100 TOP Operating System Multiple Choice Questions and Answers

Read the most frequently asked 100 top Operating System multiple choice questions and answers PDF for freshers and experienced

Operating System Objective type Questions and Answers List


1 Translator for low level programming language were termed as
(A) Assembler
(B) Compiler
(C) Linker
(D) Loader
Ans: (A)

2 Analysis which determines the meaning of a statement once its grammatical structure becomes known is termed as
(A) Semantic analysis
(B) Syntax analysis
(C) Regular analysis
(D) General analysis
Ans: (A)

3 Load address for the first word of the program is called
(A) Linker address origin
(B) load address origin
(C) Phase library
(D) absolute library
Ans: (B)

4 Symbolic names can be associated with
A) Information
(B) data or instruction
(C) operand
(D) mnemonic operation
Ans: (B)

5 The translator which perform macro expansion is called a
(A) Macro processor
(B) Macro pre-processor
(C) Micro pre-processor
(D) assembler
Ans: (B)

6 Shell is the exclusive feature of
(A) UNIX
(B) DOS
(C) System software
(D) Application software
Ans: (A)

7 A program in execution is called
(A) Process
(B) Instruction
(C) Procedure
(D) Function
Ans: (A)

8 Interval between the time of submission and completion of the job is called
(A) Waiting time
(B) Turnaround time
(C) Throughput
(D) Response time
Ans: (B)

9 A scheduler which selects processes from secondary storage device is called
(A) Short term scheduler.
(B) Long term scheduler.
(C) Medium term scheduler.
(D) Process scheduler.
Ans: (C)

10 The scheduling in which CPU is allocated to the process with least CPU-burst time is called
(A) Priority Scheduling
(B) Shortest job first Scheduling
(C) Round Robin Scheduling
(D) Multilevel Queue Scheduling
Ans: (B)

11 The term ‘page traffic’ describes
(A) number of pages in memory at a given instant.
(B) number of papers required to be brought in at a given page request.
(C) the movement of pages in and out of memory.
(D) number of pages of executing programs loaded in memory.
Ans: (C)

12 The “turn-around” time of a user job is the
(A) time since its submission to the time its results become available.
(B) time duration for which the CPU is allotted to the job.
(C) total time taken to execute the job.
(D) time taken for the job to move from assembly phase to completion phase.

Ans: (C)
13 Which of the following can be used as a criterion for classification of data structures used in language processing.
(A) nature of a data structure
(B) purpose of a data structure
(C) lifetime of a data structure
(D) all of the above.

Ans: (D)
14 Memory utilization factor shall be computed as follows
(A) memory in use/allocated memory.
(B) memory in use/total memory connected.
(C) memory allocated/free existing memory.
(D) memory committed/total memory available.
Ans: (B)

15 Program ‘preemption’ is
(A) forced de allocation of the CPU from a program which is executing on the CPU.
(B) release of CPU by the program after completing its task.
(C) forced allotment of CPU by a program to itself.
(D) a program terminating itself due to detection of an error.
Ans: (A)

16 An assembler is
(A) programming language dependent.
(B) syntax dependant.
(C) machine dependant.
(D) data dependant.
Ans: (C)

17 Which of the following is not a fundamental process state
(A) ready
(B) terminated
(C) executing
(D) blocked
Ans: (D)

18 ‘LRU’ page replacement policy is
(A) Last Replaced Unit.
(B) Last Restored Unit.
(C) Least Recently Used.
(D) Least Required Unit.
Ans: (C)

19 Which of the following is true?
(A) Block cipher technique is an encryption technique.
(B) Steam cipher technique is an encryption technique.
(C) Both (A) and (B).
(D) Neither of (A) and (B).
Ans: (C)

20 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.
Ans: (D)

21 Program generation activity aims at
(A) Automatic generation of program
(B) Organize execution of a program written in PL
(C) Skips generation of program
(D) Speedens generation of program
Ans: (A)

22 Which amongst the following is not an advantage of Distributed systems?
(A) Reliability
(B) Incremental growth
(C) Resource sharing
(D) None of the above
Ans: (A)

23 An imperative statement
(A) Reserves areas of memory and associates names with them
(B) Indicates an action to be performed during execution of assembled program
(C) Indicates an action to be performed during optimization
(D) None of the above
Ans: (B)

24 Which of the following loader is executed when a system is first turned on or restarted
(A) Boot loader
(B) Compile and Go loader
(C) Bootstrap loader
(D) Relating loader
Ans: (C)

