Chapter 13 Flashcards
(185 cards)
1
Q
organizations must analyze the need for applications and then _________
A
justify each purchase in terms of costs and benefits.
2
Q
need for information systems is usually related to __________ and __________
A
organizational planning and to the analysis of its performance vis-à-vis its competitors
3
Q
What must the cost-benefit justification consider?
A
he wisdom of investing in a specific IT application versus spending the funds on alternative projects
4
Q
def. application portfolio
A
The set of recommended applications resulting from the planning and justification process in application development
5
Q
What does the planning process for new IT applications begin with?
A
an analysis of the organizational strategic plan
6
Q
what does the organization’s strategic plan do?
A
identifies the firm’s overall mission, the goals that follow from that mission, and the broad steps required to reach these goals
7
Q
what does the strategic planning process do?
A
modifies the organization’s objectives and resources to match its changing markets and opportunities
8
Q
What provides the inputs in developing the IT strategic plan?
A
organizational strategic plan and the existing IT architecture
9
Q
what does the IT architecture do? What does it encompass?
A
- delineates the way an organization should utilize its information resources to accomplish its mission
- encompasses both the technical and the managerial aspects of information resources
10
Q
what does the technical aspects of IT structure include?
A
hardware and operating systems, networking, data management systems, and applications software.
11
Q
what do the managerial aspects of IT architecture do?
A
specify:
- how the IT department will be managed,
- how the functional area managers will be involved,
- how IT decisions will be made.
12
Q
def. IT strategic plan
A
A set of long-range goals that describe the IT infrastructure and major IT initiatives needed to achieve the goals of the organization
13
Q
What three objectives must the IT strategic plan meet?
A
- It must be aligned with the organization’s strategic plan.
- -critical because org’s ISs must support the organization’s strategies - It must provide for an IT architecture that seamlessly networks users, applications, and databases.
- It must efficiently allocate IS development resources among competing projects so that the projects can be completed on time and within budget and still have the required functionality.
14
Q
why is the existing architecture a necessary input into the IT strategic plan?
A
acts as a constraint on future development efforts
-not an absolute constraint
15
Q
what is a critical component in developing and implementing the IT strategic plan?
A
IT steering committee
16
Q
def. IT steering committee
A
committee, composed of a group of managers and staff representing various organizational units, set up to establish IT priorities and to ensure that the MIS function is meeting the needs of the enterprise.
17
Q
why is th IT steering committee important to you?
A
because it ensures that you get the information systems and applications that you need to do your job
18
Q
what happens after a company has agreed on an IT strategic plan?
A
develops IS operational plan
19
Q
def. IS operational plan
A
A clear set of projects that the IS department and the functional area managers will execute in support of the IT strategic plan.
20
Q
Describe the elements of a typical IS operational plan? (6)
A
- Mission: The mission of the IS function (derived from the IT strategy).
- IS environment: A summary of the information needs of the individual functional areas and of the organization as a whole.
- Objectives of the IS function: The best current estimate of the goals of the IS function.
- Constraints on the IS function: Technological, financial, personnel, and other resource limitations on the IS function.
- The application portfolio: A prioritized inventory of present applications and a detailed plan of projects to be developed or continued during the current year.
- Resource allocation and project management: A listing of who is going to do what, how, and when.
21
Q
What is the first step in the acquisition process? Why?
A
Developing an IT plan
-Because all companies have limited resources, they must justify investing resources in some areas, including IT, rather than in others
22
Q
What does justifying IT investment involve?
A
calculating the costs, assessing the benefits (values), and comparing the two
ie. Cost-benefit analysis
23
Q
Wha is one of the major challenges companies face regarding IT and costs?
A
allocate fixed costs among different IT projects
24
Q
def. fixed costs
A
costs that remain the same regardless of any change in the company’s activity level.
25
what are some IT fixed costs?
infrastructure costs and the costs associated with IT services and IT management
26
what is another complication regarding IT and costs? Why is it critical?
the costs of a system do not end when the system is installed. Rather, costs for maintaining, debugging, and improving the system can accumulate over many years
-a critical point because organizations sometimes fail to anticipate these costs when they make the investment.
27
T or F: evaluating the benefits of IT projects is more complex than calculating their costs
true
28
Why are benefits more difficult to evaluate than costs?
