Distributed Computing - Quiz 3 - BITS WILP - Mtec Software Systems - 2017

Distributed Computing - Quiz 3

BITS WILP - Mtec Software Systems - 2017 

1. Which of the following is not a part of Job Management System of a cluster?
Select one:
job scheduler
user server
resource manager
recovery manager

Ans: recovery manager

2. Which of the following is not a semantic index?
Select one:
database key
document name
index given by a hash mechanism
keyword

Ans: index given by a hash mechanism

3. In the Byzantine agreement problem
Select one:
there can be more than one source process
there is no source process
only one process is the source process
all processes are source processes


Ans: only one process is the source process

4. Which of the following is not a feature of P2P networks?
Select one:
self replicating
distributed control
self organizing
anonymity

Ans: self replicating

5. If the total number of faulty processes present in a synchronous system is k, then the recursive formulation of the Byzantine agreement

tree algorithm runs for
Select one:
k + 2 rounds
k + 1 rounds
k rounds
2k rounds

Ans: k + 1 rounds

6. For a Chord ring having n nodes, the local space requirement at each node is
Select one:
O(n2)
O(log n)
O(n)
O(1)

Ans: O(log n)

7. The Byzantine agreement tree algorithm is initiated by
Select one:
a single lieutenant
all commanders
a single commander
all lieutenants

Ans: a single commander

8. In scalable lookup for Chord, the routing table of each node is termed as
Select one:
finger table
search table
lookup table
hash table

Ans: finger table

9. For a list L, the operation head(L) gives
Select one:
the first member of list L
the list L after deleting the last member of L
the list L after deleting the first member of L
the last member of list L

Ans: the first member of list L

10. In context of cluster computing, SSI stands for
Select one:
Single System Image
System Service Interdependence
Synchronous System Infrastructure
Secure System Interaction

Ans: Single System Image

11. In the iterative formulation of the Byzantine agreement tree algorithm for n processes,  each node at level h - 1 of the tree data

structure at a non-initiator has
Select one:
n child nodes
n + h - 1 child nodes
n - h child nodes
n - (h + 1) child nodes

Ans: n - (h + 1) child nodes

12. In the Byzantine agreement problem
Select one:
50% of the processes must agree on a value
50% of the non-faulty processes must agree on a value
all processes must agree on a value
all non-faulty processes must agree on a value

Ans: all non-faulty processes must agree on a value

13. Authenticated messages help
Select one:
in detection of message loss
in detection of forgery
in detection of process failure
in detection of channel failure
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Ans: in detection of forgery

14. The agreement variable in any agreement algorithm
Select one:
should be multivalued
should be boolean
should be an integer
may be boolean or multivalued

Ans: may be boolean or multivalued

15. Gnutella uses
Select one:
remote indexing
distributed indexing
local indexing
centralized indexing


Ans: local indexing

16. Which type of failure occurs temporarily?
Select one:
permanent failure
transient failure
total failure
unplanned failure

Ans: transient failure

17. In the interactive consistency problem
Select one:
all faulty processes must agree on an array of values
all non-faulty processes must agree on an array of values
all non-faulty processes must agree on a single value
all faulty processes must agree on a single value

Ans: all faulty processes must agree on an array of values

18. Unstructured overlays use
Select one:
centralized indexing
distributed indexing
local indexing
random indexing

Ans: local indexing

19. In a P2P network, the rapid joining and departure of nodes is termed as
Select one:
power law property
churn
scale free property
small world phenomemon

Ans: churn

20. Availability is calculated as
Select one:
MTTF / MTTR
MTTR / (MTTF + MTTR)
MTTF / (MTTF + MTTR)
MTTR / MTTF

Ans: MTTF / (MTTF + MTTR)

21. Expanding ring strategy is a refinement of
Select one:
random walk
flooding
guided search
blind search

Ans: flooding

22. The total number of message types used by Gnutella is
Select one:
5
3
4
6

Ans: 4

23. In the recursive formulation of the Byzantine agreement tree algorithm, the number of parameters present in each oral message is
Select one:
3
5
4
2

Ans: 4

24. In a synchronous system, if there are 19 processes, then the Byzantine agreement problem is solvable if there are
Select one:
at most 6 faulty processes
8 faulty processes
at least 6 faulty processes
7 faulty processes

Ans: at most 6 faulty processes

25. In the consensus problem
Select one:
each process has an initial value
only one process has an initial value
at most 50% of the processes have initial values
at most two processes have initial values

