CS 4113 Midterm

Enterprise Java Beans(EJB), described under Note 3.7 in the textbook, provides an interface for underlying services implemented by the application server. Which definition below accurately defines a stateless session bean found from the text? A.) "is an object that is invoked once, does its work, after which it discards any information it needed to perform the serviceis offered to a client." B.) "maintains client-related state...when the client is finished (possibly having invoked the object several times), the bean will automatically be destroyed." C.) "considered to be a long-living persistent object...stores information that may be needed a next time a specific client accesses the server." D.) "is used to program objects that react to sending and receiving messages...contains application code for handling the message, after which the server simplydiscards it."

"is an object that is invoked once, does its work, after which it discards any information it needed to perform the serviceis offered to a client."

According to the textbook, in a network file system, what is a Remote Procedure Call? a) Component responsible for handling access to files stored at a remote server. b) Component responsible for handling incoming client requests. c) A standardized way to let a client machine make an ordinary call to a procedure that is implemented on another machine d) Idea that each file server provides a standardized view of its local file system.

A standardized way to let a client machine make an ordinary call to a procedure that is implemented on another machine

According to van Steen and Tanenbaum, which of the following is FALSE about a stateful server. A) A file server is a stateful server and it maintains a table of file,client entries. B) A stateful server maintains persistent information about its clients. This information about the clients is explicitly deleted by the stateful server C)A stateful server keeps track of the permissions it has issued to its set of clients which improves the performance of read & write operations. D) A stateful server can resume effectively to its previous state with no loss of information after any sudden crash.

A stateful server can resume effectively to its previous state with no loss of information after any sudden crash.

According to van Steen and Tanenbaum, a clock that captures not only the ordering of events but also the causality of events is a: A) Global clock B) Logical clock C) Vector clock D) Reference clock

A) Vector clock

According to the text book, the mutual-exclusion algorithm described in the table is? Messages per entry/exit = 2*m*k+m Delay before entry (in message times) = 2*m*k A.Decentralized B.Token ring C.Distributed D.Centralized

A. Decentralized

According to Van Steen and Tanenbaum, which of the following forms of scalability is the most difficult to solve, and why? A) Size scalability, because the machines are incapable of handling the work. B) Administrative scalability, because it deals with nontechnical issues, such as the politics of an organization and human collaboration. C) Geographical scalability, because the issues arising from network latency. D) Geographical scalability, because the occurrence of data replication and inconsistency.

Administrative scalability, because it deals with nontechnical issues, such as the politics of an organization and human collaboration.

According to van Steen and Tanenbaum, which of the following is correct about connection-oriented service : A) The sender first has to setup a connection with the receiver to send a message. B) The connection stays even after the exchange of data is done. C) Before sending data the sender and receiver first explicitly establish a connection, and possibly negotiate specific parameters of the protocol they will use. D) There is no need to setup before starting the communication process.

Before sending data the sender and receiver first explicitly establish a connection, and possibly negotiate specific parameters of the protocol they will use.

According to the textbook, which mutual-exclusion algorithm is widely applied due to its simplicity and efficiency? A.) Distributed B.) Decentralized C.) Centralized D.) GPS

Centralized

According to Van Steen and Tanenbaum, which of the following is a potential downside to choosing a hierarchical peer-to-peer model? A. Because managing super peers takes considerable resources, searching in hierarchical architectures actually takes more time than in non-hierarchical ones. B. There is no way to handle super peers malfunctioning. C. Security becomes exponentially harder in a hierarchical architecture. D. Choosing which nodes should be super nodes can be a challenging problem.

Choosing which nodes should be super nodes can be a challenging problem.

Suppose there is a distributed system that uses a distributed algorithm mutual exclusion technique, so that a process needs permission from every other process in order to access a shared resource, and suppose that process A sends out a message requesting the use of resource x.Suppose process B also wants to access resource x but has not done so yet.According to Van Steen and Tanenbaum, how should B respond to A's message? A)Queue the request and do not reply B) Compare the timestamp of the incoming message with the timestamp of the message it sent in order to determine the appropriate action C) Send back an OK message D) Send back a Permission Denied message

Compare the timestamp of the incoming message with the timestamp of the message it sent in order to determine the appropriate action

According to van Steen and Tanenbaum which one of the following is correct about a Layered Architecture? A) Components are organized in a layered fashion where a component at layer Lj can make a downcall to a lower layer Li (i < j) and expects a response. In exceptional cases upcall is made. B) Lower layer Li components always make a upcall to a higher layer Lj where (i < j). C) In a down call, a higher layer always makes a request to a layer just below it. D) In a Layered communication-protocol stack, the layer interface should not hide the implementation of the service.

Components are organized in a layered fashion where a component at layer Lj can make a downcall to a lower layer Li (i < j) and expects a response. In exceptional cases upcall is made.

According to the textbook, what is the interface responsible for in an object? A. Remembers relevant information. B. Conceals implementation details allowing us to consider an object independent of the environment. C. Marshals a method and send a stream of bytes to the server to be unmarshaled. D. Unmarshals a received stream of bytes.

