Distributed Systems MCQ

Distributed Systems:

• Not a feature of Distributed system

  No Shared Resources

  4

• Relation to computer system components

  Communication Network

  2

• Not a Characteristics of Parallel System

  Sequential Process

  4

• What is the main difference between synchronous and asynchronous transmission

  clocking is derived from the data in synchronous transmission.

  3

• The synchronous modems are more expensive than the asynchronous modems because

  they must contain clock recovery circuits

  1

• Asynchronous transmission features

  all the above

  4

• In distributed system each processor has its own

  both local memory and clock

  3

• If one site fails in distributed system

  none of the mentioned

  4

• Network operating system runs on

  server

  1

• Which technique is based on compile-time programtransformation for accessing remote data in a distributed-memory parallel system.

  computation migration

  2

• Logical extension of computation migration is

  process migration

  1

• Processes on the remote systems are identified by

  host name and identifier

  2

• Which routing technique is used in distributed system?

  all of the mentioned

  4

• Distributed OS works on the ________ principle.

  Single system image

  2

• Super computers typically employ _______.

  Multiprocessors OS

  2

• Distributed systems have?

  better resource sharing

  2

• Multiprogramming systems:

  Execute more jobs in the same time period

  3

• In distributed system each processor has its own

  both local memory and clock

  3

• A special unit used to govern the out of order execution of the instructions is called as ______

  Commitment unit

  1

• Network operating system runs on

  Server

  4

• Which routing technique is used in distributed system?

  all of the mentioned

  4

• In distributed systems, link and site failure is detected by

  Handshaking

  2

• If one site fails in distributed system then ___________

  the remaining sites can continue operating

  1

• Which technique is based on compile-time program transformation for accessing remote data in a distributed-memory parallel system?

  computation migration

  2

• Logical extension of computation migration is ___________

  process migration

  1

• Processes on the remote systems are identified by ___________

  host name and identifier

  2

• In distributed system, each processor has its own ___________

  both local memory and clock

  3

• If one site fails in distributed system then ___________

  the remaining sites can continue operating

  1

• Network operating system runs on ___________

  server

  1

• Which technique is based on compile-time program transformation for accessing remote data in a distributed-memory parallel system?

  computation migration

  2

• Logical extension of computation migration is ___________

  process migration

  1

• Processes on the remote systems are identified by ___________

  host name and identifier

  2

• Which routing technique is used in a distributed system?

  all of the mentioned

  4

• In distributed systems, link and site failure is detected by ___________

  handshaking

  2

• The capability of a system to adapt the increased service load is called ___________

  scalability

  1

• Internet provides _______ for remote login.

  telnet

  1

• In distributed systems, a logical clock is associated with ______________

  each process

  2

• If timestamps of two events are same, then the events are ____________

  concurrent

  1

• If a process is executing in its critical section ____________

  any other process can also execute in its critical section

  1

• A process can enter into its critical section ____________

  when it receives a reply message from all other processes in the system

  3

• For proper synchronization in distributed systems ____________

  prevention from the deadlock & starvation is must

  3

• In the token passing approach of distributed systems, processes are organized in a ring structure ____________

  logically

  1

• In distributed systems, what will the transaction coordinator do?

  all of the mentioned

  4

• In case of failure, a new transaction coordinator can be elected by ____________

  bully algorithm

  1

• In distributed systems, election algorithms assumes that ____________

  a unique priority number is associated with each active process in system

  1

• According to the ring algorithm, links between processes are ____________

  unidirectional

  2

• What is Inter process communication?

  allows processes to communicate and synchronize their actions without using the same address space

  2

• Message passing system allows processes to __________

  communicate with one another without resorting to shared data

  1

• Which of the following two operations are provided by the IPC facility?

  receive & send message

  4

• Messages sent by a process __________

  can be fixed or variable sized

  3

• Logical extension of computation migration is ___________

  process migration

  1

• Processes on the remote systems are identified by ___________

  host name and identifier

  2

• Which routing technique is NOT used in a distributed system?

  sequence routing

  4

• The capability of a system to adapt the increased service load is called ___________

  scalability

  1

• Internet provides _______ for remote login.

  telnet

  1

• Writing parallel programs is referred to as

  Parallel programming

  4

• Simplifies application’s of three-tier architecture is ____________.

