are lots of gift
shops, they all are going to the gift shops and randomly picking the gifts. After picking the gifts
they are randomly arriving in the billing counter. The accountant gives the preference to that
student who has maximum number of gifts. Create a C or Java program to define order of billed
students?

Ques. 19. There are 5 processes and 3 resource types, resource A with 10 instances, B with 5
instances and C with 7 instances. Consider following and write a c code to find whether the
system is in safe state or not?

Available Processes Allocation           Max
A B C               A B C              A  B        C
3 3 2        P0     0 1 0              7  5        3
             P1     2 0 0              3  2        2
             P2     3 0 2              9  0        2
             P3     2 1 1              2  2        2
             P4     0 0 2              4  3        3


Ques. 20. Consider that a system has P resources of same type. These resources are shared by Q
processes time to time. All processes request and release the resources one at a time. Generate a
solution to demonstrate that, the system is in safe state when following conditions are satisfied.
Conditions:

   1. Maximum resource need of each process is between 1 and P.
   2. Summation of all maximum needs is less than P+Q

Ques. 21. Consider a scenario of demand paged memory. Page table is held in registers. It takes
8 milliseconds to service a page fault if an empty page is available or the replaced page is not
modified and 20 milliseconds if the replaced page is modified. Memory access time is 100
nanoseconds. Assume that the page to be replaced is modified 70 percent of the time. Generate a
solution to find maximum acceptable page-fault rate for access time that is not more than 200
nanoseconds.

Ques. 22. Consider following and Generate a solution to find whether the system is in safe state
or not?

 Available       Processes       Allocation                   Max
A B C D                      A   B     C D         A      B         C   D
1 5 2 0             P0       0   0     1 2         0      0         1   2
                    P1       1   0     0 0         1      7         5   0
                    P2       1   3     5 4         2      3         5   6
                    P3       0   6     3 2         0      6         5   2
                    P4       0   0     1 4         0      6         5   6


Ques. 23. Write a multithreaded program that implements the banker's algorithm. Create n
threads that request and release resources from the bank. The banker will grant the request only
if it leaves the system in a safe state. It is important that shared data be safe from concurrent
access. To ensure safe access to shared data, you can use mutex locks.
Ques 24. Design a scheduling program to implements a Queue with two levels:
Level 1 : Fixed priority preemptive Scheduling
Level 2 : Round Robin Scheduling
For a Fixed priority preemptive Scheduling (Queue 1), the Priority 0 is highest priority. If one
process P1 is scheduled and running, another process P2 with higher priority comes. The New
process (high priority) process P2 preempts currently running process P1 and process P1 will go
to second level queue. Time for which process will strictly execute must be considered in the
multiples of 2.

All the processes in second level queue will complete their execution according to round
robin scheduling.
Consider: 1. Queue 2 will be processed after Queue 1 becomes empty.
   3. Priority of Queue 2 has lower priority than in Queue 1.
Ques 25. Write a program for multilevel queue scheduling algorithm. There must be three queues
generated. There must be specific range of priority associated with every queue. Now prompt the
user to enter number of processes along with their priority and burst time. Each process must
occupy the respective queue with specific priority range according to its priority. Apply Round
Robin algorithm with quantum time 4 on queue with highest priority range. Apply priority
scheduling algorithm on the queue with medium range of priority and First come first serve
algorithm on the queue with lowest range of priority. Each and every queue should get a
quantum time of 10 seconds. CPU will keep on shifting between queues after every 10 seconds.
Ques 26. Write a program in C which will accept5 positive integers as command line
arguments. Performs check whether there are 5 arguments or not. If number of arguments are
lesser or greater than 5 then it will print a relevant message to the user. If you enter 5 positive
integers from command line then the program treat those argument as required CPU bust for
P1, P2, P3, P4, andP5 process and calculate average waiting time and average turnaround
time. Consider used scheduling algorithm as FCFS and same arrival time for all the
processes.

Ques 27. Write a program in C which reads input CPU bursts from a the first line of a text file
named as CPU_BURST.txt. Validate the input numbers whether the numbers are positive
integers or not. Consider the numbers as CPU burst. If there are 5 positive integers in the first
line of the text file then the program treat those argument as required CPU bust for P1, P2, P3,
P4, and P5 process and calculate average waiting time and average turnaround time. Consider
used scheduling algorithm as SJF and same arrival time for all the processes.


