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Mastering Distributed Systems Quiz
Test your knowledge and understanding of distributed systems with our comprehensive quiz. Covering various topics from concurrency control to cloud services, this quiz will challenge your grasp of the principles that govern distributed environments.
Whether you are a student, a professional, or just someone interested in distributed computing, you will find this quiz insightful and informative. Key areas include:
- Concurrency Control
- Distributed Databases
- System Reliability
- Time-Space Diagrams
Which of the following statements represent false assumptions about a Distributed System?
Latency is zero
Network is reliable
Uses the asynchronous communication model
Topology does not change
Which of the following statements is true about time-space diagrams:
They show the time evolution of a distributed system showing the processes, atomic events execution and the messages exchanged by the processes
Together with the concept of “cut” they define the Lamport scalar time
They show the time usage of the memory space in the distributed system
They help identifying security problems in a distributed system
Which of the following objectives should be achieved by concurrency control algorithms?
Guarantee that multiple transactions can be executed simultaneously while still being isolated
Schedule individual read/write operations as to achieve transaction isolation and consistency
Increase data security and privacy across several transaction
The global state of a distributed system (choose the right answer):
Is represented by the state of all processes and of all communication channels
Is represented by the state of all processes and their sent messages
Is represented by a snapshot of the memory of the distributed system’s processing nodes
Is represented by a snapshot of the messages in transit in the communication channels
Which of the following statements referring to Message Queues communication between processes are correct?
It is a type of direct communication
It is a type of indirect communication
The communication entities must be active at the same time
The communication entities may not be active at the same time
In a transaction related pessimistic concurrency control algorithm (choose the right answer):
Transactions are executed without checking for serializability condition
Transactions operation are synchronized before they are executed
Transactions operation are synchronized after they are executed
Transactions are executed and the check for serializability is done right after committing
The Mean Time To Failure (MTTF) is a measure that is specific to (choose the right answer):
Availability
Performance
Reliability
Consistency
In a Distributed Database Environment, the Global Conceptual Schema contains information about (choose the right answer):
The locations where the individual tables are stored
The database tables, their columns, data types, primary and secondary keys, etc.
How the database tables are fragmented and where the fragments are located
Which of the following statements is true about Chandy-Lamport snapshot algorithm for FIFO channels?
The marker is sent by a site before taking its snapshot
The marker is sent by a site after taking its snapshot
Which of the following statements are true for a P2P system?
A P2P system consists of many server processes and many client processes
A P2P system consists of one server process and many client processes
All P2P processes offer the same interfaces
All P2P processes run the same program
Which of the following statements describe the vertical fragmentation of a database?
Splits a table and groups the columns into fragments
Splits a table and groups the rows based on the values of one or more columns
Splits a tables and groups the rows based on the rows of another table
Splits a tables and groups the rows based on the column of another table
To improve low utilization ratio of server machines in virtual clusters it is recommended to (choose the right answer):
Increase servers' memory
Perform server consolidation
Allocate the execution of the same task on more servers
Add new server machines
Which type of cloud service provides resources allow the users to develop, deploy, and manage the execution of their applications?
Infrastructure as a Service (IaaS)
Platform as a Service (PaaS)
Software as a Service (SaaS)
CAP theorem states that every distributed system can provide only two of the following properties (choose the right answer):
Consistency, Availability, Performance
Consistency, Availability, Partition-Resilience
Consistency, Access, Performance
Concurrency, Availability, Partition-Resilience
Which of the following are true about logical clocks
They capture the event causality in a more accurate way than physical time
They measure the time between two distributed system events
The time measured is expressed in nanoseconds
They can be used to timestamp the events of a distributed system execution
In RPC mode a stub is:
A remote procedure implemented by a server
A proxy of a remote procedure
A server side dispatcher module used to identify the procedure to be executed
Which of the following statements are true in case of full virtualization:
Guest OS knows that it is running in virtualized environment
Guest OS is completely abstracted from the underlying infrastructure
Guest OS is used without any modification
Guest OS is modified to replace non-virtualizable instructions with hypercalls
Bi-directional streaming is (choose the appropriate answer):
A feature of all RPC technologies
A feature of gRPC
A feature of virtualization
Which of the following is a feature of a Distributed System (DS)?
