OPERATING SYSTEMA fault simulation testing technique is
III. A block hole in a DFD is a data store with only inbound flows IV Multivalued dependency among attribute is checked at 3 NF level.
V. An entity-relationship diagram is a tool to represent event model.
A I, II, II B II, III, IV C III, IV, V D II, IV, V Answer A _________________________________________________________________________________ __________
The completion order of the 3 processes under the policies FCFS and RR2 (round robin scheduling with CPU quantum of 2 time units) are
A FCFS: P1, P2, P3 RR2: P1, P2, P3 B FCFS: P1, P3, P2 RR2: P1, P3, P2 C FCFS: P1, P2, P3 RR2: P1, P3, P2 D FCFS: P1, P3, P2 RR2: P1, P2, P3 Answer C _________________________________________________________________________________ __________
Indefinite blocking is called
A Deadlock B Starvation C Both a and b D None of these Answer B _________________________________________________________________________________ __________
A solution to the critical section problem must satisfy which requirements? A Bounded waiting, monitor and relative speed
B Semaphores, monitor and prevention of deadlock C Signal, wait and continue
D Mutual exclusion, progress and bounded waiting Answer D
_________________________________________________________________________________ __________
_____________ is one preemptive scheduling algorithm. A Shortest job first
B Round robin C Priority based D Shortest job next
It is not possible to have a deadlock involving only a single process. Why? A This holds mutual exclusion, hold-and-wait and non-preemption
B This follows directly from the hold-and-wait condition C Because single process not always in safe state
D None of the above Answer B
_________________________________________________________________________________ __________
A Dead-lock in an Operating System is A Desirable process
B Undesirable process C Definite waiting process D All of the above
Answer C
_________________________________________________________________________________ __________
Which of the following approaches do not require knowledge of the system state? A Deadlock detection
B Deadlock prevention C Deadlock avoidance D None of the above
Answer D
_________________________________________________________________________________ __________
The simplest way to break a deadlock is to A Preempt a resource
B Rollback
C Kill one of the processes D Lock one of the processes
Answer C
_________________________________________________________________________________ __________
Three concurrent processes X, Y, and Z execute three different code segments that access and update certain shared variables. Process X executes the P operation (i.e., wait) on semaphores a, b and c; process Y executes the P operation on semaphores b, c and d; process Z executes the P operation on semaphores c, d, and a before entering the respective code segments. After completing the execution of its code segment, each process invokes the V operation (i.e., signal) on its three semaphores. All semaphores are binary semaphores initialized to one. Which one of the following represents a deadlock- free order of invoking the P operations by the processes? A X : P (a ) P (b) P (c ) Y : P (b ) P (c) P (d) Z : P (c ) P (d) P (a) B X : P (b ) P (a) P (c ) Y : P (b ) P (c) P (d) Z : P (a ) P (c ) P (d) C X : P (b ) P (a) P (c ) Y : P (c ) P (b) P (d) Z : P (a ) P (c ) P (d) D X : P (a ) P (b) P (c ) Y : P (c ) P (b) P (d) Z : P (c ) P (d) P (a) Answer B _________________________________________________________________________________ __________
The purpose of a Memory Management Unit is to ___________ . A Perform run-time mapping from virtual to physical addresses B Ensure protection of the memory space allocated to every process C Both A and B are correct responses
D None of these responses is correct Answer A
___________________________________________________________________________________ ________
In virtual memory systems, Dynamic address translation A Is the hardware necessary to implement paging
B Stores pages at a specific location on disk C Is useless when swapping is used
D Is part of the operating system paging algorithm Answer A
___________________________________________________________________________________ ________
Assertion(A): Bit maps are not often used in memory management.
Reason(R): Searching a bitmap for a run of given length is a slow operation. A Both (A) and (R) are true and (R) is correct explanation for (A)
B Both(A) and (R) are true but (R) is not correct explanation for (A) C (A) is true (R) is false
D (A) is false (R) is true Answer A
___________________________________________________________________________________ ________
The performance of cache memory is frequently measured in terms of a quantity called
A Bit ratio B Nor ratio C No ratio D Hit ratio Answer D ___________________________________________________________________________________ ________
In which of the following page replacement policies Balady’s anomaly occurs?