Conceals implementation details allowing us to consider an object independent of the environment

Asper text book, Remote procedure calls have been widely adopted as the basis of middleware and distributed systems in general. Which of the following is true about the DCE RPC ( Distributed Computing Environment RPC) A. The programming model underlying DCE is not a client-server model. B. The existing applications would be affected if customer add the DCE to a collection of machines and try to execute it as a distributed applications. C. DCE is a true middleware system. It is designed to be executed as a layer of abstraction between distributed applications and existing network. D.As RPC can hide details, clients and servers are highly dependent of one another and can't be written in different programming languages

DCE is a true middleware system. It is designed to be executed as a layer of abstraction between distributed applications and existing network.

For the Distributed System to be scalable it is very important to have a decentralized algorithm for collecting and transporting all the input and output information. Why can't it be assumed that there is an implicit global clock for such algorithms? A) International Laws B) Easy to get all the clocks synchronized. C) Distributed systems use their own clock. D) Distributed systems use their own clock, so it is almost Impossible to get all the clocks synchronized.

Distributed systems use their own clock, so it is almost Impossible to get all the clocks synchronized.

According to van Steen and Tanenbaum, _________ is the service in the distributed environment to find a network address with regards to the name of the network. A) Internet Protocol System (IPS) B) Domain Name System (DNS) C) Transport Protocol System (TPS) D) Transmission Control Protocol (TCP)

Domain Name System (DNS)

According to Van Steen and Tanenbaum, which of the following statements about Unstructured peer-to-peer systems are FALSE? (A) Random walk imposes much less network traffic, yet it may take much longer before a node is reached that has the requested data. (B) Flooding can be very expensive because every time we are requesting a data item to all the neighbors and hence a request often has an associated time-to-live (TTL) value. (C) In policy-based search methods, a node may decide to keep track of peers who responded positively and turn them into preferred neighbors for succeeding queries. (D) Flooding is more efficient when compared with the random walk because number of node visits will be less and therefore less time to complete the work.

Flooding is more efficient when compared with the random walk because number of node visits will be less and therefore less time to complete the work.

As per the textbook, basic idea behind Remote Procedure Call is to make a remote procedure call look like a local one. Which of the following is true about Remote Procedure Calls (RPC)? A. An RPC is not ideal for client-server applications B. When a client calls a remote procedure, the client is not blocked until a reply is returned from server. C. The client and the server don't have to agree on representation of simple data structures, such as integers, characters, Booleans, etc. D. For RPC to work properly, the caller and the callee should follow same protocol. Both the sides should agree on steps to follow and format of exchanged messages.

For RPC to work properly, the caller and the callee should follow same protocol. Both the sides should agree on steps to follow and format of exchanged messages.

According to Van Steen, which of the following are true about grid-computing systems? a. The layered architecture of a grid-computing system consists of 3 layers, a resource layer, a fabric layer, and a collective layer. b. Grid-computing is used, in virtually all cases, for parallel programming in which a single program is run in parallel on multiple machines. c. Grid computing is characterized by an easily usable and accessible pool of virtualized resources where resources can be configured dynamically. d. For a grid-computing system, there are no assumptions are made about the similarity of hardware, operating systems, networks, administrative domains, or security policies.

For a grid-computing system, there are no assumptions are made about the similarity of hardware, operating systems, networks, administrative domains, or security policies.

According to the textbook, how do a web server and browser communicate? A. HTTP request is sent from the browser to the server to fetch a document. B. HTTP request is sent from the browser to the web server to fetch a document. C. URL, specifying the document info, communicates between the Browser and the web server D. The network file system is responsible for communication between the web server and the browser.

HTTP request is sent from the browser to the web server to fetch a document.

According toVan Steen and Tanenbaum, which of the following peer-to-peer architectures relies on a connection between weak peers and super peers? A) Structured peer-to-peer systems B) Unstructured peer-to-peer systems C) Hierarchical peer-to-peer systems D) Distributed peer-to-peer systems

Hierarchical peer-to-peer systems

Roadside Inc. produces robotic wheels that turn depending on given inputs from a control unit. Mother Brain Industries designs control units to be used with robotic wheels. Both manufacturers agree to a common standard for communication between their products, without publishing the specifics of their codebases implementation of functions. According toVan Steenand Tanenbaum, what is this an example of? A) Interoperability, because it is an example of two separate systems fromdifferent manufacturers operating together by relying oneach other's services as defined by a agreed upon standard. B) Interoperability, because it is an example of an application written for one system being run on a different system with no/minimal changes. C) Portability,because it is an example of two separate systems from different manufacturers operating together by relying oneach other's services as defined by a agreed upon standard. D) Portability, because it is an example of an application written for one system being run on a different system with no/minimal changes.

Interoperability, because it is an example of two separate systems fromdifferent manufacturers operating together by relying oneach other's services as defined by a agreed upon standard.