Ques 28. Given five memory partitions of 100 KB, 500 KB, 200 KB, 300 KB, and 600 KB
(in order), how would each of the first-fit, best-fit, and worst-fit algorithms place processes
of 212 KB, 417 KB, 112 KB, and 426 KB (in order)? Write a program in C which will print
the mapping of processes with memory partitions for both the algorithms.(for conceptual
clarity refer the textbook)



Ques 29. Write a C program to create a page table for a program of 5MB. Consider page size
as 2KB. Assign frame numbers randomly in page table. (for conceptual clarity refer the
textbook)


Ques 30. Write a C program to solve the following problem:
Suppose that a disk drive has 5,000 cylinders, numbered 0 to 4999. The drive is currently
serving a request at cylinder143, and the previous request was at cylinder 125. The queue of
pending requests, in FIFO order,is:


86, 1470, 913, 1774, 948, 1509, 1022, 1750, 130


Starting from the current head position, what is the total distance (in cylinders) that the disk
arm moves to satisfy all the pending requests for each of the FCFS disk-scheduling
algorithms? (for conceptual clarity refer the textbook)

Q31. Write a C program to solve the following problem:

Suppose that a disk drive has 5,000 cylinders, numbered 0 to 4999. The drive is currently
serving a request at cylinder143, and the previous request was at cylinder 125. The queue of
pending requests, in FIFO order is:

86, 1470, 913, 1774, 948, 1509, 1022, 1750, 130

Starting from the current head position, what is the total distance (in cylinders)that the disk
arm moves to satisfy all the pending requests for each of the SSTF disk-scheduling
algorithms? (for conceptual clarity refer the textbook)

Q32. Write a C program to solve the following problem:

Suppose that a disk drive has 5,000 cylinders, numbered 0 to 4999. The drive is currently
serving a request at cylinder143, and the previous request was at cylinder 125. The queue of
pending requests, in FIFO order is:

86, 1470, 913, 1774, 948, 1509, 1022, 1750, 130

Starting from the current head position, what is the total distance (in cylinders) that the disk
arm moves to satisfy all the pending requests for each of the SCAN disk-scheduling
algorithms?

Q33. Write a C program to solve the following problem:

Suppose that a disk drive has 5,000 cylinders, numbered 0 to 4999. The drive is currently
serving a request at cylinder143, and the previous request was at cylinder 125. The queue of
pending requests, in FIFO order is

86, 1470, 913, 1774, 948, 1509, 1022, 1750, 130
Starting from the current head position, what is the total distance (in cylinders) that the disk
arm moves to satisfy all the pending requests for each of the CSCAN disk-scheduling
algorithms?

Q34. Write a C program to solve the following problem:

Suppose that a disk drive has 5,000 cylinders, numbered 0 to 4999. The drive is currently
serving a request at cylinder143, and the previous request was at cylinder 125. The queue of
pending requests, in FIFO order is:


86, 1470, 913, 1774, 948, 1509, 1022, 1750, 130


Starting from the current head position, what is the total distance (in cylinders) that the disk
arm moves to satisfy all the pending requests for each of the LOOK disk-scheduling
algorithms?



Q35. Write a C program to solve the following problem:

Suppose that a disk drive has 5,000 cylinders, numbered 0 to 4999. The drive is currently
serving a request at cylinder143, and the previous request was at cylinder 125. The queue of
pending requests in FIFO order is:


86, 1470, 913, 1774, 948, 1509, 1022, 1750, 130


Starting from the current head position, what is the total distance (in cylinders)that the disk
arm moves to satisfy all the pending requests for each of the C-LOOK disk-scheduling
algorithms?


Q36. Consider the following set of processes, with the length of the CPU burst given in
milliseconds:
Schedule the processes using SJF scheduling, and print the outlook of Gant Chart on the
computer screen.


Example:


           |________________|_________________|___________________________|___|




Q37. Consider the following four processes, with the length of the CPU burst given in
milliseconds




Write a C program to calculate average waiting time using shortest-remaining-time-first
scheduling.