25 Poor response time is usually caused by
(A) Process busy
(B) High I/O rates
(C) High paging rates
(D) Any of the above
Ans: (D)

26 “Throughput” of a system is
(A) Number of programs processed by it per unit time
(B) Number of times the program is invoked by the system
(C) Number of requests made to a program by the system
(D) None of the above
Ans: (A)

27 The “blocking factor” of a file is
(A) The number of blocks accessible to a file
(B) The number of blocks allocated to a file
(C) The number of logical records in one physical record
(D) None of the above
Ans: (C)

28 Which of these is a component of a process precedence sequence?
(A) Process name
(B) Sequence operator ‘;’
(C) Concurrency operator ‘,’
(D) All of the above
Ans: (D)

29 Which amongst the following is valid syntax of the Fork and Join Primitive?
(A) Fork

30 Nested Macro calls are expanded using the
(A) FIFO rule (First in first out)
(B) LIFO (Last in First out)
(C) FILO rule (First in last out)
(D) None of the above
Ans: (B)

31 A parser which is a variant of top-down parsing without backtracking is
(A) Recursive Descend.
(B) Operator Precedence.
(C) LL(1) parser.
(D) LALR Parser.
Ans: (A)

32 The expansion of nested macro calls follows
(A) FIFO rule.
(B) LIFO rule.
(C) LILO rule.
(D) priority rule.
Ans: (B)

33. In a two-pass assembler, the task of the Pass II is to
(A) separate the symbol, mnemonic opcode and operand fields.
(B) build the symbol table.
(C) construct intermediate code.
(D) synthesize the target program.
Ans: (D)

34 A linker program
(A) places the program in the memory for the purpose of execution.
(B) relocates the program to execute from the specific memory area allocated to it.
(C) links the program with other programs needed for its execution.
(D) interfaces the program with the entities generating its input data.
Ans: (C)

35 Which scheduling policy is most suitable for a time-shared operating system
(A) Shortest-job First.
(B) Elevator.
(C) Round-Robin.
(D) First-Come-First-Serve.
Ans: (C)

36 A critical section is a program segment
(A) which should run in a certain specified amount of time.
(B) which avoids deadlocks.
(C) where shared resources are accessed.
(D) which must be enclosed by a pair of semaphore operations, P and V.
Ans: (C)

37 An operating system contains 3 user processes each requiring 2 units of resource R. The minimum number of units of R such that no deadlocks will ever arise is
(A) 4.
(B) 3.
(C) 5.
(D) 6.
Ans: (A)

38 Locality of reference implies that the page reference being made by a process
(A) will always be to the page used in the previous page reference.
(B) is likely to be the one of the pages used in the last few page references.
(C) will always be to one of the pages existing in memory.
(D) will always lead to a page fault.
Ans: (B)

39 Which of these is not a part of Synthesis phase
(A) Obtain machine code corresponding to the mnemonic from the Mnemonics table
(B) Obtain address of a memory operand from the symbol table
(C) Perform LC processing
(D) Synthesize a machine instruction or the machine form of a constant
Ans: (C)

40 The syntax of the assembler directive EQU is
(A) EQU

(B) EQU

(C) EQU
(D) None of the above
Ans: (B)

41 The following features are needed to implement top down parsing
(A) Source string marker
(B) Prediction making mechanism
(C) Matching and Backtracking mechanism
(D) All of the above
Ans: (D)

42 A macro definition consists of
(A) A macro prototype statement
(B) One or more model statements
(C) Macro pre-processor statements
(D) All of the above
Ans: (D)

43 The main reason to encrypt a file is to _________.
(A) Reduce its size
(B) Secure it for transmission
(C) Prepare it for backup
(D) Include it in the start-up sequence
Ans: (B)

44 Which of the following is not a key piece of information, stored in single page table entry, assuming pure paging and virtual memory
(A) Frame number
(B) A bit indicating whether the page is in physical memory or on the disk
(C) A reference for the disk block that stores the page
(D) None of the above
Ans: (C)

45 A UNIX device driver is
(A) Structured into two halves called top half and bottom half
(B) Three equal partitions
(C) Unstructured
(D) None of the above
Ans: (A)

46 The following is not a layer of IO management module
(A) PIOCS (Physical Input Output Control System)
(B) LIOCS (Logical Input Output Control System)
(C) FS (File System)
(D) MCS (Management Control System)
Ans: (D)

47 Which amongst the following is not a valid page replacement policy?
(A) LRU policy (Least Recently Used)
(B) FIFO policy (First in first out)
(C) RU policy (Recurrently used)
(D) Optimal page replacement policy
Ans: (C)