  Deployment

  4

• Dynamic networks of networks, is a dynamic connection that grows  is  called

  Internet of things

  3

• No special machines manage the network of  architecture in which resources are known as

  Peer-to-Peer

  1

• Significant characteristics  of Distributed systems have of

  3 types

  3

• Data access and storage are elements of  Job throughput, of __________.

  Efficiency

  3

• Billions of job requests is over massive data sets, ability to support known as

  Adaptation

  3

• the various forms of ordering paradigms are

  All of the above

  4

• The Challenges for a distributed system are:

  Process knowledge should be put in place for the administrators and users of the distributed model.

  4

• Types of System Model

  all the above

  4

• Assumptions of Chandy–Lamport’s algorithm

  There are finite number of processes in the distributed system and they do not share memory and clocks.

  1

• Marker receiving rule

  All the above

  4

• Need of taking snapshot

  Checkpointing

  1

• List the snapnot algorithms

  All the above

  4

• Causality in a synchronous execution

  If x occurs before y at the same process, then x y

  1

• Raynal-Schiper-Toueg (RST) Algorithm complexity

  n 2 ints/ process

  1

• Group Communication Issues

  Ordering

  1

• implementing Logical Clocks rules

  Both A and B

  3

• characteristics of Synchronous distributed systems

  the time to execute each step of a process has known lower and upper bounds;

  1

• If e → e ' then L(e) < L(e'), but the converse is not true. Vector clocks address this problem. "A vector clock for a system of N processes is an array of N integers." Vector clocks are updated as follows:

  All the above

  4

• What is common problem found in distributed system ?

  Deadlock problem

  3

• If timestamps of two events are same, then the events are ___________________

  concurrent

  1

• If a process is executing in its critical section, ____________________

  no other process can execute in its critical section

  2

• A process can enter into its critical section __________________

  when it receives a reply message from all other processes in the system

  3

• For proper synchronization in distributed systems ____________

  prevention from the deadlock & starvation is must

  3

• In the token passing approach of distributed systems, processes are organized in a ring structure _______________

  logically

  1

• In case of failure, a new transaction coordinator can be elected by ____________

  Bully algorithm

  2

• In distributed systems, election algorithms assumes that __________________

  a unique priority number is associated with each active process in system

  1

• According to the ring algorithm, links between processes are ______________________

  Unidirectional

  2

• What are the characteristics of mutual exclusion using centralized approach ?

  All of the mentioned

  4

• What are the characteristics of fully distributed approach ? I. When responses are received from all processes, then process can enter its Critical Section II. When process exits its critical section, the process sends reply messages to all its deferred requests. III. It requires request, reply and release per critical section entry IV. One processor as coordinator which handles all requests

  I and II

  4

• What are the advantages of token(with rings) passing approach ? I. One processor as coordinator which handles all requests II. No starvation if the ring is unidirectional III. There are many messages passed per section entered if few users want to get in section IV. One processor as coordinator which handles all requests V. Only one message/entry if everyone wants to get in

  I, II and IV

  2

• Single coordinator approach has the following advantages :

  All of the mentioned

  4

• Which are the two complementary deadlock-prevention schemes using time stamps ?

  The wait-die & wound-wait scheme

  1

• If an old process wants a resource held by a young process, the old one will wait happens in _________

  Wait-die

  1

• If an old process wants a resource held by a young process, the old one will preempt the young process wounded and killed, restarts and wait happens in ___________

  Wound-wait

  2

• In wound-wait If a young process wants a resource held by an old process, the young process will _____

  Wait

  2

• Election message is always sent to the process with _______

  Higher numbers

  3

• Which algorithms are used to handle mutual exclusion in distributed systems?

  All of the mentioned

  4

• Which algorithms are used for selecting a process to act as coordinator or sequencer? I. Centralized algorithm II. Election algorithm III. Ring algorithm IV. Chandy-Misra-Haas algorithm

  II and III

  3

• What is UTC ?

  Universal Coordinated Time

  3

• In Cristian algorithm the time sever is ________

  Passive

  1

• What are the problems of clock synchronization in distributed operating systems ? I. Processses make decision based only on local information II. The relevent information is scattered among multiple machines III. A single point of failure in the system should be avoided IV. No common clock or other precise global time source exists

  I, II, III, IV

  4

• A ____________is a quartz crystal that oscillates at a well-defined frequency.

