Distributed Software Engineering

Question 1

(MP)*Browsing the Web is the most common example of a situation where this architecture is used

Answer 1

two-tier client/server (C/S) architecture with thin clients

Question 2

(MP) Commonly used to “modernize” legacy systems when separating application processing and data management is impractical

Answer 2

two-tier client/server (C/S) architecture with thin clients

Question 3

(MP)*Applications with relatively stable end-user functionality used in an environment with well-established system management

Answer 3

two-tier client/server (C/S) architecture with fat clients

Question 4

(MP)*An example of this type of architecture is a banking ATM system for which the hardware in the teller machine carries out most of the customer-related processing associated with transactions

Answer 4

two-tier client/server (C/S) architecture with fat clients

Question 5

(MP)architecture with a bank ATM system which delivers cash and other banking services to users.

Answer 5

two-tier client/server (C/S) architecture with fat clients

Question 6

(MP)Suitable for mobile applications where Internet connectivity cannot be guaranteed

Answer 6

two-tier client/server (C/S) architecture with fat clients

Question 7

(MP)*architecture with a scalable Internet banking system

Answer 7

multi-tier client/server (C/S) architecture

Question 8

(MP)An example of this type of C/S architecture is an Internet banking system in which the bank’s customer database supports database processing, a web server provides the application services and data management, and the user’s computer supports an Internet browser

Answer 8

multi-tier client/server (C/S) architecture

Question 9

(MP)Suitable for applications where both the data and the application are volatile, and for applications where data from multiple sources are integrated.

Answer 9

multi-tier client/server (C/S) architecture

Question 10

(MP)*example of this architecture might be an easily extendable data mining system comprised of multiple standard data sources, a number of independent data “integrators” each attempting to deduce different relationships, graphical relationship “visualizers” and report generators

Answer 10

distributed component architecture

Question 11

(MP)architecture with a data mining system that looks for relationships between the data stored in a number of databases

Answer 11

distributed component architecture

Question 12

(MP)Some argue that this is less intuitive/natural than a client/server architecture, making systems more difficult to visualize, understand, and design

Answer 12

distributed component architecture

Question 13

(MP)All components are objects that provide services to, and receive services from, other objects; communication is via middleware.

Answer 13

distributed component architecture

Question 14

(MP)Objects provide general services that may be called on by other objects. This approach may be used for implementing client-server systems

Answer 14

distributed component architecture

Question 15

(MP)*This architecture has the advantage of being highly redundant and therefore both fault-tolerant and tolerant of nodes disconnecting from the network

Answer 15

peer-to-peer architecture (P2P)

Question 16

(MP)Examples of systems employing this architecture include Freenet, ICQ, and Jabber.

Answer 16

peer-to-peer architecture (P2P)

Question 17

(MP)*Appropriate where the system primarily involves the exchange of information between individual computers on a network and there is no need for this information to be centrally stored or managed (e.g., file-sharing systems)

Answer 17

peer-to-peer architecture (P2P)

Question 18

(MP)*Appropriate for computationally intensive applications for which it is possible to separate the processing required into a large number of independent computations

Answer 18

peer-to-peer architecture (P2P)

Question 19

(MP)*examples include web-based mail systems such as Yahoo! and Gmail, and office application such as Google docs

Answer 19

software as a service (SaaS)

Question 20

(MP)*Provides functionality on a remote server with client access through a web browser. The server maintains the user’s data and state during an interaction session. Transactions are usually long (e.g., editing a document)

Answer 20

software as a service (SaaS)

Question 21

(MP)Software delivery method whereby a software system is hosted remotely on a provider’s server (a “cloud”)

Answer 21

software as a service (SaaS)

Question 22

(MP)*An approach to structuring a software system as a set of separate, stateless services that may entail multiple providers and may be distributed.

Answer 22

service-oriented architecture (SOA)

Question 23

(MP)*Some developers of systems based on this architecture have opted to replace existing “inefficient” protocols developed to be open standards with so-called RESTful protocols having inherently lower overhead

Answer 23

service-oriented architecture (SOA)

Question 24

(MP)A strategy for designing and building software products through the composition of existing capabilities and services

Answer 24

service-oriented architecture (SOA)

Question 25

(MP)Structures a system as a set of separate, stateless services that may be provided by multiple providers and distributed. Typically, transactions are short, whereby a service is called, does something, and then returns a result

Answer 25

service-oriented architecture (SOA)

Question 26

(MP)**Commonly used in real-time systems where there may be separate processors associated with data acquisition from the system’s environment, data processing, and computation and actuator management.

Answer 26

master-slave architecture

Question 27

(MP)*architecture with a real-time traffic control system that has three logical processes that run on separate processors

Answer 27

master-slave architecture

Question 28

(12-SC) which one of the following is “the most important development that has affected distributed software systems in the past few years”?

Answer 28

The service-oriented approach

Other Wrong:

• The CORBA middleware standard.
• The message-based (non-synchronous) distributed component interaction model
• Client-server computing.
• Peer-to-peer technologies

Question 29

(QA)Briefly describe the scalability issue, and explain the distinction between “scaling-up” and “scaling-out” in addressing this issue

Answer 29

How can a system be constructed so as to deliver a high quality service (QoS) as demands on the system increase? Systems can be designed to “scale-up” by replacing resources with more powerful ones, and/or “scale-out” by adding additional resources

Question 30

Briefly describe the transparency issue

Answer 30

Should the distributed system in question appear to the user as a single (i.e., not a distributed) system, or would it be better for users to understand that the system is, in fact, distributed so they can better cope with problems that may arise?

Question 31

Briefly describe the openness issue

Answer 31

Should the system in question be designed using standard, generally accepted protocols that would support the integration of components from many suppliers that can interoperate with other system components, or should more specialized (possibly more efficient, more secure, etc.) protocols be used that would restrict the designer’s freedom in this regard?

Question 32

(11-QA) One of the factors that may need to be considered when implementing SaaS is multi-tenancy. From the users’ perspective, what are the two basic goals or objectives associated with multi-tenancy?

Answer 32

Giving each user the impression of being the sole system user, and allowing the efficient sharing of the system’s resources

Question 33

**(11-QA) **One of the factors that may need to be considered when implementing SaaS is multi-tenancy. From a designer’s perspective, what is required in order to achieve these goals/objectives?

Answer 33

The system must be designed so that there is an absolute separation between the system functionality and the system state. (Thus, all operations should be “stateless”.)

Question 34

(QA)Briefly describe Security

Answer 34

How can usable security policies be defined and implemented that apply across a set of independently managed systems?

Question 35

(QA)Briefly describe QOS

Answer 35

How should the QOS delivered to system users be specified and how should system be implemented to deliver an acceptable QOS to all users?

Question 36

(QA)Briefly describe Failure Mangement

Answer 36

How can system failures be detected, contained, and repaired?