Q38. consider the following set of processes, assumed to have arrived at time 0, in the
orderP1, P2, • • • , P5, with the length of the CPU burst given in milliseconds:




Write a C program to schedule the processes using priority scheduling and calculate
average waiting time. Consider Lower the number higher the priority.


Q39.Thereare five processes in the system. All five processes arrive at time 0, in the order
given, with the length of the CPU burst given in milliseconds:
Write a C program which will incorporate SFJ scheduling and print the ending time of
process Pi.

Q40. Consider the following set of processes, with the length of the CPU burst given in
milliseconds:




The processes are assumed to have arrived in the order Pi, P2, P3, P4, P5, all at time 0. Write a C
program to calculate the turnaround time of each process by incorporating SJF scheduling.

Q41. Write a program which incorporate Peterson's solution for synchronizing two processes
those are simultaneously trying to write on a shared file named as File.txt. (use system calls
only)


Q42. The Sleeping-Barber Problem. A barbershop consists of a waiting room with n chairs
and a barber room with one barber chair. If there are no customers to be served the barber
goes to sleep. If a customer enters the barbershop and all chairs are occupied then the
customer leaves the shop. If the barber is busy but chairs are available, then the customer sits
in one of the free chairs. If the barber is asleep, the customer wakes up the barber. Write a
program to coordinate the barber and the customers.
Q43. Develop a scheduler which submits processes to the processor in the following
scenario and compute the scheduler performance by providing the waiting time for
process, turnaround time for process and average waiting time and turnaround time.

Considering the arrival time and the burst time requirement of the processes the scheduler
schedules the processes by interrupting the processor after every 3units of time and does
consider the completion of the process in this iteration. The scheduler then checks for the
number of processes waiting for the processor and allots the processor to the process but
interrupting the processor after every 6 units of time and considers the completion of the
process in this iteration. The scheduler after these iteration checks for the number of processes
waiting for the processor and now provides the processor to the process with the least time
requirement to go in the terminated state.

The inputs for the number of requirements, arrival time and burst time should be
provided by the user.

Q44. Develop a scheduler which submits processes to the processor in the following scenario
and compute the scheduler performance by providing the waiting time for process, turnaround
time for process and average waiting time and turnaround time.

Considering the arrival time and burst time requirement of the process the scheduler schedules
the processes by interrupting the processor after every 6 units of time and does consider the
completion of the process in this iteration. The scheduler then checks for the number of
process waiting for the processor and allots the processor to the process but interrupting the
processor every 10 unit of time and considers the completion of the processes in this iteration.
The scheduler checks the number of processes waiting in the queue for the processor after the
second iteration and gives the processor to the process which needs more time to complete
than the other processes to go in the terminated state.

The inputs for the number of requirements arrival time and burst time should be
provided by the user.

Q45.If a teacher is being served and during the period when he is being served another
teacher comes, then that teacher would get the service next. This process might continue
leading to increase in waiting time of students. Write a C program to ensure in your program
that the waiting time of students is minimized. Assume values of arrival time, burst time by
your own.
Q46.Consider a scheduling approach which is nonpre-emptive similar to shortest job next in
nature. The priority of each job is dependent on its estimated run time and also the amount of
time it has spent waiting. Jobs gain higher priority the longer they wait which prevents
indefinite postponement. The jobs that have spent a long time waiting compete against those
estimated to have short run times. The priority can be computed as :

Priority =1+ Waiting time / Estimated run time

Write a C program which will use the data given below and compute the waiting time and
turnaround time for each process and average waiting time and average turnaround time.


Process                            Arrival time                        Burst time

P1                                 0                                   20

P2                                 5                                   36

P3                                 13                                  19

P4                                 17                                  42



Q47. For SJF algorithm,

(i) We randomly generate the number of jobs. There must be a limit on the number of jobs in a
system. (ii)The execution time of the generated jobs is also not known. Here, we are
generating the CPU burst of each job making use of the past history.

(iii)All the jobs are then arranged in a queue where searching is done to find the one with the
least CPU burst. There may be two jobs in queue with the same execution time then FCFS
approach is to be performed.