  Quartz crystal

  2

• The ______________ is used to store a constant value that is decided based on the frequency of oscillation of the quartz crystal.

  Constant register

  3

• What are the characteristics of mutual exclusion using centralized approach?

  All of the mentioned

  4

• What are the characteristics of tightly coupled system? i) Same clock, usually shared memory ii) Communication is via this shared memory iii) Multiprocessors iv) Different clock

  i, ii and ii

  2

• What are the characteristics of tightly coupled system? i) Different clock ii) Use communication links iii) Same clock iv) Distributed systems

  ii, iii and iv

  4

• What are the characteristics of fully distributed approach? i) When responses are received from all processes, then process can enter its Critical Section ii) When process exits its critical section, the process sends reply messages to all its deferred requests. iii) It requires request,reply and release per critical section entry iv) One processor as coordinator which handles all requests

  i and ii

  2

• What are the advantages of token(with rings) passing approach? i) One processor as coordinator which handles all requests ii) No starvation if the ring is unidirectional iii) There are many messages passed per section entered if few users want to get in section iv) One processor as coordinator which handles all requests v) Only one message/entry if everyone wants to get in

  i, ii and iv

  4

• What are the characteristics of atomicity?

  All operations associated are executed to completion or none are performed

  1

• What things are the transaction coordinator is responsible for?

  All of the mentioned

  4

• Which of the following advantages follows the single coordinator approach?

  All of the mentioned

  4

• Which of the following disadvantages follows the single coordinator approach?

  Bottleneck

  1

• What are the disadvantages of majority protocol?

  Complicated implementation

  1

• What are the parts of a global unique identifier?

  Local unique timestamp

  1

• Which are the two complementary deadlock-prevention schemes using timestamps?

  The wait-die & wound-wait scheme

  1

• The wait-for graph is a deadlock detection algorithm that is applicable when ____________

  all resources have a single instance

  1

• An edge from process Pi to Pj in a wait for graph indicates that ____________

  Pi is waiting for Pj to release a resource that Pi needs

  1

• If the wait for graph contains a cycle ____________

  then a deadlock exists

  2

• If deadlocks occur frequently, the detection algorithm must be invoked ________

  frequently

  2

• What is the disadvantage of invoking the detection algorithm for every request?

  considerable overhead in computation time

  3

• A deadlock eventually cripples system throughput and will cause the CPU utilization to ______

  drop

  2

• Every time a request for allocation cannot be granted immediately, the detection algorithm is invoked. This will help identify ____________

  the set of processes that have been deadlocked

  1

• A computer system has 6 tape drives, with ‘n’ processes competing for them. Each process may need 3 tape drives. The maximum value of ‘n’ for which the system is guaranteed to be deadlock free is?

  2

  1

• A system has 3 processes sharing 4 resources. If each process needs a maximum of 2 units then, deadlock ____________

  can never occur

  1

• ‘m’ processes share ‘n’ resources of the same type. The maximum need of each process doesn’t exceed ‘n’ and the sum of all their maximum needs is always less than m+n. In this setup, deadlock ____________

  can never occur

  1

• A deadlock can be broken by ____________

  abort one or more processes to break the circular wait

  1

• The two ways of aborting processes and eliminating deadlocks are ____________

  Abort one process at a time until the deadlock cycle is eliminated

  3

• Those processes should be aborted on occurrence of a deadlock, the termination of which?

  incurs minimum cost

  2

• The process to be aborted is chosen on the basis of the following factors?

  all of the mentioned

  4

• Cost factors for process termination include ____________

  Amount of time a deadlocked process has thus far consumed during its execution

  3

• If we preempt a resource from a process, the process cannot continue with its normal execution and it must be ____________

  rolled back

  2

• The step where in the results stored in the temporary register is transferred into the permanent register is called as ______

  Commitment step

  2

• To _______ to a safe state, the system needs to keep more information about the states of processes.

  roll back the process

  2

• If the resources are always preempted from the same process __________ can occur.

  starvation

  4

• What is the solution to starvation?