A FIFO B LRU C LFU D NRU Answer A ___________________________________________________________________________________ ________
Suppose it takes 100 ns to access a page table and 20 ns to access associative memory with a 90% hit rate, the average access time equals:
A 20 ns B 28 ns C 90 ns D 100 ns Answer B ___________________________________________________________________________________ ________
Moving process from main memory to disk is called
A Scheduling B Catching C Swapping D Spooling Answer C ___________________________________________________________________________________ ________ Virtual memory is
A related to virtual reality B a form of ROM
C a form of RAM D None of the above
Answer C
___________________________________________________________________________________ ________
___________ is a technique of temporarily removing inactive programs from the memory of computer system. A Swapping B Spooling C Semaphore D Scheduler Answer A ___________________________________________________________________________________ ________
Fragmentation of the file system
A Occurs only if file system is used improperly B Can always be prevented
C Can be temporarily removed by compaction D Is the characteristic of all the file systems
The size of the virtual memory depends on the size of the
A Data bus
B Main memory
C Address bus
D None of the above Answer C
______________________________________________________________________________________ _____
Variable partition memory management technique with compaction results in A Reduction of fragmentation
B Minimal wastage C Segment sharing D None of the above
Answer A
______________________________________________________________________________________ _____
Loading operating system from secondary memory to primary memory is called
A Compiling B Booting C Refreshing D Reassembling Answer B ______________________________________________________________________________________ _____
Paging is a memory management scheme that ___________________. A Permits the logical address space of a process to be noncontiguous B Avoids external fragmentation and the need for compaction
C Solves the considerable problem of fitting memory chunks of fixed sizes onto the backing store D All of the above
Answer B
______________________________________________________________________________________ _____
A static partitioned memory management system has a total of six partitions. If one is allocated to the operating system, this will allow a total of
A Five user jobs B Six user jobs
C Thirty-two user jobs D Thirty-six user jobs
Answer A
______________________________________________________________________________________ _____
Consider the virtual page reference string 1, 2, 3, 2, 4, 1, 3, 2, 4, 1
on a demand paged virtual memory system running on a computer system that has main memory size of 3 page frames which are initially empty. Let LRU, FIFO and OPTIMAL denote the number of page faults under the corresponding page replacement policy. Then
A OPTIMAL < LRU < FIFO B OPTIMAL < FIFO < LRU
C OPTIMAL = LRU
D OPTIMAL = FIFO
Answer B
______________________________________________________________________________________ _____
Virtual memory can be implemented with
A Segmentation
B Paging
C None
D All of the above Answer D
______________________________________________________________________________________ _____
On a disk with 1000 cylinders (0 to 999) find the number of tracks, the disk arm must move to satisfy all the requests in the disk queue. Assume the last request service was at track 345 and the head is moving toward track 0. The queue in FIFO order contains requests for the following tracks : 123, 874, 692, 475, 105, 376
(Assume SCAN algorithm)
A 2013 B 1219 C 1967 D 1507 Answer B ______________________________________________________________________________________ _____
Memory utilization factor shall be computed as follows A Memory in use/allocated memory
B Memory in use/total memory connected C Memory allocated/total memory available D Memory committed/total memory available
Answer B
______________________________________________________________________________________ _____
File attributes are A Name
B Type C Location D All of these
Which structure prohibits the sharing of files and directories? A Tree structure
B One level structure C Two level structure D None of the these
Answer A
________________________________________________________________________________________ ___
Best method for allocation is
A Contiguous B Linked C Index D All of these Answer B ________________________________________________________________________________________ ___
Which one is best for memory allocation?
A First fit B Best fit C Worst fit D All of these Answer B ________________________________________________________________________________________ ___
The simplest directory structure is A Single level directory B Two level directory C Tree structure directory D None of these
Answer C
________________________________________________________________________________________ ___
A tree structured file directory system
A Allows easy storage and retrieval of file names B Is a much debated unnecessary feature
C Is not essential when we have millions of files D None of the above
Answer A
________________________________________________________________________________________ ___
The file structure that redefines its first record at a base of zero uses the term A Relative organization B Key fielding C Dynamic reallocation D Hashing Answer A ________________________________________________________________________________________ ___
Which of the following types of terminals is entirely dependent for all its capabilities on the computer system to which it is connected?