48 Consider a program with a linked origin of 5000. Let the memory area allocated to it have the start address of 70000. Which amongst the following will be the value to be loaded in relocation register?
(A) 20000
(B) 50000
(C) 70000
(D) 90000
Ans: (None of the above choice in correct. )

49 An assembly language is a
(A) low level programming language
(B) Middle level programming language
(C) High level programming language
(D) Internet based programming language
Ans: (A)

50 TII stands for
(A) Table of incomplete instructions
(B) table of information instructions
(C) translation of instructions information
(D) translation of information instruction
Ans: (A)

51 An analysis, which determines the syntactic structure of the source statement, is called
(A) Sementic analysis
(B) process analysis
(C) Syntax analysis
(D) function analysis
Ans: (C)

52 Action implementing instruction’s meaning are a actually carried out by
(A) Instruction fetch
(B) Instruction decode
(C) instruction execution
(D) Instruction program
Ans: (C)

53 The field that contains a segment index or an internal index is called
(A) target datum
(B) target offset
(C) segment field
(D) fix dat
Ans: (A)

54 A program in execution is called
(A) process
(B) function
(C) CPU
(D) Memory
Ans: (A)

55 Jobs which are admitted to the system for processing is called
(A) long-term scheduling
(B) short-term scheduling
(C) medium-term scheduling
(D) queuing
Ans: (A)

56 A set of techniques that allow to execute a program which is not entirely in memory is called
(A) demand paging
(B) virtual memory
(C) auxiliary memory
(D) secondary memory
Ans: (B)

57 SSTF stands for
(A) Shortest-Seek-time-first scheduling
(B) small – small-time-first
(C) simple-seek-time-first
(D) small-simple-time-first scheduling
Ans: (A)

58 Before proceeding with its execution, each process must acquire all the resources it needs is called
(A) hold and wait
(B) No pre-emption
(C) circular wait
(D) starvation
Ans: (A)

59 Virtual memory is
(A) simple to implement
(B) used in all major commercial operating systems
(C) less efficient in utilization of memory
(D) useful when fast I/O devices are not available
Ans: (B)

60 Relocation bits used by relocating loader are specified by
(A) Relocating loader itself
(B) Assembler or Translator
(C) Macro processor
(D) Both (A) and (B)
Ans: (B)

61 Resolution of externally defined symbols is performed by
(A) Linker
(B) Loader
(C) Compiler
(D) Editor
Ans: (A)

62 Relocatable programs
(A) cannot be used with fixed partitions
(B) can be loaded almost anywhere in memory
(C) do not need a linker
(D) can be loaded only at one specific location
Ans: (B)

63 Page stealing
(A) is a sign of efficient system
(B) is taking page frames other working sets
(C) should be the tuning goal
(D) is taking larger disk spaces for pages paged out
Ans: (B)

64 The total time to prepare a disk drive mechanism for a block of data to be read from is its
(A) latency
(B) latency plus transmission time
(C) latency plus seek time
(D) latency plus seek time plus transmission time
Ans: (C)

65 To avoid race condition, the maximum number of processes that may be simultaneously inside the critical section is
(A) zero
(B) one
(C) two
(D) more than two
Ans: (B)

66 The memory allocation scheme subject to “external” fragmentation is
(A) segmentation
(B) swapping
(C) pure demand paging
(D) multiple fixed contiguous partitions
Ans: (A)

67 Page fault frequency in an operating system is reduced when the
(A) processes tend to the I/O-bound
(B) size of pages is reduced
(C) processes tend to be CPU-bound
(D) locality of reference is applicable to the process
Ans: (D)

68 In which of the following page replacement policies Balady’s anomaly occurs?
(A) FIFO
(B) LRU
(C) LFU
(D) NRU
Ans: (A)

69 Which of the following are language processors?
(A) Assembler
(B) Compiler
(C) Interpreter
(D) All of the above
Ans: (D)

70 Virtual memory can be implemented with
(A) Segmentation
(B) Paging
(C) None
(D) all of the above
Ans: (D)

71. Round robin scheduling is essentially the preemptive version of ________.
A. FIFO
B. Shortest job first
C. Shortes remaining
D. Longest time first
Ans: A

72. A page fault occurs
A. when the page is not in the memory
B. when the page is in the memory
C. when the process enters the blocked state
D. when the process is in the ready state
Ans: A

73. Which of the following will determine your choice of systems software for your computer ?
A. Is the applications software you want to use compatible with it ?
B. Is it expensive ?
C. Is it compatible with your hardware ?
D. Both A. and C.
Ans: D

