Advance Operating System Quiz

1. Which of the following is the reason that the least recently used (LRU) algorithm is usually not used as a page replacement algorithm?

A. Other practical schemes such as MIN do a better job.

B. LRU requires knowledge of the future to work correctly.

C. LRU is too inefficient to implement in practice.

D. The Clock algorithm always outperforms LRU.

 

2. Which of the following are shared between threads in the same process?

A. registers

B. page table

C. stack

D. stack pointer

E. None of these are shared

 

3. The IP service model guarantees which of the following?

A. The contents of a packet will not be corrupted

B. That at least one copy of a packet will arrive at the destination

C. That no more than one copy of a packet will arrive at the destination

D. That packets sent in order will be delivered in order

E. None of the above

 

4. Using the SCAN (a.k.a. elevator) disk scheduling algorithm, determine how far the disk head moves servicing the following outstanding requests: 150, 19, 20, 900, 99. Assume the disk's head is currently over track 100 and moving toward smaller track numbers.  Also, assume that all of these track requests have already been received.

A. 962 tracks

B. 1064 tracks

C. 1681 tracks

D. 1863 tracks

E. None of these are true

 

5. If a process has allocated every 1024th virtual page (e.g. it has allocated virtual pages 0, 1024, 2048, 3072, 4096, 5120 ... 1024000), which one of the following page table schemes will use the LEAST amount of memory?

A. A flat page table

B. A two-level page table with 1024 first level entries

C. A two-level page table with 2048 first level entries

D. An inverted page table

E. Each of the above page table will use exactly the same amount of memory

6. Making no assumptions about the processes being scheduled, which of these scheduling algorithms will prevent starvation?

I. First Come First Served  (doesn’t work if a job runs forever—infinite loop)

II. Round Robin

III. Priority

 

A. I

B. II

C. I & III

D. I, II, & III

 

7. Consider a group of RAID4 disks. This group has four data disks and one parity disk. Which of the following are true?

I. Any data disk but NOT the parity disk can be reconstructed from the other four

II. The parity disk must be read whenever one of the data disks is read

III. The parity disk must be written whenever one of the data disks is written

 

A. III

B. I & III

C. II & III

D. I, II, & III

E. None of the above

 

8. Which of the following is true about two threads running in the same process?

A. One thread can both read and write another thread's registers

B. One thread can change the other thread's program counter

C. One thread can neither read nor write the other thread's stack

D. One thread can both read and write the other thread's stack (there is no address space protection between threads in the same process)

 

9.Which disk block allocation scheme will require the most I/O operations for random access to a large file?

A. Indexed allocation

B. Linked allocation

C. Contiguous allocation

D. I-node allocation

E. Each scheme requires approximately the same number of I/O operations

 

10. Which of the following does NOT solve deadlock?

A. Acquiring all resources before using any of them   (this is not acquiring all resources or no resources.  This doesn’t eliminate hold and wait)

B. Only acquiring resources in order based on a predetermined priority

C. Acquiring a maximum of one resource at a time (can’t have hold and wait if only have one resource)

D. If a resource is unavailable, releasing all resources and waiting for all required resources to become available

11. What is the primary reason that a translation lookaside buffer (TLB) is used?

A. A TLB ensures that a process does not access memory outside of its address space

B. A TLB makes translating virtual addresses to physical addresses faster

C. A TLB allows multiple processes to share the L1 cache

D. A TLB makes translating virtual addresses to physical addresses possible

E. None of the above

 

12. Which of the following is not a solution to thrashing?

A. Running fewer processes

B. Increasing the speed of the CPU

C. Increasing the size of physical memory

D. Rewriting programs to have better locality

E. These all solve the problem of thrashing

 

13. Which of the following is NOT a way to make file systems faster?

A. Put parts of a file on many different tracks so part of it can be accessed no matter where the disk head is

B. Cache frequently used blocks in memory so they can be accessed at memory speeds instead of disk speeds

C. Use a disk scheduling algorithm to minimize the distance between seeks

D. Put frequently used files or directories near the center of the disk so on average they won't be far from the read head

E. All of these will make a file system faster

 

14. Which of the following is true about base and bounds registers?

I. They offer protection between processes

II. They lead to internal fragmentation of physical memory

III. Once a process has been started at a given memory location, it cannot be moved to another location

 

A. I

B. II

C. I & II

D. I, II, & III

E. None of the above

 

15. Which of the following can I do without knowing your private key?

A. Pretend to send a private message on your behalf

B. Decrypt messages that were intended for only you

C. Send you a message that only you can read

D. Digitally sign a message on your behalf

E.  I must know your private key to perform all of these operations

 

16. Public/private key encryption is usually avoided because

A. It is much slower than symmetric key encryption

B. It is only useful when encrypting large amounts of data

C. It is not as secure as symmetric key encryption

D. It cannot be used unless two parties can exchange their private keys securely

E. None of the above

Suppose a system has only three physical pages. Given the following sequence of virtual page references, determine the number of page faults that are required. Initially, assume that the physical pages are not being used by any virtual page.