A Smart terminal B Dumb terminal C Micro computer D None of these Answer B ________________________________________________________________________________________ ___
File record length
A Should always be fixed B Should always be variable C Depends upon the size of the file
D Should be chosen to match the data characteristics Answer D
________________________________________________________________________________________ ___
FAT stands for
A File Accomodation Table B File Access Tape
C File Allocation Table D File Activity Table
Answer C
________________________________________________________________________________________ ___
________ is the time required by a sector to reach below read/write head.
A Seek Time
B Latency Time
C Access time
D None
Which of the following is the principal difference between a monochrome monitor and an RGB monitor? A Number of electron guns
B Resolution C Size D Cost Answer A __________________________________________________________________________________________ _
A file sometimes called a A Collection of input data B Data set
C Temporary place to store data
D Program
Answer B
__________________________________________________________________________________________ _
There are no cycles of
A General graph directory B Cyclic graph directory C One level directory D Two level directory
Answer B
__________________________________________________________________________________________ _
Solution of name collision problem is A Single level directory B Two level directory C Tree structure D All of these
Answer B
__________________________________________________________________________________________ _
When used with I\O devices the term intelligent implies A A color output capability
B Speech processing capability C High speed printing capability
D Features to support off line and online tasks Answer D
__________________________________________________________________________________________ _
Optical storage is a
A high-speed direct access storage device. B low-speed direct access storage device. C medium-speed direct access storage device. D high-speed sequential access storage device.
Answer C
__________________________________________________________________________________________ _
Memory protection is normally done by the A Processor and the associated hardware B Operating system C Compiler D User program Answer A __________________________________________________________________________________________ _
Program threats are
A Trojan horse B Trap door C Both A and B D None of these Answer C __________________________________________________________________________________________ _
Which of the following is the process by which a user’s access to physical data in the application is limited, based on his privileges ?
A Authorization B Authentication C Access Control D All of these Answer C __________________________________________________________________________________________ _
Worm was made up A One program B Two program C Three program D All of these
Trojan horse
A A code segment that misuses its file is called trojan horse B Good for file accessing
C Both A and B D None of these
Answer A
___________________________________________________________________________________________ A major security problem for operating system is
A Authentication problem B Physical problem C Human problem D None of these Answer A ___________________________________________________________________________________________ To protect system,there are how many security levels?
A One B Two C Three D Four Answer C ___________________________________________________________________________________________ Which of the following topologies consists of multiple CPUs connected by a single communication line running the length of the network?
A Tree B Ring C Star D Bus Answer D ___________________________________________________________________________________________ Which of the following is the process by which a user’s privileges ascertained ?
A Authorization B Authentication C Access Control D None of these Answer A ___________________________________________________________________________________________ An audit log
A Simply records the time
B User
C Type of all access to an object D All of these
Answer B
All of the following are examples of real security and privacy risks except A Hackers B Spam C Viruses D Identify theft Answer B ___________________________________________________________________________________________ Security violation due to
A Malicious B Accidental C Both A and B D None of these Answer C ___________________________________________________________________________________________ A public key encryption system
A Allows only the correct receiver to decode the data. B Allows only one to decode the transmission.
C Allows only the correct sender to decode the data. D Does not encode the data before transmitting it.
Answer A
___________________________________________________________________________________________ Which model estimates the total effort in terms of person,months of the technical project staff?
A Spiral
B Waterfall
C Prototyping
D COCOMO model
Answer D Lowest level of security is
A A B B C C D D Answer A ___________________________________________________________________________________________ Bootstrap or vector is called
A Grappling hook program
B Main program
C Secondary program D Primary storage
Answer B
In one time password
A The password is different in each instance B The password is same in each instance C Both A and B
D None of these Answer A
___________________________________________________________________________________________ The DIR command in DOS operating system
A Copies files B Erases files
C Extracts a list of file names D None of these
Answer C
___________________________________________________________________________________________ Malicious access are
A Unauthorized reading of data B Unauthorized modification of data C Unauthorized destruction of data D All of these
Answer D
___________________________________________________________________________________________ Audit log can be used to determine
A How and when the problem occurred B What amount of damage was done C When security has been violated D All of these
Answer C
___________________________________________________________________________________________ The most common approach to authenticating a user identity is
A User password B User log in C Hardware device D None of these Answer A ___________________________________________________________________________________________ In which model advantage of better testing in software development?
A Waterfall model B Prototyping C Iterative D All of these Answer C ___________________________________________________________________________________________
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