Ans: each process has an initial value

Distributed Computing Quiz 2 - BITS WILP - Mtec Software Systems - 2017

Distributed Computing - Quiz 2

BITS WILP - Mtec Software Systems - 2017 

1. The number of messages exchanged by the Chandy–Misra–Haas algorithm for the AND model in order to detect a deadlock in a distributed system consisting of n sites and m processes is

Select one:
mn
(m(n−1))/2
(n(m−1))/2
(mn)/2

Ans: (m(n−1))/2

2. The ASSIGN_PRIVILEGE routine is executed by

Select one:
Raymond’s Tree-Based Algorithm
Chandy-Misra-Haas algorithm
Maekawa's algorithm
Lamport's algorithm

Ans: Raymond’s Tree-Based Algorithm

3. Which of the following is not an approach for implementing mutual exclusion in distributed systems?

Select one:
quorum-based approach
token-based approach
non-token-based approach
causal-ordering based approach

Ans: causal-ordering based approach

4. For a spanning tree having n nodes, a broadcast procedure requires

Select one:
2n messages
n2 messages
(n -  1) messages
n messages

Ans: (n -  1) messages

5. Which of the following local variables is not used in Synchronous Single-Initiator Spanning Tree algorithm using flooding?

Select one:
child
depth
parent
visited

Ans: child

6. For the single-resource model, maximum out-degree of a node in a WFG can be

Select one:
exactly 2
more than 1
any positive number
at most 1

Ans: at most 1

7. The termination criterion for the Asynchronous Single-Initiator Spanning Tree Algorithm using flooding is

Select one:
(Children ∪ Unrelated) = (Neighbors \ {parent})
Children = Neighbors
(Neighbors ∪ Unrelated) = Children
(Children ∪ Unrelated) = Neighbors

Ans: (Children ∪ Unrelated) = (Neighbors \ {parent})

8. In Lamport's algorithm for implementing distributed mutual exclusion, a site that wants to enter the critical section sends REQUEST messages to

Select one:
a subset of all the sites
all the other sites
only a single specific site
a predesignated leader site

Ans: all the other sites

9. The type of communication used in the Birman-Schiper-Stephenson protocol is

Select one:
convergecast
unicast
multicast
broadcast

Ans: broadcast

10. For a distributed system consisting of k processes, Raynal–Schiper–Toueg algorithm uses SENT arrays each of size

Select one:
k2
2k
k
k x k

Ans: k x k

11. In a distributed system, when a process sends a message to a subset of the processes then the type of communication is called

Select one:
multicasting
convergecasting
unicasting
broadcasting

Ans: multicasting

12. For a distributed system having K sites, the number of messages required by Lamport's algorithm for implementing distributed mutual exclusion per critical section invocation is

Select one:
K - 1
K
2(K - 1)
3(K - 1)

Ans: 3(K - 1)

13. The Chandy–Misra–Haas algorithm for the OR model uses

Select one:
request and response messages
probe messages
inquire messages
query and reply messages

Ans: query and reply messages

14. The synchronization delay for the Ricart–Agrawala algorithm is equal to

Select one:
twice the average message delay
thrice the average message delay
the average message delay
half of the average message delay

Ans: the average message delay

15. Liveness property with regard to causal ordering of messages states that

Select one:
a message that a process decides to send must eventually be sent
a message that arrives at a process must eventually be delivered to the process
a message that is in transit must eventually reach the destination process
a message that is lost during transmission must eventually be retransmitted

Ans: a message that arrives at a process must eventually be delivered to the process

16. For the Asynchronous Single-Initiator Spanning Tree Algorithm using flooding, ACCEPT messages are sent along

Select one:
the back edges
the cross edges
the tree edges
all edges

Ans: the tree edges

17. How many types of messages are used by the Asynchronous Single-Initiator Spanning Tree algorithm using flooding?

Select one:
2
3
5
4

Ans: 3

18. In a distributed system consisting of x processes, the space requirement at each process for the Raynal–Schiper–Toueg algorithm is

Select one:
O(x2) integers
O(x3) integers
O(x) integers
O(x4) integers

Ans: O(x2) integers

19. The system throughput for a distributed mutual exclusion algorithm is defined as

Select one:
the rate at which the system executes requests for the critical section
the rate at which the system sends messages to enable a process to enter the critical section
the rate at which the system receives requests for the critical section
the rate at which a process in the system sends requests for entering the critical section