1 2 1 1 3 2 1 4 3 1 1 2 4 1 5 6 2 1

17. Using the first in first out (FIFO) replacement policy

A. 9

B. 10

C. 11

D. 12

E.  None of the above

 

18. Using the least recently used (LRU) replacement policy

A. 9

B. 10

C. 11

D. 12

E.  None of the above

 

 

19. Which of the following is NOT a use of TCP sequence numbers?

A. To ensure that data is delivered to the application in the order it was sent

B. To distinguish duplicate packets

C. To determine how much data is left to send

D. All of these are uses

 

20. Which of the following is NOT a property of Ethernet?

A. Nodes retransmit packets if there was a collision

B. Sending packets that are too big does NOT affect collision detection

C. Nodes retransmit packets if an acknowledgement is not received

D. After a collision, both nodes wait a random amount of time before retransmitting a packet

E. These are all properties of Ethernet

Algorithm Quiz

1. Two main measures for the efficiency of an algorithm are 

A. Processor and memory

B. Complexity and capacity

C. Time and space

D. Data and space

2. The time factor when determining the efficiency of algorithm is measured by

A. Counting microseconds 

B. Counting the number of key operations

C. Counting the number of statements

D. Counting the kilobytes of algorithm

3. The space factor when determining the efficiency of algorithm is measured by

A. Counting the maximum memory needed by the algorithm

B. Counting the minimum memory needed by the algorithm

C. Counting the average memory needed by the algorithm

D. Counting the maximum disk space needed by the algorithm

4. Which of the following case does not exist in complexity theory

A. Best case

B. Worst case

C. Average case

D. Null case

5. The Worst case occur in linear search algorithm when 

A. Item is somewhere in the middle of the array

B. Item is not in the array at all

C. Item is the last element in the array

D. Item is the last element in the array or is not there at all

6. The Average case occur in linear search algorithm

A. When Item is somewhere in the middle of the array 

B. When Item is not in the array at all

C. When Item is the last element in the array

D. When Item is the last element in the array or is not there at all

7. The complexity of the average case of an algorithm is 

A. Much more complicated to analyze than that of worst case

B. Much more simpler to analyze than that of worst case

C. Sometimes more complicated and some other times simpler than that of worst case 

D. None or above

8. The complexity of linear search algorithm is

A. O(n)

B. O(log n)

C. O(n^2)

D. O(n log n)

9. The complexity of Binary search algorithm is 

A. O(n)

B. O(logn)

C. O(n^2)

D. O(n log n)

10. The complexity of Bubble sort algorithm is 

A. O(n)

B. O(log n)

C. O(n^2)

D. O(n log n)

11. The complexity of merge sort algorithm is

A. O(n)

B. O(log n)

C. O(n^2)

D. O(n log n)

12. The indirect change of the values of a variable in one module by another module is called

A. internal change

B. inter-module change

C. side effect

D. side-module update

13. Which of the following data structure is not linear data structure?

A. Arrays

B. Linked lists

C. Both of above

D. None of above

14. Which of the following data structure is linear data structure?

A. Trees

B. Graphs

C. Arrays

D. None of above

15. The operation of processing each element in the list is known as

A. Sorting

B. Merging

C. Inserting

D. Traversal

16. Finding the location of the element with a given value is:

A. Traversal

B. Search

C. Sort

D. None of above

17. Arrays are best data structures

A. for relatively permanent collections of data

B. for the size of the structure and the data in the structure are constantly changing

C. for both of above situation

D. for none of above situation

18. Linked lists are best suited

A. for relatively permanent collections of data 

B. for the size of the structure and the data in the structure are constantly changing

C. for both of above situation

D. for none of above situation

19. Each array declaration need not give, implicitly or explicitly, the information about

A. the name of array

B. the data type of array

C. the first data from the set to be stored

D. the index set of the array

20. The elements of an array are stored successively in memory cells because

A. by this way computer can keep track only the address of the first element and the addresses of other elements can be calculated

B. the architecture of computer memory does not allow arrays to store other than serially

C. both of above

D. none of above

21. What do you mean by Amortized Analysis?

Amortized analysis finds the average running time per operation over a worst case

sequence of operations. Amortized analysis differs from average-case performance in that

probability is not involved; amortized analysis guarantees the time per operation over

worst-case performance.

22. What are important problem types? (or) Enumerate some important types of

problems.

1. Sorting 2. Searching

3. Numerical problems 4. Geometric problems

5. Combinatorial Problems 6. Graph Problems

7. String processing Problems

23. Name some basic Efficiency classes

1. Constant 2. Logarithmic 3. Linear 4. nlogn

5. Quadratic 6. Cubic 7. Exponential 8. Factorial

24. What are algorithm design techniques?

Algorithm design techniques ( or strategies or paradigms) are general approaches to solving problems algorithmatically, applicable to a variety of problems from different areas of computing. General design techniques are:

(i) Brute force (ii) divide and conquer

(iii) decrease and conquer (iv) transform and concquer

(v) greedy technique (vi) dynamic programming

(vii) backtracking (viii) branch and bound

25. How is an algorithm’s time efficiency measured?

Time efficiency indicates how fast the algorithm runs. An algorithm’s time

efficiency is measured as a function of its input size by counting the number of times its basic operation (running time) is executeD. Basic operation is the most time consuming operation in the algorithm’s innermost loop.