According to the textbook, wrappers are one of the design patterns of middleware to promote openness. What is a wrapper? A. A software construct that will break the usual flow of control and allow other (application specific) code to be executed. B. Is a special component that offers an interface acceptable to a client application, of which the functions are transformed into those available at the component. C. Helps in updating the middleware through dynamically constructing middleware from components. D. A component that allows applications to invoke remote objects.

Is a special component that offers an interface acceptable to a client application, of which the functions are transformed into those available at the component.

Which of the following is true about token-based algorithms to mutual exclusion? A. Token-based algorithms commonly cause starvation. B. For token based algorithms, a process wanting to access a shared resource first requires the permission from other processes. C. It is one of the two classifications of distributed mutual exclusion algorithms, the other being permission based. D. Token-based algorithms often have multiple tokens to access a shared resource.

It is one of the two classifications of distributed mutual exclusion algorithms, the other being permission based.

According to Van Steen in the Distributed Systems textbook, in the context of the architecture of grid computing, what is the fabric layer? A) Layer that consists of the applications that operate within a virtual organization. B) Layer that consists of communication protocols for supporting grid transactions that span the usage of multiple resources. C) Layer responsible for managing a single resource. D) Layer that provides interfaces to local resources at a specific site.

Layer that provides interfaces to local resources at a specific site.

According to Van Steen and Tanenbaum, which of the following is NOT true of a structured peer-to-peer system? (A) A client or server may be physically split into logically equivalent parts, but each part is operating on its own share of the complete data set. (B) Logically different components should be placed on different machines, such as separating user interface, processing components, and data management components. (C)The system can be represented by a network in which the nodes are formed by the process and the links represent the possible communication channels. (D) The system usually employs a semantic-free index.

Logically different components should be placed on different machines, such as separating user interface, processing components, and data management components.

According to the textbook, there is a design issue serverswhether a server is stateless or not. Where are stateful, stateless, and soft state servers. What is a stateless server? A) Means maintaining persistent information on its clients. B) The server promises to maintain state on behalf of the client, but only for a limited time. C) Meaning does not keep information on the state of its clients, and can change its own state without having to inform any client. D) Contains a small piece of data containing client information.

Meaning does not keep information on the state of its clients, and can change its own state without having to inform any client.

According to Van Steen and Tanenbaum, which of the following pieces of information would NOT be part of a thread context? A) Memory maps B) The program counter C) Whether the thread is currently blocked by a mutex D) The stack pointer

Memory maps

As described by Van Steen and Tanenbaum, which of the following is a characteristic of a RESTful architecture? A) Messages to and from a service are fully self-described B) Resources can be named using a variety of different naming schemes C) The four operations available in a RESTful architecture are PUT, GET, READ, and WRITE D) Components maintain a history containing information about callers

Messages to and from a service are fully self-described

According to van Steen and Tanenbaum, which of the following statement about OSI layers is incorrect? (A) Data link layer: Provides the means to detect and possibly correct transmission errors. (B) Network layer: Contains the protocols for routing a message through a computer network. (C) Presentation layer: Prescribes how data is represented in a way that is independent of the hosts on which communicating applications are running. (D) Mobility layer: Mainly contains the protocols for directly supporting applications.

Mobility layer: Mainly contains the protocols for directly supporting applications.

According to Van Steen and Tanenbaum, which of the following statements about threads are not correct? (A) Multithreading always leads to a performance gain. (B) In the case of threads, no attempt has been made to achieve a high degree of concurrency transparency. (C) Multithreading helps in exploiting parallelism when executing the program on a multiprocessor or multicore system. (D) Large applications can also be constructed such that different parts are executed by separate threads.

Multithreading always leads to a performance gain.

According to van Steen, which of the following is NOT a type of peer-to-peer system? A) Multitiered Peer-To-Peer System B) Hypercube Peer-To-Peer System C) Structured Peer-To-Peer System D) Non-Structured Peer-To-Peer System

Multitiered Peer-To-Peer System

Which of the following nodes can be referred as super peers in Hierarchically organized peer-to-peer networks? a.)Nodes that are not organized in a peer-to-peer network b.)Nodes would not maintain an index of the data items. c.)Nodes that maintain the data on resource usage and availability for the nodes of the network that are in each other's proximity. d.) Nodes referred as super peers are short lived processes with high availability

Nodes that maintain the data on resource usage and availability for the nodes of the network that are in each other's proximity.

According to Dr. Dhall's lecture, which of the following statement is FALSE. (A) Obermarck's Path Pushing Algorithm doesn't detect phantom deadlock. (B) InHo-Ramamoorthy 2-phase algorithm, a cycle in WFG doesn't necessarily imply a deadlock exists. (C) Efficient resolution of deadlock requires knowledge of all processes and resources involved. (D) In centralized deadlock detection algorithm, we use central coordinator to maintain graph for the entire state.

Obermarck's Path Pushing Algorithm doesn't detect phantom deadlock.