  the number of rollbacks must be included in the cost factor

  1

• Each request requires that the system consider the _____________ to decide whether the current request can be satisfied or must wait to avoid a future possible deadlock.

  resources currently available

  1

• Given a priori information about the ________ number of resources of each type that maybe requested for each process, it is possible to construct an algorithm that ensures that the system will never enter a deadlock state.

  maximum

  3

• A deadlock avoidance algorithm dynamically examines the __________ to ensure that a circular wait condition can never exist.

  resource allocation state

  1

• A state is safe, if ____________

  the system can allocate resources to each process in some order and still avoid a deadlock

  2

• A system is in a safe state only if there exists a ____________

  safe sequence

  3

• All unsafe states are ____________

  not deadlocks

  2

• Since it uses the out of order mode of execution, the results are stored in ______

  Temporary registers

  3

• Which of the following sequence is a safe sequence?

  P1, P0, P2

  4

• If no cycle exists in the resource allocation graph ____________

  then the system will be in a safe state

  2

• The resource allocation graph is not applicable to a resource allocation system ____________

  with multiple instances of each resource type

  1

• The Banker’s algorithm is _____________ than the resource allocation graph algorithm.

  less efficient

  1

• The data structures available in the Banker’s algorithm are ____________

  All of the mentioned

  4

• The content of the matrix Need is ____________

  Max – Allocation

  3

• In super-scalar processors, ________ mode of execution is used.

  Out of order

  3

• The sequence <P1, P3, P4, P2, P0> leads the system to ____________

  a safe state

  2

• The ______ plays a very vital role in case of super scalar processors.

  Compilers

  1

• If an exception is raised and the succeeding instructions are executed completely, then the processor is said to have ______

  Imprecise exceptions

  2

• The commitment unit uses a queue called ______

  Record buffer

  1

• The log is a sequence of _________ recording all the update activities in the database.

  Log records

  1

• In the ___________ scheme, a transaction that wants to update the database first creates a complete copy of the database.

  Shadow copy

  1

• The ____________ scheme uses a page table containing pointers to all pages; the page table itself and all updated pages are copied to a new location.

  Shadow Paging

  2

• The current copy of the database is identified by a pointer, called ____________ which is stored on disk.

  Db-pointer

  1

• If a transaction does not modify the database until it has committed, it is said to use the ___________ technique.

  Deferred-modification

  1

• If database modifications occur while the transaction is still active, the transaction is said to use the ___________technique.

  Immediate-modification

  3

• ____________ using a log record sets the data item specified in the log record to the old value.

  Undo

  4

• In the __________ phase, the system replays updates of all transactions by scanning the log forward from the last checkpoint.

  Redo

  2

• The actions which are played in the order while recording it is called ______________ history.

  Repeating

  1

• A special redo-only log record < Ti, Xj, V1> is written to the log, where V1 is the value being restored to data item Xj during the rollback. These log records are sometimes called

  Compensation log records

  3

• The recovery scheme must also provide

  High availability

  1

• Which one of the following is a failure to a system

  Transaction failure

  3

• Which of the following belongs to transaction failure

  Logical error

  3

• The system has entered an undesirable state (for example, deadlock), as a result of which a transaction cannot continue with its normal execution. This is

  Logical error

  3

• The transaction can no longer continue with its normal execution because of some internal condition, such as bad input, data not found, overflow, or resource limit exceeded. This is

  Logical error

  3

• The assumption that hardware errors and bugs in the software bring the system to a halt, but do not corrupt the nonvolatile storage contents, is known as the

  Fail-stop assumption

  4

• Which kind of failure loses its data in head crash or failure during a transfer operation.

  Disk failure

  3

• The failure occurred sufficiently early during the transfer that the destination block remains intact.

  Partial Failure

  1

• The database is partitioned into fixed-length storage units called

  Blocks

  2

• Which of the following causes system to crash

  All of the mentioned

  4

• Which of the following is not a recovery technique?

  Two-phase commit

  3

• Checkpoints are a part of

  Recovery measures

  1

• ....... deals with soft errors, such as power failures.

  failure recovery

  4

• ........... is an essential part of any backup system.

  Security

  3

• Media recovery deals with ...........

  system errors

  3

• For a backup/restore system, ............. is a prerequisite for service in a enterprise.

