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Worksheetsoperating system rev.
Total questions: 80
Worksheet time: 40mins
Which module gives control of the CPU to the process selected by the short-term scheduler?
dispatcher
interrupt
scheduler
none of the mentioned
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The interval from the time of submission of a process to the time of completion is termed as:
waiting time
turnaround time
response time
throughput
In which scheduling policies, context switching never takes place
FCFS
round robin
Shortest job first
Pre-empitive
Which of the following state transition is possible?
Blocked to Running
Ready to Running
Blocked to Ready
Running to Blocked
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Scheduling is done so as to :
increase CPU utilization
decrease CPU utilization
keep the CPU more idle
None of these
In priority scheduling algorithm:
CPU is allocated to the process with highest priority
CPU is allocated to the process with lowest priority
equal priority processes can not be scheduled
none of the mentioned
Match the following:
List – I
a. Multilevel feedback queue
b. FCFS
c. Shortest process next
d. Round robin scheduling
List – II
i. Time-slicing
ii. Criteria to move processes between queues
iii. Batch processing
iv. Exponential smoothing
a-i, b-iii, c-ii, d-iv
a-iv, b-iii, c-ii, d-i
a-iii, b-i, c-iv, d-i
a-ii, b-iii, c-iv, d-i
A process is selected from the ______ queue by the ________ scheduler, to be executed.
blocked, short term
wait, long term
ready, short term
ready, long term
To access the services of operating system, the interface is provided by the ___________
System calls
API
Library
Assembly instructions
Under multiprogramming, turnaround time for short jobs is usually ________ and that for long jobs is slightly ___________.
Lengthened; Shortened
Shortened; Lengthened
Shortened; Shortened
Shortened; Unchanged
Swap space is allocated _________
as a chunk of disk
separate from a file system
into a file system
all of the mentioned
Another solution to the problem of external fragmentation problem is to ____________
permit the logical address space of a process to be noncontiguous
permit smaller processes to be allocated memory at last
permit larger processes to be allocated memory at last
all of the mentioned
If relocation is static and is done at assembly or load time, compaction _________
cannot be done
must be done
must not be done
can be done
__________ is generally faster than _________ and _________
first fit, best fit, worst fit
best fit, first fit, worst fit
worst fit, best fit, first fit
none of the mentioned
The major part of swap time is _______ time.
waiting
transfer
execution
none of the mentioned
Swapping _______ be done when a process has pending I/O, or has to execute I/O operations only into operating system buffers.
must
can
must never
maybe
The size of a process is limited to the size of ________
physical memory
external storage
secondary storage
none of the mentioned
The base register is also known as the ____________
basic register
regular register
relocation register
delocation register
If the process can be moved during its execution from one memory segment to another, then binding must be ____________
delayed until run time
preponed to compile time
preponed to load time
none of the mentioned
Program always deals with ____________
logical address
absolute address
physical address
relative address
The address of a page table in memory is pointed by __________
stack pointer
page table base register
page register
program counter
The run time mapping from virtual to physical addresses is done by a hardware device called the ___________
Virtual to physical mapper
Memory management unit
Memory mapping unit
None of the mentioned
Bounded waiting implies that there exists a bound on the number of times a process is allowed to enter its critical section ___________
after a process has made a request to enter its critical section and before the request is granted
when another process is in its critical section
before a process has made a request to enter its critical section
none of the mentioned
In fixed size partition, the degree of multiprogramming is bounded by ___________
the number of partitions
the CPU utilization
the memory size
all of the mentioned
A minimum of _____ variable(s) is/are required to be shared between processes to solve the critical section problem.
one
two
three
four
Mutual exclusion implies that ____________
if a process is executing in its critical section, then no other process must be executing in their critical sections
if a process is executing in its critical section, then other processes must be executing in their critical sections
if a process is executing in its critical section, then all the resources of the system must be blocked until it finishes execution
none of the mentioned
The segment of code in which the process may change common variables, update tables, write into files is known as ____________
program
critical section
non – critical section
synchronizing
A situation where several processes access and manipulate the same data concurrently and the outcome of the execution depends on the particular order in which access takes place is called ____________
data consistency
race condition
aging
starvation
Concurrent access to shared data may result in ____________
data consistency
data insecurity
data inconsistency
none of the mentioned
The signal operation of the semaphore basically works on the basic _______ system call.