If one node fails, the rest of the DS nodes will stop execution
If one node fails, only the directly connected nodes to the failed node will stop execution
F one node fails, the rest of the nodes will continue to operate
Which of the following represent benefits of resource virtualization?
Elastic usage of hardware resource
Server consolidation
Lower energy consumption
Which of the following statements are true for a Distributed Transaction (DT)?
A DT must be of all or nothing semantics
A DT generates a transition of a database from a consistent state to a consistent state
DT’s effect is transparent to other transactions until it commits
A deadlock situation may occur in all concurrent executed DTs no matter of the concurrency control technique
Which of the following is NOT true about Java RMI?
Parameters can be passed both by reference and by value
The distributed object interface must be deployed both on client and serve
The distributed garbage collector counts both local and remote references to an object
RMI Registry is a reference implementation for a naming service
Which of the following must be satisfied by the global state of a distributed system to be consistent?
Every message recorded as sent by the sender processor should be in the communication channel or already received by the destination process
If a message is not recorded as sent it cannot be in the communication channel or already received
There should be no messages in the communication channels
The order of the sent messages recorded at the sender processes should be the same at the receiving processes.
A database is said to be distributed if (check all true statements):
All its stored data is localized at a single site
Any of its tables are stored at different sites
One or more of its tables are replicated and their copies are stored at different sites
One or more of its tables are fragmented and the fragments are stored at different sites
In a two-phase locking algorithm (check all true statements):
In the Growing Phase, the scheduler acquires all the locks a transaction is needed
In the Growing Phase, the scheduler acquires all the locks needed for write operations
In the Shrinking Phase the scheduler releases the locks as each operation completes
In the Shirking Phase the scheduler releases all locks at once after transaction terminates
Which type of failures are also known as Byzantine failures?
The omission failures
The arbitrary failures
The timing failures
The masking failures
An explicit wait-for graph may be used for implementing (choose the right answer):
A deadlock detection technique for lock-based concurrency control
A deadlock detection technique for optimistic concurrency control
In the One Phase Atomic Commit protocol (check all true statements):
The coordinator takes the commit or abort decision
The participants vote commit or abort
The coordinator together with the participants take the commit or abort decision using voting
The participants cannot decide to abort the transaction on their own
System Throughput is:
An indicator of availability
An indicator of the number of queries/requests per second
An indicator of durability
In transaction implementation technique based on write-ahead logs (check all true statements):
Each of the participant nodes keeps its own log of transaction changes
Only the coordinator keeps a log of transaction changes
The data is effectively changed only after the log is written successfully
The data is changed and then, the modification is written to the log
Which of the followings are true about vertical fragmentation of a table in distributed storage design?
Only one of the fragments must include the primary key column(s) of the original table
All fragments must include the primary key column(s) of the original table.
The fragments may not include the primary key column(s) of the original table.
Vertical fragmentation must allow table re-construction from the fragments
For which type of logical clocks the event timestamp must include the processor index for having a totally ordered events in a distributed system?
Scalar time
Vector time
Both scalar time and vector time
Which of the followings are true about atomic commit protocols in distributed transactions?
Each Participant must call the join() operation defined by the Coordinator interface;
The Coordinator must call the join() operation defined by Participants' interface
In a distributed transaction, the Coordinator must have the references to all Participants;
Check all true statements about Virtual Machines (VMs).
All VMs running on the same server must have the same guest Operating System
VMs can be replicated in multiple servers;
VM instances may be created from a template VM
The virtualization layer provides services for data exchange between VMs
Which of the followings are specific only to distributed deadlocks?
Deadlock situations are detected by using wait-for graphs;
Deadlock situations are detected by using timeout timers;
A phantom deadlock situation may happen during a deadlock detection process;
Concurrency control is the main task of:
Recovery Manager
Data Manager
Scheduler
Transaction Manager
Which of the following is the correct definition of the reliable one to one communication:
Any message in the outgoing message buffer is delivered to the incoming message buffer
The message received is identical to one sent, and no messages are delivered twice
Any message in the outgoing message buffer is delivered to the incoming message buffer and the message received is identical to one sent, and no messages are delivered twice
The transparency type that offers the same interface to a service, no matter if it is local or remote is called:
Access transparency
Location transparency
Migration transparency
Concurrency transparency
Check all true statements about a Global Conceptual Schema (GCS)
Includes how distributed tables are fragmented
Includes storage locations for distributed tables
Includes information about tables replication
Includes all primary keys of the tables
Includes all foreign keys of the tables
Google App Engine (GAE) is a type of:
Infrastructure as a Service
Software as a Service
Platform as a Service
None of the indicated answers
(True or False) Failure is easier to be detected for synchronous distributed systems than for asynchronous distributed systems
True
False
In which type of virtualization technique the guest operating system needs to be modified to be adapted to the hypervisor?