Case a) If the algorithm is non-preemptive in nature, then the newly arriving job is to be added
to the job queue even though it is of lesser execution time than the one running on the
processor.

Case b) Otherwise pre-emption is performed.


Assume values of arrival time, burst time (when required) by your own.
Q48.CPU schedules N processes which arrive at different time intervals and each process is
allocated


The CPU for a specific user input time unit, processes are scheduled using a preemptive round
robin scheduling algorithm. Each process must be assigned a numerical priority, with a higher
number indicating a higher relative priority. In addition to the processes one task has priority 0.
The length of a time quantum is T units, where T is the custom time considered as time quantum
for processing .If a process is pre-empted by a higher priority process, the pre-empted process is
placed at the end of the queue. Design a scheduler so that the task with priority 0 does not starve
for resources and gets the CPU at some time unit to execute. Also compute waiting time, turn
around.

Q49.Design a scheduling program that is capable of scheduling many processes that comes in at
some time interval and are allocated the CPU not more than10 time units. CPU must schedule
processes having short execution time first. CPU is idle for 3 time units and does not entertain
any process prior this time. Scheduler must maintain a queue that keeps the order of execution of
all the processes. Compute average waiting and turnaround time.

Q50. Design a scheduling program to implements a Queue with two levels:


Level 1: Fixed priority pre-emptive Scheduling

Level 2: Round Robin Scheduling

For a Fixed priority preemptive Scheduling (Queue1), thePriority 0 is highest priority. If one
process P1 is scheduled and running, another process P2 with higher priority comes. The New
process (high priority) process P2 preempts currently running process P1 and process P1will go
to second level queue. Time for which process will strictly execute must be considered in the
multiples of 2.

All the processes in second level queue will complete their execution according to round robin
scheduling.

Consider: 1. Queue 2 will be processed after Queue 1 becomes empty.

2. Priority of Queue 2 has lower priority than in Queue 1.

Q51. Design a scheduler that uses a pre-emptive priority scheduling algorithm based on
dynamically changing priority. Larger number for priority indicates higher priority.
Assume that the following processes with arrival time and service time wants to execute (for
reference):

Process        AT       Service Time (BT)

P1             0              4
P2             1              1
P3             2              2
P4             3              1
When the process starts execution (i.e.CPU assigned) priority for that process changes at the
rate of m=1. When the process waits for CPU in the ready queue (but not yet started
execution), its priority changes at a rate n=2. All the processes are initially assigned priority
value of 0 when they enter ready queue for the first time. The time slice for each process is
q=1. When two processes want to join ready queue simultaneously, the process which has not
executed recently is given priority. Calculate the average waiting time for each process. The
program must be generic i.e. number of processes, their burst time and arrival time must be
entered by user.

Q52.Design a scheduler with multilevel queue having two queues which will schedule the
processes on the basis of pre-emptive shortest remaining processing time first algorithm
(SROT) followed by a scheduling in which each process will get 2 units of time to execute.
Also note that queue 1 has higher priority than queue2. Consider the following set of
processes (for reference) with the arrival times and the CPU burst times in milliseconds.

Pro       AT       BT


P1         0        5

P2         1        3

P3         2        3

P4         4        1


Calculate the average turnaround time and average waiting time for each process. The input for
number of processes and their arrival time, burst time should be given by the user.
Q53.consider a system with five processes P0 through P4 and three resource types A, B and C.
Resource type A has10 instances, resource type B has 5 instances, and resource type C has 7
instances.

Suppose that, at time T0, the following snap shot of the system has been taken




Implement the Banker's algorithm to claim that the system is in safe state or not?

Q54. ASSIGNMENT COMPLETION PROBLEM

There are 3 student processes and 1 teacher process. Students are supposed to do their
assignments and they need 3 things for that-pen, paper and question paper. The teacher has an
infinite supply of all the three things. One students has pen, another has paper and another has
question paper. The teacher places two things on a shared table and the student having the
third complementary thing makes the assignment and tells the teacher on completion. The
teacher then places an other two things out of the three and again the student having the third
thing makes the assignment and tells the teacher on completion. This cycle continues. WAP to
synchronise the teacher and the students.