According to the textbook, which threading model describes a model in which all threads are schedulable entities that are executed in the operating system's kernel? A. One-to-one threading model B. One-to-many threading model C. Many-to-One threading model D. Many-to-many threading model

One-to-one threading model

According to Van Steen and Tanenbaum, which of the following is NOT a property of all transactions? A) Parallelizable B) Atomic C) Durable D) Isolated

Parallelizable

According to Van Steen, which of the following scaling techniques involves taking a component and splitting it up in to smaller parts and subsequently spreading across the system? A. Partitioning and Distribution B. Hiding communication latencies C. Replication D. Caching E. Geographical Scalability

Partitioning and Distribution

According to Van Steen and Tanenbaum, what is the main reason for performing a process migration? A) Mobility B) Flexibility C) Security D) Performance

Performance

Which of the following is not a Clock synchronization algorithm mentioned by Van Steen and Tanenbaum? A) The Berkeley algorithm B) Network Time Protocol (NTP) C) Precision Time Protocol (PTP) D) Reference broadcast synchronization(RBS)

Precision Time Protocol (PTP)

According to van Steen and Tanenbaum, what is the key difference between the concepts of precision and accuracy? A. Accuracy measures the deviation between the clocks of two machines inside of a distributed system, while precision refers to the measure of deviation from an outside reference point, like UTC. B. Precision measures the deviation between the clocks of two machines inside of a distributed system, while accuracy refers to the measure of deviation from an outside reference point, like UTC. C. Precision and accuracy both measure the derivation between the clocks of two machines inside a distributed system, but accuracy is more strict. D. Precision and accuracy both measure the derivation between the clocks of two machines inside a distributed system, but precision is more strict. E. It's all meaningless because time is a tool invented by thestate to suppressus.

Precision measures the deviation between the clocks of two machines inside of a distributed system, while accuracy refers to the measure of deviation from an outside reference point, like UTC.

In an operating system, which of the following is FALSE about Process Control Block (PCB)? (A) Maintain the data needed for the process (B) Process priority (C) Process state (D) Process communication

Process communication

According to the guest lecture by Dr. Pierre St. Juste, what is the main difference between JSON and Protobufs? A) JSON is more computationally efficient than Protobufs B) Protobufs are abstractions from objects implemented in other languages. C) Protobufs are static, which means they can be optimized at compile time. JSON is dynamic. D) Protobufs are language agnostic, while JSON is language dependent

Protobufs are static, which means they can be optimized at compile time. JSON is dynamic.

In a multi-threading environment, when two or more threads access shared memory and try to update the memory at the same time leading to different values of the shared memory.This leads to which of the following issues? a) LiveLock b) DeadLock c) Race Condition d) Starvation

Race Condition

Which of the following does NOT represent a problem with replication in geographically widely dispersed systems? a.) Modifying a copy creates inconsistencies and affects the scalability of the system. b.) Global synchronization makeslarge-scale solutions improbable due to communication delays and implementation complexity. c.) Replication across a distributed system can limit communication latency between nodes. d.) Replication requires global updating on each modification to keep consistency across files.

Replication requires global updating on each modification to keep consistency across files.

According to Van Steenand Tanenbaum, a Network File System (NFS) is a solution for file server to provide a standardized view of its local system. Which of the following statements about NFS is correct? A) Using the remote access model, the file is transferred from the server to the client and uploaded back again after modification. B) The upload/download model is used to exchange commands between server and client. C) Clients can access files on the file server only if the OS is the same. D)The client-server communication is done through RPC (Remote Procedure Calls).

The client-server communication is done through RPC (Remote Procedure Calls).

Which of the following statements is not a specification of the Transmission Control Protocol (TCP)? A.The protocol specifies what needs to be done to preserve the ordering of transferred data. B.The protocol specifies which messages are to be exchanged for setting up or tearing down a connection. C.The protocol specifies the active nodes that have (chunks of) the requested file. D.The protocol specifies what both parties need to do to detect and correct data that was lost in transmission.

The protocol specifies the active nodes that have (chunks of) the requested file.

According to the textbook, there are several ways to organize a server. How is the iterative server organized? A) By storing a piece of information in the client's browser. B) Does not handle the request itself, butpasses it to a separate thread or another process, after which it immediately waits for the next incoming request. C) Doesn't keep information about the client and can change its own state without letting the client know. D) The server itself handles the request and, if necessary, returns a response to the requesting client.

The server itself handles the request and, if necessary, returns a response to the requesting client.

Poslad, roughly describes the core requirements of a Ubiquitous Computing System, and lists them as follows: Distribution, Interaction, Context awareness, Autonomy, and Intelligence.From a distributed-system perspective, the basic concept of Autonomy is: a. A system's ability to characterize the situation of entities that are relevant to the interaction between a user and application. b. Systems should employ advanced algorithms and models to handle incomplete input, quickly react to a changing environment, handle unexpected events, etc. c. The system should react automatically to changes, and manual intervention in the system should be kept to a minimum. d. The devices and other computers forming the nodes of a system are simply networked and work togetherto form a single coherent system. e. The system's ability to take all implicit and explicit interactions into account and react accordingly.