- Benefits may be more difficult to quantify, especially because many of them are intangible
- organizations use IT for multiple purposes further complicates benefit analysis.
- to obtain a return from an IT investment, the company must implement the technology successfully, many aren't
- the proposed system may be “cutting edge.” In these cases, there may be no precedent for identifying the types of financial payback the company can expect
29
What do some companies do to test their tech?
may actually implement the technology at one or more locations to verify that the technology functions effectively and is accepted by consumers
30
T or F: there is a uniform strategy to conduct cost-benefit analyses
False
31
What are the four common approaches to conducting a cost-benefit analysis?
(1) net present value, (2) return on investment, (3) break-even analysis, and (4) the business case approach.
32
Describe the net present value method
- use the net present value (NPV) method to convert future values of benefits to their present-value equivalent by “discounting” them at the organization's cost of funds.
- They can then compare the present value of the future benefits with the cost required to achieve those benefits to determine whether the benefits exceed the costs.
33
describe the return on investment (ROI) method
- measures management's effectiveness in generating profits with its available assets.
- ROI is calculated by dividing the net income generated by a project by the average assets invested in the project.
- ROI is a percentage, and the higher the percentage return, the better.
34
describe break-even analysis
the point at which the cumulative dollar value of the benefits from a project equals the investment made in the project.
35
describe business case approach
- system developers write a business case to justify funding one or more specific applications or projects.
- IS professionals will be a major source of input when business cases are developed because these cases describe what you do, how you do it, and how a new system could better support you.
36
What are the fundamental decisions a company has to make when deciding how to pursue an IT investment? (4)
* How much computer code does the company want to write?
* How will the company pay for the application?
* Where will the application run?
* Where will the application originate?
37
Describe the decision "How much computer code does the company want to write? "
A company can choose to use a totally prewritten application (write no computer code), to customize a prewritten application (write some computer code), or to custom-write an entire application (write all new computer code).
38
Describe the decision "How will the company pay for the application?"
Once the company has decided how much computer code to write, it must decide how to pay for it. With prewritten applications or customized prewritten applications, companies can buy them or lease them. With totally custom applications, companies use internal funding.
39
describe the decision "Where will the application run?"
The next decision is whether to run the application on the company's platform or on someone else's platform. In other words, the company can employ either a software-as-a-service vendor or an application service provider.
40
describe the decision "where will the application originate?"
Prewritten applications can be open-source software or they can come from a vendor. The company may choose to customize prewritten open-source applications or prewritten proprietary applications from vendors. Further, it may customize applications in-house, or it can outsource the customization. Finally, it can write totally custom applications in-house, or it can outsource this process.
41
What is a good rule of thumb regarding acquisition methods?
an organization should consider all feasible acquisition methods in light of its business requirements
42
Advantages of Buying Software (purchasing a prewritten application)
* Many different types of off-the-shelf software are available.
* The company can try out the software before purchasing it.
* The company can save much time by buying rather than building.
* The company can know what it is getting before it invests in the product.
* Purchased software may eliminate the need to hire personnel specifically dedicated to a project.
43
Disadvantages of purchasing a prewritten application?
* Software may not exactly meet the company's needs.
* Software may be difficult or impossible to modify, or it may require huge business process changes to implement.
* The company will not have control over software improvements and new versions.
* Purchased software can be difficult to integrate with existing systems.
* Vendors may discontinue a product or go out of business.
* Software is controlled by another company with its own priorities and business considerations.
* The purchasing company lacks intimate knowledge about how and why the software functions as it does.
44
When is customizing a prewritten application especially attractive?
if the software vendor allows the company to modify the application to meet its needs
45
when is customization not attractive?
- in cases where customization is the only method of providing the necessary flexibility to address the company's needs
- not the best strategy when the software is either very expensive or likely to become obsolete in a short time
46
what is a challenge for customization?
customizing a prewritten application can be extremely difficult, particularly for large, complex applications.
47
What can the lease option do compared to customizing and buying
can save a company both time and money
48
what is a challenge with leased applications?
may not exactly fit the company's application requirement
49
What does vendor software that can be leased generally include?
the features that are most commonly needed by organizations in a given industry
50
What rule do interested companies apply when they evaluate vendor software?