continue()
wakeup()
getup()
start()
Semaphore is a/an _______ to solve the critical section problem.
hardware for a system
special program for a system
integer variable
none of the mentioned
The wait operation of the semaphore basically works on the basic _______ system call.
stop()
block()
hold()
wait()
What are Spinlocks?
CPU cycles wasting locks over critical sections of programs
Locks that avoid time wastage in context switches
Locks that work better on multiprocessor systems
All of the mentioned
What are the two atomic operations permissible on semaphores?
wait
stop
hold
none of the mentioned
For a Hold and wait condition to prevail _________
A process must be not be holding a resource, but waiting for one to be freed, and then request to acquire it
A process must be holding at least one resource and waiting to acquire additional resources that are being held by other processes
A process must hold at least one resource and not be waiting to acquire additional resources
None of the mentioned
To ensure that the hold and wait condition never occurs in the system, it must be ensured that ____________
whenever a resource is requested by a process, it is not holding any other resources
each process must request and be allocated all its resources before it begins its execution
a process can request resources only when it has none
all of the mentioned
For non sharable resources like a printer, mutual exclusion ___________
must exist
must not exist
may exist
none of the mentioned
For sharable resources, mutual exclusion __________
is required
is not required
may be or may not be required
none of the mentioned
Deadlock prevention is a set of methods _______
to ensure that at least one of the necessary conditions cannot hold
to ensure that all of the necessary conditions do not hold
to decide if the requested resources for a process have to be given or not
to recover from a deadlock
For Mutual exclusion to prevail in the system _________
at least one resource must be held in a non sharable mode
the processor must be a uniprocessor rather than a multiprocessor
there must be at least one resource in a sharable mode
all of the mentioned
the request and release of resources are _______
command line statements
interrupts
system calls
special programs
A problem encountered in multitasking when a process is perpetually denied necessary resources is called _______
deadlock
starvation
inversion
aging
For an effective operating system, when to check for deadlock?
every time a resource request is made
at fixed time intervals
every time a resource request is made at fixed time intervals
none of the mentioned
The circular wait condition can be prevented by ___________
defining a linear ordering of resource types
using thread
using pipes
all of the mentioned
A system is in the safe state if _______
the system can allocate resources to each process in some order and still avoid a deadlock
there exist a safe sequence
all of the mentioned
none of the mentioned
What is operating system?
collection of programs that manages hardware resources
system service provider to the application programs
link to interface the hardware and application programs
all of the mentioned
In Unix, Which system call creates the new process?
fork
create
new
none of the mentioned
Process is
program in High level language kept on disk
contents of main memory
a program in execution
a job in secondary memory
Which of the following is not the state of a process ?
new
old
Waiting
Terminated
When the process issues an I/O request :
It is placed in an I/O queue
It is placed in a waiting queue
It is placed in the ready queue
It is placed in the Job queue
What is interprocess communication?
communication within the process
communication between two process
communication between two threads of same process
none of the mentioned
A thread is also called :
Light Weight Process(LWP)
Heavy Weight Process(HWP)
process
None of these
The model in which one kernel thread is mapped to many user-level threads is called :
Many to One model
One to Many model
Many to Many model
One to One model
The One to One model allows :
increased concurrency
decreased concurrency
increased or decreased concurrency
concurrency equivalent to other models
Time quantum is defined in:
shortest job scheduling algorithm
round robin scheduling algorithm
priority scheduling algorithm
multilevel queue scheduling algorithm
Consider the following table of arrival time and burst time for three processes P0, P1 and P2.