26. What is Big ‘Oh’ notation?

A function t(n) is said to be in O(g(n)), denoted t(n) O(g(n)) , if t(n) is bounded aboveby some constant multiple of g(n) for all large n, i.e., if there exist some positive constantc and some nonnegative integers n0 such that

t(n) ≤ cg(n) for all n≥ n0

27. What is an Activation frame?

It is a storage area for an invocation of recursive program (parameters, local

variables, return address/value etC.). Activation frame allocated from frame stack pointed by frame pointer.

28. Define order of an algorithm

Measuring the performance of an algorithm in relation with the input size n is known as order of growth.

29. What is recursive call?

Recursive algorithm makes more than a single call to itself is known as recursive call. An algorithm that calls itself is direct recursive.An algorithm”A” is said to be indirect recursive if it calls another algorithm which in turn calls “A”.

30. What do you mean by stepwise refinement?

In top down design methodology the problem is solved in sequence (step by step)is known as stepwise refinement.

31. How is the efficiency of the algorithm defined?

The efficiency of an algorithm is defined with the components.

(i) Time efficiency -indicates how fast the algorithm runs

(ii) Space efficiency -indicates how much extra memory the algorithm needs

32. Define direct recursive and indirect recursive algorithms.

Recursion occurs where the definition of an entity refers to the entity itself.

Recursion can be direct when an entity refers to itself directly or indirect when it refers to other entities which refers to it. A (Directly) recursive routine calls itself. Mutually recursive routines are an example of indirect recursion. A (Directly) recursive data type

contains pointers to instances of the data type.

33. Which data structure allows deleting data elements from front and inserting at rear?

A. Stacks 

B. Queues 

C. Deques 

D. Binary search tree

34.    Identify the data structure which allows deletions at both ends of the list but insertion at only one end.

A. Input-restricted deque

B. Output-restricted deque

C. Priority queues

D. None of above

35.    Which of the following data structure is non-linear type?

A. Strings

B. Lists

C. Stacks

D. None of above

36.    Which of the following data structure is linear type?

A. Strings

B. Lists

C. Queues

D. All of above

37.    To represent hierarchical relationship between elements, which data structure is suitable?

A. Deque

B. Priority

C. Tree

D. All of above

38.    A binary tree whose every node has either zero or two children is called

A. Complete binary tree

B. Binary search tree

C. Extended binary tree

D. None of above

39.    The depth of a complete binary tree is given by

A. Dn = n log2n

B. Dn = n log2n+1

C. Dn = log2n

D. Dn = log2n+1

40.    When representing any algebraic expression E which uses only binary operations in a 2-tree,

A. the variable in E will appear as external nodes and operations in internal nodes

B. the operations in E will appear as external nodes and variables in internal nodes

C. the variables and operations in E will appear only in internal nodes

D. the variables and operations in E will appear only in external nodes

41.    A binary tree can easily be converted into q 2-tree

A. by replacing each empty sub tree by a new internal node

B. by inserting an internal nodes for non-empty node

C. by inserting an external nodes for non-empty node

D. by replacing each empty sub tree by a new external node

42.  When converting binary tree into extended binary tree, all the original nodes in binary tree are

A. internal nodes on extended tree

B. external nodes on extended tree

C. vanished on extended tree

D. None of above

43. The post order traversal of a binary tree is DEBFCA. Find out the pre order traversal

A. ABFCDE

B. ADBFEC

C. ABDECF

D. ABDCEF

44.  Which of the following sorting algorithm is of divide-and-conquer type?

A. Bubble sort

B. Insertion sort

C. Quick sort

D. All of above

45.  An algorithm that calls itself directly or indirectly is known as

A. Sub algorithm

B. Recursion

C. Polish notation

D. Traversal algorithm

46.  In a binary tree, certain null entries are replaced by special pointers which point to nodes higher in the tree for efficiency. These special pointers are called

A. Leaf

B. branch

C. path

D. thread

47.  The in order traversal of tree will yield a sorted listing of elements of tree in

A. Binary trees

B. Binary search trees

C. Heaps

D. None of above

48.  In a Heap tree

A. Values in a node is greater than every value in left sub tree and smaller than right sub tree

B. Values in a node is greater than every value in children of it

C. Both of above conditions applies

D. None of above conditions applies

49.  In a graph if e=[u, v], Then u and v are called

A. endpoints of e

B. adjacent nodes

C. neighbors

D. all of above

50.  A connected graph T without any cycles is called

A. a tree graph

B. free tree

C. a tree

D. All of above

51.  In a graph if e=(u, v) means

A. u is adjacent to v but v is not adjacent to u

B. e begins at u and ends at v

C. u is processor and v is successor

D. both b and c

52. If every node u in G is adjacent to every other node v in G, A graph is said to be

A. isolated

B. complete

C. finite

D. strongly connected