The system should react automatically to changes, and manual intervention in the system should be kept to a minimum.

According to Van Steen, which of the following is true about the Berkeley algorithm? A )The time daemon's time is set automatically. B) Itis suitable for a system in which machines have UTC receivers. C) The time server polls every machine from time to time to ask what time it is there. D) It is not sufficient that all machines agree on the same time.

The time server polls every machine from time to time to ask what time it is there.

Which of the following is a correct assumption to make when developing a distributed application? A) Latency is 0 B) The topology of the network does change C) The network is homogeneous D) The network is reliable

The topology of the network does change

According to Van Steen, an important class of distributed systems is the one used for high-performance computing tasks. What is cluster computing? A. Providing the facilities to dynamically construct an infrastructure and compose what is needed from available services. B. This subgroup consists of distributed systems that are often constructed as a federation of computer systems, where each system may fall under a different administrative domain, and may be very different when it comes to hardware, software, and deployed network technology. C. The underlying hardware consists of a collection of similar workstations or PCs, closely connected by means of a high-speed local-area network. In addition, each node runs the same operating system. D. A group of computers computing the same problem.

The underlying hardware consists of a collection of similar workstations or PCs, closely connected by means of a high-speed local-area network. In addition, each node runs the same operating system.

According to van Steen, which of the following is true regarding the degree of distribution transparency: A) There exists a trade-off between a high degree of transparency and the performance of a system. (B) Aiming for distribution transparency should always be the main goal. (C) When distribution transparency is impossible, we should pretend it is feasible. (D) If replicas of a system are located very far away (i.e. different continents), for any given system update the user should not be aware of the fact that the system is distributed.

There exists a trade-off between a high degree of transparency and the performance of a system.

Van Steen explains 4 coordination models; which of the following is true for the mailbox coordination model? A. Communicating processes do not need know each other explicitly. B. The mailbox coordination model is also known as the shared data space model. C. There is no need for communicating processes to be executing at the same time for coordination to occur. D. Processes publish notifications describing the occurrence of events.

There is no need for communicating processes to be executing at the same time for coordination to occur.

According to the textbook, which general type of mutual exclusion algorithm functions by passing a special message between the processes? A) Permission-Based Algorithms B) Centralized Algorithm C) Distributed Algorithm D) Token-Based Algorithms

Token-Based Algorithms

According to van Steen and Tanenbaum which of the following is the Internet Transport Protocol? A) File Transfer Protocol (FTP) B) Universal Datagram Protocol (UDP) C) Transmission Control Protocol (TCP) D) Trivial File Transfer Protocol(TFTP)

Transmission Control Protocol (TCP)

According to the Lamport's logical clock, if two events A and B happen in two different processes then: A) A --> B B) B --> A C) can't tell D) A and B happen in the same time

can't tell

According to Van Steen andTanenbaum, a server that accepts requests, passes them off to another thread or process, and then continues waiting for incoming requests is known as a: A) iterative server B) concurrent server C) stateful server D) stateless server

concurrent server

Which one from the following is the correct stepsof establishing a TCP socket communication on the server side? A) create Socket -> bind the socket to an address -> listen for connections -> accept a connection -> send andreceive data ->close the connection B) create Socket ->send and receive data C) create Socket -> listen for connections -> accept a connection -> send and receive data -> close the connection D) create Socket -> bind the socket to an address -> send and receive data

create Socket -> bind the socket to an address -> listen for connections -> accept a connection -> send andreceive data ->close the connection

According to the textbook, what is the new problem that peer-to-peer networks have to deal with? A. capacity of the network to manage big system B. unstable behavior of super peer and its back up issue C. how to select node to be come super peer D. flexible for weak peer to connect to different super peer.

how to select node to be come super peer

According to van Steen and Tanenbaum, an RPC that can be be repeated multiple times without harm (because it does not modify the state of the system) is referred to as: A) at-most-once B) idempotent C) a multicast RPC D) anasynchronous RPC

idempotent

According toVan Steen and Tanenbaum, to maintain the state(consistency) of the system, if an operation is requested by a client to the server multiple times, it should not harm the system. These operations are called what? A) idempotent operations B) secured operations C) reliable operations D) atomic operations

idempotent operations

According to the text book, which of the following is not one of the three most important communication patterns supported by ZeroMQ? A.pipeline B.request-reply C.publish-subscribe D.message-passing

message-passing

According to section 4.1 in the textbook, which of the following is the best description of persistent communication? A) the sender is allowed to continue immediately after the message has been submitted for transmission B) no storage facilities are offered, so the receiver must be prepared to accept the message when it is sent. C) neither the sender nor the receiver needs to be up and running for message transmission to take place D) the sender is blocked at least until a message has beenreceived

neither the sender nor the receiver needs to be up and running for message transmission to take place

There are two important types of design patterns that often applied to the organization of middleware: wrappers and interceptor. What does wrapper use for? A. offer an interface acceptable to a client application, of which the functions are transformed into those available at the component. B. handles all the accesses between different applications C. break the usual flow of control and allow other code to be executed D. assist in transferring the invocation to the target object

offer an interface acceptable to a client application, of which the functions are transformed into those available at the component.