  Scalability

  4

• Failure recovery and media recovery fall under ........

  system recovery

  3

• The .......... consists of the various applications and database that play a role in a backup and recovery strategy.

  Recovery Manager environment

  1

• In which the database can be restored up to the last consistent state after the system failure?

  Recovery

  2

• A ........... is a block of Recovery Manager(RMAN)job commands that is stored in the recovery catalogue.

  stored script

  4

• The link between two processes P and Q to send and receive messages is called __________

  communication link

  1

• Which of the following are TRUE for direct communication?

  A communication link can be associated with exactly two processes

  2

• In indirect communication between processes P and Q __________

  there is a mailbox to help communication between P and Q

  3

• In the non blocking send __________

  the sending process sends the message and resumes operation

  2

• In the Zero capacity queue __________

  the sender blocks until the receiver receives the message

  2

• The Zero Capacity queue __________

  is referred to as a message system with no buffering

  2

• Bounded capacity and Unbounded capacity queues are referred to as __________

  Automatic buffering

  2

• The throughput of a super scalar processor is _______

  More than 1

  3

• When the processor executes multiple instructions at a time it is said to use _______

  Multiple issues

  4

• In the transaction of five state process models, if a parent terminates, all child processes associated with that parent may be terminated.

  Ready → Exit

  3

• With the use of swapping, an I/O operation, one other state must be added to the process behavior model called the ……………… state.

  Suspend

  4

• When all of the processes in main memory are in …………………. state, the operating system can suspend one process by putting it in the suspend state and transferred to the disk.

  Blocked

  1

• A global system of Interconnected Computer networks is called as

  Internet

  3

• The Ricart & Agrawala distributed mutual exclusion algorithm is

  Less efficient and less fault tolerant than a centralized algorithm

  2

• SRM protocol stands for

  Scalable Reliable Multicasting

  3

• _____________ is a physical clock synchronization Algorithm

  Cristian

  1

• A system that offers intermediate-term storage capacity for messages, without requiring either the sender or receiver to be active during message transmission is suitable for

  Persistent asynchronous communication

  1

• Which of the following is a form of distributed information system?

  Transaction Processing System

  2

• In Raymond’s Algorithm, TOKEN is held by which node of the tree?

  Root node

  3

• Which of the following is a recovery technique?

  Deferred update

  1

• “The approach that is used to devising a randomized leader election algorithm is to use randomization to create asymmetry by having processors choose random pseudo-identifiers, drawn from some range, and then execute a deterministic leader election algorithm.”

  True

  1

• Peer-to-peer (P2P) network systems use ___________________organization of the network overlay for flexibly sharing resources (e.g., files and multimedia documents) stored across network-wide computers.

  Application-level

  4

• In P2P networks, the ongoing entry and exit of various nodes, as well as dynamic insertion and deletion of objects is termed as _______________

  Churn

  2

• Which of these is an example of Unstructured P2P overlay network?

  Gnutella

  4

• What is the characteristic of P2P network?

  All of these

  4

• To keep the GFS (Google File System), highly available there are two strategies used namely _____________ and _____________.

  Fast Recovery , Chunk Replication

  2

• In GFS (Google File System) files are divided in ____________ chunks.

  Fixed Size

  2

• GFS (Google File System) supports following operations:

  read, write , open , close

  4

• In a distributed computing environment, distributed shared memory is used which is_____________

  Logical combination of physical memories on the nodes

  2

• _________ is a DSM system that is fundamentally based on software objects, but which can place each object on a separate page so the hardware MMU can be used for detecting accesses to shard objects.

  Munin

  3

• What is NUMA?

  NON Uniform Memory Access

  2

• What is NORMA?

  no remote memory access

  3

• DSM stands for______________

  Distributed shared memory

  3

• Having data belonging to two independent processes in the same page is called____________.

  False sharing

  4

• _______refers to the block size of the DSM system, i.e. to the units of sharing and the unit of data transfer across the network when a network block fault occurs.

  Granularity

  1

• ________ returns the data item referenced by address and __________ sets the contents referenced by address to the value of data.