74. Let S and Q be two semaphores initialized to A., where P0 and PA. processes the following statements wait(S);wait(Q); —; signal(S);signal(Q) and wait(Q); wait(S);—;signal(Q);signal(S); respectively. The above situation depicts a _________ .
A. Semaphore
B. Deadlock
C. Signal
D. Interrupt
Ans: B

75. What is a shell ?
A. It is a hardware component
B. It is a command interpreter
C. It is a part in compiler
D. It is a tool in CPU scheduling
Ans: B

76. Routine is not loaded until it is called. All routines are kept on disk in a relocatable load format. The main program is loaded into memory & is executed. This type of loading is called _________
A. Static loading
B. Dynamic loading
C. Dynamic linking
D. Overlays
Ans: C

77. In the blocked state
A. the processes waiting for I/O are found
B. the process which is running is found
C. the processes waiting for the processor are found
D. none of the above
Ans: A

78. What is the memory from A.K – 6D.0K called ?
A. Extended Memory
B. Normal Memory
C. Low Memory
D. Conventional Memory
Ans: D

79. Virtual memory is __________.
A. An extremely large main memory
B. An extremely large secondary memory
C. An illusion of extremely large main memory
D. A type of memory used in super computers.
Ans: C

80. The process related to process control, file management, device management, information about system and communication that is requested by any higher level language can be performed by __________.
A. Editors
B. Compilers
C. System Call
D. Caching
Ans: C

81. Multiprogramming systems ________.
A. Are easier to develop than single programming systems
B. Execute each job faster
C. Execute more jobs in the same time
D. Are used only on large main frame computers
Ans: C

82. Which is not the state of the process ?
A. Blocked
B. Running
C. Ready
D. Privileged
Ans: D

83. The solution to Critical Section Problem is : Mutual Exclusion, Progress and Bounded Waiting.
A. The statement is false
B. The statement is true.
C. The statement is contradictory.
D. None of the above
Ans: B

84. The problem of thrashing is effected scientifically by ________.
A. Program structure
B. Program size
C. Primary storage size
D. None of the above
Ans: A

85. The state of a process after it encounters an I/O instruction is __________.
A. Ready
B. Blocked/Waiting
C. Idle
D. Running
Ans: B

86. The number of processes completed per unit time is known as __________.
A. Output
B. Throughput
C. Efficiency
D. Capacity
Ans: B

87. _________ is the situation in which a process is waiting on another process,which is also waiting on another process … which is waiting on the first process. None of the processes involved in this circular wait are making progress.
A. Deadlock
B. Starvation
C. Dormant
D. None of the above
Ans: A

88. Which of the following file name extension suggests that the file is Backup copy of another file ?
A. TXT
B. COM
C. BAS
D. BAK
Ans: D

89. Which technique was introduced because a single job could not keep both the CPU and the I/O devices busy?
A. Time-sharing
B. SPOOLing
C. Preemptive scheduling
D. Multiprogramming
Ans: D

90. A critical region
A. is a piece of code which only one process executes at a time
B. is a region prone to deadlock
C. is a piece of code which only a finite number of processes execute
D. is found only in Windows NT operation system
Ans: A

91. The mechanism that bring a page into memory only when it is needed is called ______.
A. Segmentation
B. Fragmentation
C. Demand Paging
D. Page Replacement
Ans: C

92. PCB =
A. Program Control Block
B. Process Control Block
C. Process Communication Block
D. None of the above
Ans: B

93. FIFO scheduling is ________.
A. Preemptive Scheduling
B. Non Preemptive Scheduling
C. Deadline Scheduling
D. Fair share scheduling
Ans: B

94. Switching the CPU to another Process requires to save state of the old process and loading new process state is called as __________.
A. Process Blocking
B. Context Switch
C. Time Sharing
D. None of the above
Ans: B

95. Which directory implementation is used in most Operating System?
A. Single level directory structure
B. Two level directory structure
C. Tree directory structure
D. Acyclic directory structure
Ans: C

96. ______ is a high level abstraction over Semaphore.
A. Shared memory
B. Message passing
C. Monitor
D. Mutual exclusion
Ans: C

97. A tree sturctured file directory system
A. allows easy storage and retrieval of file names
B. is a much debated unecessary feature
C. is not essential when we have millions of files
D. none of the above
Ans: A

98. Which of the following is not a fundamental process state
A. ready
B. terminated
C. executing
D. blocked
Ans: D

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