Ans: the rate at which the system executes requests for the critical section

20. The safety property in context of distributed mutual exclusion algorithms states that

Select one:
at any instant, atmost a certain number of processes can execute the critical section
at any instant, atmost 2 processes can execute the critical section
at any instant, some process should be executing the critical section
at any instant, only one process can execute the critical section

Ans: at any instant, only one process can execute the critical section

21. For handling deadlocks, Maekawa’s algorithm uses the following types of messages

Select one:
REQUEST, FAILED, INQUIRE
REQUEST, REPLY, INQUIRE
FAILED, INQUIRE, YIELD
REQUEST, INQUIRE, YIELD

Ans: FAILED, INQUIRE, YIELD

22. The local space complexity at a node for the Synchronous Single-Initiator Spanning Tree algorithm using flooding is of the order of

Select one:
the degree of edge incidence
the sum of the diameter and the degree of edge incidence
the number of edges of the graph
the product of the number of edges and the number of nodes of the graph

Ans: the degree of edge incidence

23. For which of the algorithms for implementing distributed mutual exclusion, each process maintains a request-deferred array?

Select one:
Maekawa’s algorithm
Lamport's algorithm
Ricart–Agrawala algorithm
Suzuki–Kasami’s broadcast algorithm

Ans: Ricart–Agrawala algorithm

24. The number of rounds that are executed in the Synchronous Single-Initiator Spanning Tree algorithm using flooding is equal to

Select one:
the number of edges in the graph
the length of the longest path in the graph
the diameter of the graph
the number of nodes in the graph

Ans: the diameter of the graph

25. Which of the following type of multicast algorithm uses a token?

Select one:
communication history-based algorithm
moving sequencer algorithm
fixed sequencer algorithm
destination agreement algorithm

Ans: moving sequencer algorithm

Distributed Computing Quiz 1 BITS WILP - Mtec Software Systems - 2017

Distributed Computing Quiz 1

BITS WILP - Mtec Software Systems - 2017 

1. Consider the following statements:

(i) Middleware provides interoperability among distributed objects.

(ii) Middleware is independent of hardware platforms.

(iii) Middleware is dependent on operating systems.

Which of the following is true?

Select one:
a. (i) only
b. (iii) only
c. (i), (ii) and (iii)
d. (i) and (ii)

Ans: (i) and (ii)

2. The master variable used in the Spezialetti–Kearns algorithm denotes the

Select one:
a. identifier of the process that initiated the algorithm
b. identifier of the process that has received a marker
c. identifier of a process that has already recorded its snapshot
d. identifier of the process that has received a marker along each of its incoming channels

Ans: identifier of the process that initiated the algorithm

3. The number of stages in a 64-input and 64-output Omega network is

Select one:
4
8
6
16

Ans: 6

4. Which of the following statement is false in context of Lai-Yang algorithm?

Select one:
every process is initially white
a message sent by a white process is colored white
a message sent by a red process is colored red
a process turns red when it receives a marker

Ans: a process turns red when it receives a marker


5. A cut is inconsistent if

Select one:
more than one message cross the cut from the FUTURE to the PAST
any message crosses the cut from the PAST to the FUTURE
at least one message crosses the cut from the FUTURE to the PAST
no message crosses the cut

Ans: at least one message crosses the cut from the FUTURE to the PAST

6. eyjdenotes


Select one:
the set of events that have occurred at process pj
the yth event that has occurred at process pj
the yth internal event that has occurred at process pj
the event at process pj whose time duration is y units

Ans: the yth event that has occurred at process pj

7. For two events a and b having vector timestamps vx and vy respectively, if a causally affects b, then

Select one:
vx = vy
vx > vy
vx || vy
vx < vy

Ans: vx < vy

8. Global state of a distributed system is

Select one:
a collection of the local states of the channels only
a collection of the local states of the processes and the channels
a collection of the local states of the processes only
a collection of the local states of a set of empty channels

