PRACTICE PAPER OPERATING SYSTEM PART-1

UGC NET JUNE 2013 SYLLABUS, MODEL PAPER/ PREVIOUS YEARS SOLVED QUESTION PAPERS.
UGC NET (NATIONAL ELIGIBILITY TEST) : OLD SOLVED/PREVIOUS EXAM QUESTION PAPERS WITH SOLUTIONS AND EXPLANATIONS AND FREE STUDY MATERIALS.
COMPUTER MEMORY BASED PREVIOUS YEARS SOLVED PAPERS I, II AND III TO PREPARE AND PASS THE UGC NET/SLET ENTRANCE EXAMINATION WITH HIGH PERCENTAGE.
COMPUTER BASIC QUESTIONS FOR BANK EXAM, HTAT, CTAT, TAT, UGC-NET, INTERVIEW AND OTHER EXAM'S, WHERE BASIC QUESTION'S ARE REQUIRED.

1) Round Robin algorithm is essentially the preemptive version of ?

1.  FIFO
2. Shortest Job First
3. Shortest Remaining
4. Longest time first

Answer = a
Explanation: In round robin algorithm time slices are assigned to the processes in equal portion and in circular order.

2) A page fault occurs ?

1. when the page is not in the memory
2. when the page is in the memory
3. when the process enters the blocked state
4. when the process is in the ready state

Answer = a
Explanation: A page fault occurs when a process accesses a page that has been mapped into the address space, but is not loaded into the physical memory.

3) Which of the following will determine your choice of systems software for your computer?

1. Is the applications software you want to use compatible with it ?
2. Is it expensive ?
3. Is it compatible with your hardware ?
4. Both 1 and 3

Answer = D
Explanation: The choice of the software should be compatible with the hardware and should not be expensive enough.

4) What is a shell ? ?

1. It is a hardware component
2. It is a command interpreter
3. It is a part in compiler
4. It is a tool in CPU scheduling.

Answer = B
Explanation: A Shell is the command line interpreter that provides the traditional user interface for the UNIX operating system. Users direct the operation of the computer by entering commands as text for a command line interpreter to execute or by creating text scripts of one or more such commands.

5) 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... ?

1. Static loading
2. Dynamic loading
3. Dynamic linking
4. Overlays

Answer = C
Explanation: Dynamic linking provides the facility to load or unload routines at runtime

6) In the blocked state ?

1. the processes waiting for I/O are found
2. the process which is running is found
3. the processes waiting for the processor are found
4. none of the above

Answer = A
Explanation: All the processes that are waiting for the completion of some event such as I/O operation or a signal are in Blocked state.

7) What is the memory from 1K - 640K called ?

1. Extended Memory
2. Normal Memory
3. Low Memory
4. Conventional Memory

Answer = D

8) Virtual memory is ..... ?

1. An extremely large main memory
2. An extremely large secondary memory
3. An illusion of extremely large main memory
4. A type of memory used in super computers.

Answer = C
Explanation: Virtual memory allows a program to be designed as though there is only one kind of memory, "virtual" memory, which behaves like directly addressable read/write memory (RAM).

9) Which is not the state of the process ?

1. Blocked
2. Running
3. Ready
4. Privileged

ANS D.

10) The number of processes completed per unit time is known as.... ?

1. Output
2. Throughput
3. Efficiency
4. Capacity

Answer = B
Explanation: Throughput is the amount of data transfer from one place to another. It is measured in Kbps, Gbps, Mbps

11) Which of the following file name extension suggests that the file is Backup copy of another file ?

1. TXT
2. COM
3. BAS
4. BAK

Answer = D
Explanation: BAK extension is used for the backup files however the extension should be removed before opening the file to open it correctly. Eg : "myfile.doc.bak"should be renamed with "myfile.doc".

12) FIFO scheduling is.....

1. Preemptive Scheduling
2. Non Preemptive Scheduling
3. Deadline Scheduling
4. Fair share scheduling

Answer = B
Explanation: In the non preemptive scheduling the CPU can not take back from the process to which it is assigned, until it completes its execution.

13)Switching the CPU to another Process requires to save state of the old process and loading new process state is called as ...

1. Process Blocking
2. Context Switch
3. Time Sharing
4. None of the above

Answer = B
Explanation: The old state of the process can be saved through the concept of context switching.