80/20 rule
if the software meets 80 percent of the company's needs, then the company should seriously consider modifying its business processes so that it can utilize the remaining 20 percent
**Many times this is a better long-term solution than modifying the vendor software. Otherwise, the company will have to customize the software every time the vendor releases an updated version.
51
Who is leasing attractive to?
small and medium-sized enterprises that cannot afford major investments in IT software.
- large companies who want to test potential IT solutions before committing to major investments
- a company that does not employ sufficient IT personnel with the appropriate skills for developing custom IT applications may choose to lease software instead of developing it in-house
- companies who want to establish a quicker presence in the market
52
What three ways can leasing be executed?
1. to lease the application from a software developer, install it, and run it on the company's platform.
- --The vendor can assist with the installation and frequently will offer to contract for the support and maintenance of the system. Many conventional applications are leased this way.
2. leasing an application and running it on the vendor's platform, using an application service provider to accomplish this
3. leasing an application and running it on the vendor's platform., using a software-as-a-service vendor to accomplish this
53
def. application service provider
An agent or vendor that assembles the software needed by enterprises and packages them with outsourced development, operations, maintenance, and other services
54
how does the customer access applications with an application service provider
through the internet
55
ASP host both a/an ___________ and a/an _________ for each customer
an application and a database for each customer.
56
def. Software-as-a-service
A method of delivering software in which a vendor hosts the applications and provides them as a service to customers over a network, typically the Internet
57
What does SaaS eliminate the need for? What does this do?
eliminates the need for customers to install and run the application on their own computers
-save the expense (money, time, IT staff) of buying, operating, and maintaining the software
58
with SaaS, the vendor hosts what? (2 big things)
- an application that multiple customers can use
| - a database that is partitioned for each customer to protect the privacy and security of each customer's data
59
For prewritten applications companies can use, companies can use _____________
can use open-source software or obtain the software from a vendor
60
For customized prewritten applications, they can __________
customize open-source software or customize vendor software
61
for totally custom applications, they can ___________
write the software in-house or they can outsource the process
62
With open source software organizations obtain a licence to do what?
to implement an open-source software product and either use it as is, customize it, or develop applications with it.
63
Unless the company is one of the few that want to tinker their source code, open-source applications are ______________
basically, the same as a proprietary application except for licensing, payment, and support.
64
open-source software is really an __________ rather than a conceptually different development option
alternative source of applications
65
def. outsourcing
The use of outside contractors or external organizations to acquire IT services
66
What are some reasons companies use outsourcing?
- they might want to experiment with new IT technologies without making a substantial upfront investment
- to obtain access to outside experts
67
what is a disdavantage of outsourcing?
companies frequently must place their valuable corporate data under the control of the outsourcing vendor
68
What are some main general characteristics that companies can offer?
offer a range of outsourcing services for developing, operating, and maintaining IT applications
69
What can offshoring do? (positive)
save money
70
What are is a risk of offshoring?
- If a company is offshoring application development, then the major risk is poor communication between users and developers
71
what does continuous application development do?
automates and improves the process of software delivery
72
T or F: a software development project is viewed as having a defined product, with development stopped when the product is implemented
False
a software development project is viewed as constantly changing in response to changing business conditions and in response to user acceptance.
73
def. continuous application development
The process of steadily adding new computer code to a software project when the new computer code is ready
- Each development team member submits new code when it is finished.
- Automated testing is performed on the code to ensure that it functions within the software project requirements.
74
What does continuous code submission provide?
developers with immediate feedback from users and status updates for the software on which they are working
75
how can companies custom-build an application?
can either perform this operation in-house or outsource the process
76
Summarize the main pros/cons of custom development
custom development is usually more time consuming and costly than buying or leasing, it often produces a better fit with the organization's specific requirements
77
When does the development process start?
when the IT steering committee , having received suggestions for a new system, decides it is worth exploring
-These suggestions come from users
Understanding this process will help you obtain the systems that you need. Conversely, not understanding this process will reduce your chances, because other people who understand it better will make suggestions that use up available resources.
78
What happens as the company goes through the development process?
its mindset changes
79
What happens in the systems investigation?
the organization is trying to decide whether to build something. Everyone knows it may or may not be built
80
In the later stages of the development process, what does the organization do?
the organization is committed to building the application.
81
What is the basic, backbone methodology for custom development? What is it used for?
systems development life cycle (SDLC)
-typically used for large-scale information systems development projects. However, entrepreneurs are also using custom development to deploy much smaller information systems such as mobile apps
82
What are the six typical processes in the systems development life cycle?