Process Arrival time Burst Time
P0 0 ms 9 ms
P1 1 ms 4 ms
P2 2 ms 9 ms
5.0 ms
4.33 ms
6.33 ms
7 ms
Consider the following set of processes, the length of the CPU burst time given in milliseconds. Assuming the below process being scheduled with the SJF scheduling algorithm.
Process: Burst time
P1: 6
P2: 8
P3: 7
P4: 3
The waiting time for process P1 is 3ms
The waiting time for process P1 is 0ms
The waiting time for process P1 is 16ms
The waiting time for process P1 is 9ms
Using Priority Scheduling algorithm, find the average waiting time for the following set of processes given with their priorities in the order: Process : Burst Time : Priority respectively .
P1 : 10 : 3 ,
P2 : 1 : 1 ,
P3 : 2 : 4 ,
P4 : 1 : 5 ,
P5 : 5 : 2.
8 milliseconds
8.2 milliseconds
7.75 milliseconds
3 milliseconds
Which of the following is a criterion to evaluate a scheduling algorithm?
CPU Utilization: Keep CPU utilization as high as possible
Throughput: number of processes completed per unit time
Waiting Time: Amount of time spent ready to run but not running
All of the above
The operating system is responsible for the following activity in connection with disk management.
Free-space management
Storage allocation
Disk scheduling
All of the above
In a time sharing operating system, when the time slot given to a process is completed, the process goes from running state to the______________.
Blocked state.
Ready state.
Terminated state.
Suspended state.
Shortest Job First executes first the job
that first entered the queue
that has been in the queue for the longest
with the least processor needs
that last entered the queue
Which of the following does not interrupt an running process
A device
Timer
Scheduler Process
Power failure
Consider the following set of processes, with the arrival times and the CPU-burst times given in milliseconds
Process : Arrival Time : Burst Time
P1 : 0 : 5
P2 : 1 : 3
P3 : 2 : 3
P4 : 4 : 1
What is the average turnaround time for these processes with the preemptive shortest remaining processing time first (SRPT) algorithm ?
5.50
5.75
6.00
6.25
Which of the following process scheduling algorithm may lead to starvation
FIFO
Round Robin
Shortest Job Next
None of the above
CPU scheduling is the basis of ___________
multiprocessor systems
multiprogramming operating systems
larger memory sized systems
none of the mentioned
Which one of the following error will be handle by the operating system?
power failure
lack of paper in printer
connection failure in the network
all of the mentioned
If a process fails, most operating system write the error information to a ______
log file
another running process
new file
none of the mentioned
When a process is in a “Blocked” state waiting for some I/O service. When the service is completed, it goes to the _______
Terminated state
Suspended state
Running state
Ready state
The FCFS algorithm is particularly troublesome for ___________
time sharing systems
multiprogramming systems
multiprocessor systems
operating systems
For real time operating systems, interrupt latency should be ____________
minimal
maximum
zero
dependent on the scheduling
The context of a process in the PCB of a process does not contain ______
the value of the CPU registers
memory-management information
the process state
context switch time
In operating system, each process has its own __________
open files
pending alarms, signals, and signal handlers
address space and global variables
all of the mentioned
The priority of a process will ______________ if the scheduler assigns it a static priority.
change
remain unchanged
depends on the operating system
none of the mentioned
in operating system, which of the following is/are CPU scheduling algorithms?
priority
Round Robin
shortest job first
all of mentioned
The operating system keeps a small table containing information about all open files called ________
system table
open-file table
file table
directory table
What will happen when a process terminates?
It is removed from all queues
It is removed from all, but the job queue
Its process control block is de-allocated
Its process control block is never de-allocated
In a multiprogramming environment ________
the processor executes more than one process at a time
the programs are developed by more than one person
more than one process resides in the memory
a single user can execute many programs at the same time
What is the main function of the command interpreter?
to get and execute the next user-specified command
to provide the interface between the API and application program
to handle the files in operating system
none of the mentioned
which of the following do not belong to queues for processes?
Job Queue
PCB Queue
Device Queue
Ready Queue