14)The Banker's algorithm is used

1. to prevent deadlock in operating systems
2. to detect deadlock in operating systems
3. to rectify a deadlocked state
4. none of the above

Answer = A
Explanation: In an operating system, a deadlock is a situation which occurs when a process enters a waiting state because a resource requested by it is being held by another waiting process, which in turn is waiting for another resource. If a process is unable to change its state indefinitely because the resources requested by it are being used by other waiting process, then the system is said to be in a deadlock.

15)A thread

1. is a lightweight process where the context switching is low
2. is a lightweight process where the context switching is high
3. is used to speed up paging
4. none of the above

Answer = A

16) A tree structured file directory system

1. allows easy storage and retrieval of file names
2. is a much debated unnecessary feature
3. is not essential when we have millions of files
4. none of the above

Answer = A
Explanation: It is easy to access anything if it is in hierarchical structure.

17) Full Form Of PCB

1. Program Control Block
2. Process Control Block
3. Process Communication Block
4. None of the above

Answer = B
Explanation: It is also called the Task Controlling Block or Task Struct that contains the information needed to manage a particular process.

18)The mechanism that bring a page into memory only when it is needed is called....?

1. Segmentation
2. Fragmentation
3. Demand Paging
4. Page Replacement

Answer = C
Explanation: Under the concept of demand paging , the page is brought into the memory only when it is needed.

19) Which technique was introduced because a single job could not keep both the CPU and the I/O devices busy?

1. Time-sharing
2. Spooling
3. Preemptive scheduling
4. Multiprogramming

Answer = D
Explanation: Through Multiprogramming multiple processes gets executed at a same time.

20) Which directory implementation is used in most Operating System ?Single level directory structure

1. Two level directory structure
2. Tree directory structure
3. Acyclic directory structure
4. Hash tree structure

Answer = C

21)Virtual memory is ?

1. Extremely large main memory
2. Extremely large secondary memory
3. An illusion of an extremely large memory
4. A type of memory used in super computers

Answer = C
Explanation: Virtual memory is a feature of Operating System that enables a process to use a memory independent of other processes.

22) Spatial locality refers to the problem that once a location is referenced ?

1. It will not be referenced again
2. It will be referenced again
3. A nearby location will be referenced soon
4. None of Above

Answer = B
Explanation: Spatial locality or locality of reference stats that the same value or related value is going to be referenced again.

23) Which of the following is an example of SPOOLED device?

1. The terminal used to enter the input data for a program being executed
2. The secondary memory device in a virtual memory system
3. A line printer used to print the output of number of job's
4. None of above

Answer = C
Explanation:Line printer used to print the output of number of job's is an example of print spooling. In print spooling documents are loaded into the buffer and then the printer pulls then off the buffer at its own rate.

24) Page fault occurs when ?

1. The page in corrupted by application software
2. The page is in main memory
3. The page is not in main memory
4. One tries to divide number by 0

Answer = C
Explanation:Page fault occurs when the page that is not in the main memory is tried to be accessed.

5) Overlays is ?

1. A part of Operating System
2. A specific memory location
3. A single contiguous memory that was used in the olden days for running large programs by swapping
4. Overloading the system with many user files

Answer = C
Explanation: An overlay is when a process replaces itself with the code of another program.

26) Determine the number of page faults when references to pages occurs in the order 1,2,4,5,2,1,2,4. Assume that the main memory can accommodate 3 pages and the main memory already has the pages 1 and 2. With page 1 having been brought earlier that page 2(Assume LRU algorithm is used) ?

1. 3
2. 5
3. 4
4. None

Answer = C
Explanation:As the reference string is 1,2,4,5,2,1,2,4 so if LRU page replacement algorithm is used then there will be 4 page faults.

27) Concurrent processed are processed that ?

1. Do not overlap in time
2. Overlap in time
3. Are executed by processor at the same time
4. None of Above

Answer = B
Explanation:Concurrent means something that executed at the same time ad something else.

28) The rage replacement policy that sometimes leads to more page faults when the size of the memory is increased is ?

1. FIFO
2. LRU
3. no such policy exists
4. None of Above

Answer = A
Explanation:If the size of memory is increased and FIFO page replacement algorithm is used then there will be more page faults.

29) The only transition that is initiated by the user process itself is ?

1. block
2. dispatch
3. wake up
4. None of Above

Answer = A

30) Working set(r,k) at an instance of time t, is a set of ?

1. k future references that operating system will make
2. Future references that the operating system will make in the next 'k' time units
3. k references with high frequency
4. Pages that have been referenced in the last k time units

Answer = D

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