* Systems investigation
* Systems analysis
* Systems design
* Programming and testing
* Implementation
* Operation and maintenance
83
def. systems development life cycle (SDLC)
The traditional structured framework, used for large IT projects, that consists of sequential processes by which information systems are developed
84
What is the deliverable during the systems investigation process?
go/no-go decision
85
What is the deliverable during the systems analysis process?
user requirements
86
What is the deliverable during the systems design process?
technical specifications
87
What happens when problems occur during any phase of the SDLC?
developers must go back to previous phases
88
how do systems development projects produce desired results?
through team efforts
| development teams
89
What do development teams typically include?
users, systems analysts, programmers, and technical specialists
90
who are users?
employees from all functional areas and levels of the organization who interact with the system, either directly or indirectly
91
def. systems analysts
IS professionals who specialize in analyzing and designing information systems
92
def. programmers
IS professionals who modify existing computer programs or write new computer programs to satisfy user requirements
93
def. technical specialists
Experts in a certain type of technology, such as databases or telecommunications
94
def. systems stakeholders
All people who are affected by changes in information systems
-All stakeholders are typically involved in systems development at various times and in varying degrees.
95
Describe user involvement over the stages of SDLC
users have high involvement in the early stages of the SDLC, lower involvement in the programming and testing stage, and high involvement in the later stages
96
Advantages of TRADITIONAL SYSTEMS DEVELOPMENT (SDLC)
* Forces staff to systematically go through every step in a structured process.
* Enforces quality by maintaining standards.
* Has lower probability of missing important issues in collecting user requirements.
97
disadvantages of TRADITIONAL SYSTEMS DEVELOPMENT (SDLC)
* May produce excessive documentation.
* Users may be unwilling or unable to study the approved specifications.
* Takes too long to progress from the original ideas to a working system.
* Users have trouble describing requirements for a proposed system.
98
advantages of Prototyping
* Helps clarify user requirements.
* Helps verify the feasibility of the design.
* Promotes genuine user participation.
* Promotes close working relationship between systems developers and users.
* Works well for ill-defined problems.
* May produce part of the final system.
99
disadvantages of prototyping
* May encourage inadequate problem analysis.
* Is not practical with a large number of users.
* User may not want to give up the prototype when the system is completed.
* May generate confusion about whether the system is complete and maintainable.
* System may be built quickly, which can result in lower quality.
100
Advantages of joint application design (JAD)
* Involves many users in the development process.
* Saves time.
* Generates greater user support for the new system.
* Improves the quality of the new system.
* The new system is easier to implement.
* The new system has lower training costs.
101
disadvantages of joint application design (JAD)
* It is difficult to get all users to attend the JAD meetings.
* The JAD approach is subject to all of the problems associated with any group meeting.
102
advantages of INTEGRATED COMPUTER-AIDED SOFTWARE ENGINEERING
* Can produce systems with a longer effective operational life.
* Can produce systems that closely meet user requirements.
* Can speed up the development process.
* Can produce systems that are more flexible and adaptable to changing business conditions.
* Can produce excellent documentation.
103
disadvantages of INTEGRATED COMPUTER-AIDED SOFTWARE ENGINEERING
* Systems are often more expensive to build and maintain.
* The process requires more extensive and accurate definition of user requirements.
* It is difficult to customize the end product.
104
advantages of rapid application development
* Can speed up systems development.
* Users are intensively involved from the start.
* Improves the process of rewriting legacy applications.
105
disadvantages of rapid application development
•Produces functional components of final systems, but not the final systems themselves.
106
advantages of end-user development
* Bypasses the IS department and avoids delays.
* User controls the application and can change it as needed.
* Directly meets user requirements.
* Promotes increased user acceptance of new system.
* Frees up IT resources.
107
disadvantages of end-user development
* May eventually require maintenance from IS department.
* Documentation may be inadequate.
* Leads to poor quality control.
* System may not have adequate interfaces to existing systems.
* May create lower quality systems.
108
advantages of object-oriented development
* Objects model real-world entities.
| * New systems may be able to reuse some computer code.
109
disadvantages of object-oriented development
•Works best with systems of more limited scope (i.e., with systems that do not have huge numbers of objects).