What will happen with the message after submitted by persistent communication combine with synchronous communication? A.stored by the communication system only as long as the sending and receiving application are executing and it will block the sender from submitting a new message B. stored by the communication middleware as long as it takes to deliver it to the receiver and it will block the sender from submitting a new message C. stored by the communication middleware as long as it takes to deliver it to the receiver and sender can keep submitting a new message D. stored by the communication system only as long as the sending and receiving application are executing and sendercan keep submitting a new message

stored by the communication middleware as long as it takes to deliver it to the receiver and it will block the sender from submitting a new message

According to the OSI model, beginning on page 164 in the textbook,communication protocols are divided into seven layers. Which definition below accurately defines the Physical Protocol? A.) "Prescribes how data is represented in a way that is independent of the hosts on which communicating applications are running." B.) "Provides support for sessions between applications." C.) "Deals with standardizing how two computers are connected and how 0s and 1s are represented." D.) "Provides the means to detect and possibly correct transmission errors, as well as protocols to keep a sender and receiver at the same pace"

"Deals with standardizing how two computers are connectedand how 0s and 1s are represented."

According to the textbook, all hardware clocks (and consequently software clocks) are subject to "clock drift." What is the typical clock drift rate? A. 10 milliseconds per second B. 10^-6seconds per second C. 10^-9seconds per second D. 50 nanoseconds per second

10^-6seconds per second

According to Van Steen and Tanenbaum, which of the following values of dCp(t)dt corresponds to a fast clock? A) 2 B) 1 C) 0.5 D) 0

2

According to the book, in most cases a server cluster is logically organized into how many tiers? A. 2 B. 3 C. 4 D. 5

3

What is a solution for the problem of bottleneck in the context of stateful servers? A. mix user-level and kernel-level threads B.Using threads instead of processes C. A TCP handoff D. Use a separate port for urgent data

A TCP handoff

According to Van Steen and Tanenbaum, a multicast/broadcast communication is used to send data to multiple receivers in distributed systems. Which of the following statements about multicasts/broadcasts is correct? A) Epidemic protocols are the same as a simple Broadcast. B) Multicast means that the message is sent to every node in the network. C) A naive approach to send data to every node in the network is to apply flooding. D) Deleting a data item in an epidemic algorithm is simple.

A naive approach to send data to every node in the network is to apply flooding.

According to Van Steen and Tanenbaum, which of the following design provides the most openness for middleware? A) Modifiable middleware B) Wrappers C) Interceptors D) Brokers

A) Modifiable middleware

According to Van Steen, one characteristic of a distributed system is the fact that, to users, all individual computing elements should act as a single coherent system. A way to accomplish this is by distribution transparency, one type of which is relocation transparency. What is an example of relocation transparency? A. The fact that a user of the system should not be able to determine where an object is physically located based on how they're accessing it logically. B. The idea that the system should not operate differently if workloads were to be moved from one data center to another. C. If a system supports users moving from one geographical location to another while their existing processes and communications are not affected by this movement. D. The fact that a system might be exist in multiple data centers so that the system can fail over to a different location without the user realizing.

According to Van Steen, which of the following scaling techniques involves taking a component and splitting it

Newman (1994) says Scalability of a system can be measured along at least three different dimensions. One of them being size scalability. What is size scalability? A. An increase in users and resources doesn't have a negative impact on performance. B. users and resources may lie far apart, but the fact that communicationdelays may be significant is hardly noticed. C. system can still be easily managed even if it spans many independent administrativeorganizations. 5 D. acontainer of commonly used components and functions that need not be implemented by applications separatel

An increase in users and resources doesn't have a negative impact on performance.

According to the information presented in the book, what is a downside to using the Berkeley algorithm for time synchronization? A. Every node in the network must have a UTC receiver. B. An operator must manually enter the correct time periodically for accurate time keeping.. C. Every node must periodically ask the time server for the correct time. D. The algorithm assumes a strict hierarchy of nodes.

An operator must manually enter the correct time periodically for accurate time keeping.