Ans: a collection of the local states of the processes and the channels

9. Which of the following properties is not satisfied by scalar clocks?

Select one:
strong consistency
total ordering
consistency
event counting

Ans: strong consistency

10. How many processing modes are defined in Flynn's taxonomy?

Select one:
5
6
3
4

Ans: 4

11. Which of the following is true?

Select one:
send(mij) ∉∉ LSi ⇒ mij ∉∉ SCij ⊕⊕ rec(mij)  ∉∉ LSj

 send(mij) ∉∉ LSi ⇒ mij ∉∉ SCij

 send(mij) ∉∉ LSi ⇒ mij ∉∉ SCij ∧ rec(mij)  ∉∉ LSj


send(mij) ∉∉ LSi ⇒ mij ∉∉ SCij ∨∨ rec(mij)  ∉∉ LSj


Ans: send(mij) ∉∉ LSi ⇒ mij ∉∉ SCij ∧ rec(mij)  ∉∉ LSj

12. Which of the following is true of the UMA model?

Select one:
software is very loosely coupled
interconnection network to access memory may be a multistage switch
processors are of different types
each processor runs a different operating system

Ans: interconnection network to access memory may be a multistage switch

13. A system supporting causal ordering model satisfies

Select one:
for messages mij and mkj , if send(mij) → rec(mkj), then rec(mij) → send(mkj)
for messages mij and mik , if send(mij) → send(mik), then rec(mij) → rec(mik)
for messages mij and mkj , if send(mij) → send(mkj), then rec(mij) || rec(mkj)
for messages mij and mkj , if send(mij) → send(mkj), then rec(mij) → rec(mkj)

Ans: for messages mij and mkj , if send(mij) → send(mkj), then rec(mij) → rec(mkj)

14. The number of processor and memory units in a 5-dimensional hypercube is

Select one:
16
32
25
64

Ans: 32

15. A global state is strongly consistent iff the global state

Select one:
is consistent and transitless
follows the FIFO model
is transitless
follows the causal ordering model

Ans: is consistent and transitless

16. Concurrency of a distributed program is defined as

Select one:
the ratio of the number of local operations to twice the total number of operations
the ratio of the total number of operations to twice the number of local operations
the ratio of the number of local operations to the total number of operations
the ratio of the total number of operations to the number of local operations

Ans: the ratio of the number of local operations to the total number of operations

17. The system of vector clocks is strongly consistent if


Select one:
the dimension of vector clocks is one less than the total number of processes in the distributed computation
the dimension of vector clocks is at least equal to the total number of processes in the distributed computation
the dimension of vector clocks is half of the total number of processes in the distributed computation
the dimension of vector clocks is one third of the total number of processes in the distributed computation

Ans: the dimension of vector clocks is at least equal to the total number of processes in the distributed computation

18. The termination criterion for the Chandy-Lamport global snapshot recording algorithm is that
Select one:
each process has received a marker on all of its incoming channels
each process has sent a marker to every other process
each process has received a marker from each of the other processes
each process has sent a marker on all of its outgoing channels

Ans: each process has received a marker on all of its incoming channels

19. Which of the following is false for a distributed system?

Select one:
has no shared memory
communicate using message passing
individual computers may be connected via LAN or WAN
has a common clock

Ans: has a common clock

20. CORBA stands for

Select one:
Cyclic Obfuscated Request Broker Architecture
Creative Object Request Broker Architecture
Common Object Request Broker Architecture
Coordinated Online Request Broker Architecture

Ans: Common Object Request Broker Architecture

21. For Butterfly and Omega networks, paths from different inputs to any one output constitute a

Select one:
loop
forest
spanning tree
cycle

Ans: spanning tree

22. ei →→ ej  denotes that


Select one:
ei only directly causally affects ej
ei and ej are concurrent
ej directly or transitively causally affects ei
ei directly or transitively causally affects ej

Ans: ei directly or transitively causally affects ej

23. For an n-input and n-output Omega network, output i of a stage is connected to input j of next stage if j = 2i + 1 - n for

Select one:
n/2 < i < n - 1
n/2 < i < n
n/2 <= i <= n - 1
n/2 <= i <= n

Ans: n/2 <= i <= n - 1

24. The number of switches in a single stage of an n-input and n-output Butterfly network is

Select one:
n
n/4
2n
n/2

Ans: n/2

25. A system of logical clocks is strongly consistent if the following condition is satisfied

Select one:
for 2 events ei and ej, ei →→  ej ⇔⇔ C(ei) >= C(ej)

 for 2 events ei and ej, ei →→  ej ⇔⇔ C(ei) = C(ej)

 for 2 events ei and ej, ei ||  ej ⇔⇔ C(ei) < C(ej)

 for 2 events ei and ej, ei →→  ej ⇔⇔ C(ei) < C(ej)

 Ans: for 2 events ei and ej, ei →→  ej ⇔⇔ C(ei) < C(ej)