Full Virtualization of type 1
Full Virtualization of type 2
Para-Virtualization
Hardware-assisted Virtualization;
(True or False) In a distributed system, strong consistency of replicated data has a positive impact over latency.
True
False
Check all true statements about a RPC client stub
It should be compiled and linked with the client code
It should be compiled and linked with the server code
It should implement the remote procedure
It is used to achieve the goal of semantic transparency
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Check all true statements about a binding agent used in client - server binding process;
Binding agent location should be known by both servers and clients
Binding agent location should be known only by the clients
Communication overhead is low when most of the clients are short lived;
Replicated binding agents involves high overhead
Replicated binding agents involves low overhead
An interprocess communication where both send and receive operations are blocking operations is called:
Transient communication
Persistent communication
Synchronous communication
Asynchronous communication
Which of the following statements are true about Chandy-Lamport snapshot algorithm?
It works for all types of communication networks;
It works only for specific communication networks;
The marker must be sent by a node after taking its snapshot
The marker must be sent by a node after taking its snapshot
The marker must be sent by a node after taking its snapshot
Which of the followings are true about table fragmentation in distributed storage design:
Table fragments must not be replicated
Table fragments must be stored at different sites
Table fragmentation increases data processing parallelism
Table fragmentation helps in case of disaster recovery
Which of the followings are true about nested distributed transactions?
Children sub-transactions may run on different machines;
Children sub-transactions must run on the same machine;
Children sub-transactions may run in parallel;
For consistency reasons, children sub-transactions must be executed one after the other;
Consider a transaction T operating on an object x and transaction U operating on an object y. Check all true statements below.
T read / U read is a conflicting situation;
T read / U write is a conflicting situation;
T write/ U read is a conflicting situation;
T write / U write is a conflicting situation;
The mentioned operations are not conflicting situations;
Check the true statement
Asynchronous distributed system failures can be detected by using timeout timers;
Synchronous distributed system failures can be detected by using timeout timers
Timeout timers can be used for failure detection in both synchronous and asynchronous distributed systems
Timeout timers can be used for failure detection in both synchronous and asynchronous distributed systems
Which of the followings is true about a flat distributed transaction?
Each transaction operation must be completed before executing another operation;
Each transaction operation must be executed at a different site;
Transaction operations may be executed in parallel;
The unwanted situation that may happen, when the acquired locks are progressively released before transaction execution completion is called:
Lost update situation
Inconsistent retrieval situation
Cascading abort situation
Deadlock situation
Which of the followings is true about the events in a distributed system?
The timestamp of an event represents the physical time when the event happened
Concurrent logical events must occur at the same physical time
Logically concurrent events are not causally related events;
Which ACID property describes the fact that all transaction effects should be saved into permanent storage after the successful transaction commit.
Consistency
Isolation
Durability
Atomicity
Which of the followings are features of Optimistic Concurrency Control (OCC) technique?
It is recommended for private workspace transaction implementations;
It is recommended for write-ahead log transaction implementations;
There are no conflicts in OCC, hence all concurrent transactions may commit without any validation;
In OCC all transactions must be validated before they are allowed to comm
Which of the followings represent benefits of resource virtualization?
Server consolidatio
Elastic usage of hardware resource
Avoids single points of failure
Limited infrastructure and resource demand
(True or False) Data replication improves data consistency.
True
False
The ability of a distributed system to limit the latency due to system faults is called:
Reliability
Consistency
Availability
Efficiency
Which of the following statements are true about the atomic Two-Phase Commit Protocol (2PC) for Distributed Transactions?
The participants must save the involved transaction data into permanent storage before voting commit;
The participants must save the involved transaction data into permanent storage after voting commit;
Each protocol step defines a timeout timer for avoiding algorithm blocking;
The coordinator may decide to commit the transaction even if a participant voted abort;
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