  Read, Write

  1

• In distributed system, The Processes access data in the shared address space through the following two basic primitives:

  data = Read (data), Write (address)

  2

• In distributed system, read _________ the data item referenced by address, and write __________ the contents referenced by address to the value of data.

  returns, sets

  2

• ___________ refers to the block size of a DSM system, that is, to the unit of sharing and the unit of data transfer across the network when a network block fault occurs.

  Granularity

  3

• The main problem is to solve the memory coherence problem that deals with the ________________ of a piece of shared data lying in the main memories of two or more nodes.

  consistency

  3

• In the distributed system, data is duplicated mainly for ____________________

  reliability and performance

  2

• _______________ consistency is the most popular and important consistency model.

  Sequential

  1

• The straight-forward model used for the memory consistency is called _____________

  Sequential consistency

  3

• The problem of ___________ may occur when data items in the same data block are being updated by multiple nodes at the same time.

  thrashing

  1

• ______________ occurs when two different processes access two unrelated variables that reside in the same data block

  False sharing

  3

• Therefore, paging overhead is less for ________ block sizes as compared to the paging overhead for _________ block sizes.

  large, small

  2

• An advantage of the use of ____________ approach in shared-memory space is that it is convenient to choose any suitable page size as the unit of sharing and a fixed grain size may be used for all applications.

  no structuring

  2

• In ________________ approach, the shared-memory space is simply a linear array of words.

  no structuring

  1

• In ________________ method, the shared-memory space is structured as a collection of objects.

  structuring by data type.

  3

• In ________________ approach, Shared-memory space is ordered as an associative memory called a tuple space.

  structuring as a database

  2

• Any read to a memory location x returns the value stored by the most recent write operation to x is _____________-

  Strict Consistency

  2

• Writes done by a single process are received by all other processes in the order in which they were issued, but writes from different processes may be seen in a different order by different processes. It is follow in ____________

  PRAM Consistency

  4

• The ____________ model is the strongest form of memory coherence, having the most stringent consistency requirement.

  strict consistency

  3

• A shared-memory system is said to support the __________ model if the value returned by a read operation on a memory address is always the same as the value written by the most recent write operation to that address.

  strict consistency

  2

• In_________________ model, when a process does a release access, the contents of all the modifications are not immediately sent to other nodes but they are sent only on demand.

  release consistency

  1

• Implementation of the ________ model for a DSM system is practically impossible.

  strict consistency

  1

• A shared-memory system is said to support the sequential consistency model if all processes see the ___________ of all memory access operations on the shared memory.

  same order

  1

• A sequentially consistent memory provides __________ semantics because all the processes sharing a memory location always see exactly the same contents stored in it.

  one-copy/single-copy

  3

• In the ________________ model, Memory reference operations that are not potentially causally related may be seen by different processes in different orders.

  causal consistency

  4

• "Correct order" means that if a write operation (w3) is causally related to another write operation (w2) and a write operation (w2) is causally related to another write operation (w1), then the acceptable order is ________________.

  w1, w2, w3

  1

• PRAM means _________________________________

  Pipelined Random-Access Memory Consistency Model

  3

• To enforce ………………….. two functions are provided enter-critical and exit-critical, where each function takes as an argument the name of the resource that is the subject of competition.

  Deadlock

  3

• When the operating system has performed a …………….. operation, it has two choices for selecting a process either admitting a newly created process or bring in a previously suspended process.

  Swapping-out

  2

• In ………………. state, the process is in secondary memory but it is available for execution as soon as it is loaded into main memory.

  Ready/Suspended

  4

• In …………………… state, the process is in secondary memory and awaiting an event.

  Blocked/Suspend

  3

• A process in the ………………….. state is moved to the ……………….. state when the event for which it has been waiting occurs.

  blocked/suspend, ready/suspend

  3

• A process in the ……………….. state is moved to the ………….. state if there are no ready processes, then at least one blocked process is swapped out to make room for another process that is not blocked.

  blocked, blocked/suspend

  1

• A process in the ………………… state is moved to the …………….. when there are no ready processes in main memory, the operating system will need to bring one in to continue execution.

  ready/suspend, ready

  4

• A process will ……………….. while it is running, either because it has completed or because of some fatal fault condition.

  Terminate

  2

• A ……………… process is moved to the ready state when its time allocation expires.

  Running