According to section 3.2 in the textbook, why is virtualization important? A) Because hardware changes faster than software B) modify guest OS, either by preventing nonprivileged sensitive instructions or making them nonsensitive C) does not isolate failed components D) hide network latency by reacting to the next request while the previous one is being replied

Because hardware changes faster than software

According to Dr.Dhall's lectures, which class of deadlock detection suffers from large communication delays? A) Hierarchical Deadlock Detection B) Distributed Deadlock Detection C) Centralized Deadlock Detection D)Global State Deadlock Detection

Centralized Deadlock Detection

According toDr. Pierre St. Juste's lecture, which of the requirements for distributed design (Network, Functions, Data) are protocol buffers directly tie to, as opposed to gRPC? A) Network B) Network & Functions C) Data & Functions D) Data

Data

According to Van Steen and Tanenbaum, distributed systems should be open.Which of the following is an important step in providing openness? A)Obscuring where an object is physically located on the system from users B)Defining services through interfaces using an Interface Definition Language (IDL) C)Ensuring that applications needing a certain service are all implemented in the same way D)Never assuming that latency is zero E)Learning to trust people again even though you've been hurt before

Definingservices through interfaces using an Interface Definition Language (IDL)

According to Van Steen, which of the following is true about Web browsers in the context of multithreaded clients? A) When using a multithreaded client, browser connections cannot be set up to different replicas , therefore the data cannot be transferred in parallel. B) If a browser is developed as a multithreaded client, separate threads can be activated before the main HTML file is fetched. C) Developing a browser as a multithreaded client is a good idea. D) When using a multithreaded client and a replicated server, the entire Web document takes more time to be displayed than in the case with a non replicated server.

Developing a browser as a multithreaded client is a good idea.

According to the textbook, a server cluster is typically organized into 3 tiers. What does the 3rd tier consist of? A) Front end B)Application/compute servers C) Logical switch D) Distributed file/database system

Distributed file/database system

According to van Steen and Tanenbaum, a distributed system in which it is easy to add new components or replace existing ones without affecting those components that stay in place is considered: A. Portable B. Extensible C. Interoperable D. Scalable

Extensible

According to Van Steen and Tanenbaum, the integration of enterprise applications is an important goal for many middleware products. There are different ways to integrate such applications. Which of the following methods is NOT correct? A) Bootloader B) Shared database C) Remote procedure call D) File Transfer

File Transfer

According to Van Steen, what is something that Interface Description Languages (IDLs) help with? A. Defining the message format for an RPC. B. Generating client and server stubs. C. Determining encoding rules for the RPC message. D. Implementing a communication service.

Generating client and server stubs.

19Van Steen describes peer-to-peer systems as "a class of modern system architectures that support horizontal distribution," which is a way to refer to the way that clients and servers are distributed. There are two main types of peer-to-peer systems: structured and unstructured. If you wanted to build a structured peer-to-peer system, how would you implement the process of searching for the data needed? A. Having a node pass a request for data to all of its neighbors, who repeat the same process until the data is found and is passed up to the original requestor. B. Implementing a distributed hash table, in which each node has its own unique identifier. A requesting node passes the data item's key through a lookup function, and the node where the data item is stored is returned. C. Using a broker that keeps data on resource usage and availability for a nodes in a similar geographic region to optimize storage location. D. Making a node pass a request for data to a random neighbor, who, if itself does not contain the data, will repeat the process until it is found.

Implementing a distributed hash table, in which each node has its own unique identifier. A requesting node passes the data item's key through a lookup function, and the node where the data item is stored is returned.

As per van Steen and Tanenbaum, the most important application of virtualization is in cloud computing. Which of the following is true for Infrastructure-as-a-Service (IaaS), one of the three different services offered by cloud providers? A. IaaS providers cannot provide a service to configure a system with networked virtual servers who can communicate using IP networks. B. The isolation among customers leads to high performance C. Virtualization is key factor in IaaS, which will allow a customer to create no more than single virtual machine configured with resources D. In case of Infrastructure-as-a-Service (IaaS), virtualization allows almost complete isolation between customers of cloud providers and gives an illusion of renting a dedicated physical machine to each customer.

In case of Infrastructure-as-a-Service (IaaS), virtualization allows almost complete isolation between customers of cloud providers and gives an illusionof renting a dedicated physical machine to each customer.

According to van Steen and Tanenbaum a process is a instance of a computer program which is being executed. Which of the following statements about processes is correct? A) After a hardware interrupt, the process is shut down. B) The program counter is stored in a thread. C) One thread can consist of multiple processes. D) In order to execute a program, an OS creates virtual processors, each one for running a different program.

In order to execute a program, an OS creates virtual processors, each one for running a different program.

Which of the following is true about persistent communication? A. Persistent communication is the same as synchronous communication. B. In persistent communication, it is necessary for the sending application to continue execution after submitting the message. C. In persistent communication a message that has been submitted for transmission is stored by the communication middleware as long as it takes to deliver it to the receiver. D. In persistent communication, a receiving application must be executing when the message is submitted.

In persistent communication a message that has been submitted for transmission is stored by the communication middleware as long as it takes to deliver it to the receiver.

According to Lecture notes, which of the following statements is not TRUE. (A) In the AND model, cycle gives all the deadlocked processes. (B) In the OR model, the presence of knot indicated a deadlock. (C) Centralized deadlock detection algorithm detects phantom deadlocks. (D) Ho-Ramamoothy 1-phase algorithm doesnot detect phantom deadlock.

In the AND model, cycle gives all the deadlocked processes.

According to the textbook, which of the following is not an operation of the Message Queue Interface (MQI)? A) MQPUT B) MQOPEN C) MQGET D) MQSEND

MQOPEN

According to van Steen and Tanenbaum, which of the following is not listed as one of the three most important communication patterns in ZeroMQ? A. Pipeline B. One-Way C. Request-Reply D. Publish-Subscribe

One-way

Which of the following is true for a platform layer, one of the four layers in organization of cloud-computing? a.) This layer consists of physical components such as processors, memory and hard disk. b.) Youtube or google docs is an example of platform layer in cloud computing which allows users to upload and share videos or articles c.) It provides virtual storage and computing resources to the customers such as virtual machine for computation. d.) Platform layer provides the means to cloud-computing users to develop and execute user submitted programs. For example, software framework (Java/Python/.Net)

Platform layer provides the means to cloud-computing users to develop and execute user submitted programs. For example, software framework (Java/Python/.Net)

According to van Steen, a system's scalability can be measured along three dimensions. Which one of the following is not one of these three dimensions? A. Scalability across devices B. Geographical scalability C. Administrative scalability D. Scalability of size

Scalability across devices

According to Dr. Sudarshan Dhall'slecture on 9/17/20, which of the following types of Deadlock Models requires that a process can have at most one outstanding request for only one unit of a resource? A) Single Resource Model B) The AND Model C) The OR Model D) The Centralized Model

Single Resource Model

According to van Steen, which of the following is NOT one of the three segments of a process? A. Code segment B. Stack segment C. Resource segment D. Execution segment

Stack segment

According to van Steen, which of the following is most true concerning the election of a super peer in a peer to peer network? A. Super peers should be able to serve any number of nodes B. All normal peers should have access to a super peer, regardless of latency C.Super peers should be evenly distributed across the network D.A super peer should be created for, at most, every five nodes

Super peers should be evenly distributed across the network

According to van Steen and Tanenbaum, in an epidemic model for information dissemination, which of the following nodes has yet to see the data? A) Infected nodes B) Susceptible nodes C) Removed nodes D) Quarantined nodes

Susceptible nodes

According to Van Steen and Tanenbaum, which of the following is an example of aconnection-oriented service? A) Sending a letter B) IP C) TCP D) UDP

TCP

According to the textbook, which of the following levels in an Application Layering architecture is extremely varied between distributed systems? A. The Data Level B. The Application-Interface Level C. The Processing Level D. The User-Interface Level

The Processing Level

According to van Steen and Tanenbaum, which of thefollowing statements is true about RPCs? A. RPCs must be asynchronous if they are to be transparent to the user. B. It's important that the client and server have the same memory so that pointers work on both machines. C. The client should not be able to tell that a procedure is not implemented locally by its usage alone. D. RPCs must only send one parameter at a time.

The client should not be able to tell that a procedure is not implemented locally by its usage alone.

Considering the peer-to-peer file downloading system BitTorrent, choose the answer below that is known for high efficiency when downloading files between users. A.) Trading Phase B.) Bootstrap Phase C.) Last Download Phase D.) None of the Above

Trading Phase

Which of the following is true about user-level threads? A. In user-level threads, multiple threads are mapped to multiple schedulable entities. B. Using user-level threads makes switching thread contexts take several instructions. C. Using user-level threads makes it cheap to create and destroy threads. D. In user-level threads, the kernel is aware of threads and schedules them.

Using user-level threads makes it cheap to create and destroy threads.

Which of the following is not one of the three models discussed in section 3.1 of the book for constructing a server? A) Single-threaded process B) Multi-threading C) Variable-state machine D) Finite-state machine

Variable-state machine

According to the book in page 226, what is probabilistic flooding? A) A way to rapidly propagate information among a large collection of nodes using only local information. B) Nodes form a bridge to other remote parts of the network; therefore, they should be contacted as soon as possible. C) If node P has just been updated for data item x, it contacts an arbitrary other node Q and tries to push the update to Q. However, it is possible that Q was already updated by another node. D) When a node is flooding a message m and needs to forward m to a specific neighbor, it will do so with a probability pflood.

When a node is flooding a message m and needs to forward m to a specific neighbor, it will do so with a probability pflood.

According to Van Steen, which of the following is true about the RESTful architecture: A. RESTful services offer better solutions than traditional services. B. When distributed transactions are needed, RESTful architectures are not a good idea. C. The simplicity of RESTful architectures provides easy solutions to intricate communication schemes. D. When using RESTful calls, many syntactical errors can often be caughtduringcompile time.

When distributed transactions are needed, RESTful architectures are not a good idea.

According to Van Steen, scalability problems could be solved with scaling up. However, when it comes to scaling out, there are three basically three techniques: hiding communication latencies, distribution of work and replication. what is the advantage of Replication? A. increases availability, balance the load and hide much of the communication latency problems. B. avoid waiting for responses to remote-service requests as much as possible C. splitting data into smaller parts, and subsequently spreading those parts across the system. D. improving network with RAM, CPU,...

avoid waiting for responses to remote-service requests as much as possible