110
What three things cause greater chances of success?
Systems development professionals agree that the more time they invest in (1) understanding the business problem to be solved, (2) specifying the technical options for the systems, and (3) anticipating the problems they are likely to encounter during development, the greater the chances of success
111
def. systems investigation
The initial stage in the traditional systems development life cycle that addresses the business problem (or business opportunity) by means of the feasibility study.
112
What is the primary task in the systems investigation stage?
the feasibility study
113
def. feasibility study
An investigation that gauges the probability of success of a proposed project and provides a rough assessment of the project's feasibility
114
What are the three basic solutions to any business problem relating to an IS?
(1) do nothing and continue to use the existing system unchanged, (2) modify or enhance the existing system, and (3) develop a new system.
115
what does the feasibility study do with regards to the three basic solutions?
analyzes which of these three solutions best fits the particular business problem. It also provides a rough assessment of the project's technical, economic, and behavioural feasibility
116
def. technical feasibility
- determines whether the company can develop and/or acquire the hardware, software, and communications components needed to solve the business problem
- also determines whether the organization can use its existing technology to achieve the project's performance objectives.
117
def. economic feasibility
- determines whether the project is an acceptable financial risk and, if so, whether the organization has the necessary time and money to successfully complete the project
- techniques/commonly used methods: NPV, ROI, break-even analysis, and the business case approach.
118
def. behavioural feasibility
addresses the human issues of the systems development project.
--You will be heavily involved in this aspect of the feasibility study.
119
What happens in the systems investigation stage after the feasibility analysis?
-a “go/no-go” decision is reached by the steering committee if there is one or by top management in the absence of a committee
120
What does the go/no-go decison depend on
go/no-go decision does not depend solely on the feasibility analysis. Organizations often have more feasible projects than they can fund. Therefore, the firm must prioritize the feasible projects and pursue those with the highest priority.
121
Are unfunded feasible projects always presented to the IT department?
No
Unfunded feasible projects may not be presented to the IT department at all. These projects therefore contribute to the hidden backlog, which are projects that the IT department is not aware of.
122
If the decision is a no-go, then what happens?
then the project either is put on the shelf until conditions are more favourable or it is discarded
123
if the decision is a go, then what happens
then the project proceeds, and the systems analysis phase begin
124
def. systems analysis
The examination of the business problem that the organization plans to solve with an information system
125
What is the primary purpose of the systems analysis stage?
to gather information about the existing system to determine the requirements for an enhanced system or a new system.
The end product of this stage, known as a deliverable, is a set of system requirements.
126
What is the most difficult task in the systems analysis stage?
to identify the specific requirements that the system must satisfy.
These requirements are often called user requirements, because users (meaning you) provide them. When the systems developers have accumulated the user requirements for the new system, they proceed to the systems design stage.
127
def. systems design
The way in which a new system will resolve a business problem.
128
What do technical system specifications specify?
* System outputs, inputs, calculations or processing, and user interfaces.
* Hardware, software, databases, telecommunications, personnel, and procedures.
* A blueprint of how these components are integrated.
129
what happens when the system specifications are approved by all participants?
They are “frozen.” That is, they should not be changed
130
What happens if you add functions after the project has been initiated
causes scope creep, in which the time frame and expenses associated with the project expand beyond the agreed-upon limits
131
def. scope creep
the addition of functions to an information system after the project has begun.
132
what does scope creep endanger
project's budget and its schedule
133
What do successful project managers do to prevent scope creep and why?
successful project managers place controls on changes requested by users
Because scope creep is expensive
134
def. programming
The translation of a system's design specifications into computer code
135
why can programming be lengthy/time consuming
because writing computer code is as much an art as a science
136
what does testing in the programming stage do?
Testing is the process that assesses whether the computer code will produce the expected and desired results. It is also intended to detect errors, or bugs, in the computer code
137
def. implementation (or deployment)
The process of converting from an old computer system to a new one
138
what does the conversion process during implementation involve?
organizational change
Both end users and the MIS department need to work together to manage organizational change
139
what are the three major conversion strategies?
direct, pilot, phased
140
def. direct conversion
A systems implementation process in which the old system is cut off and the new system is turned on at a certain point in time
- least expensive
- most risky because, if the new system does not work as planned, there is no support from the old system.
- most systems are implemented using direct conversion
141
def. pilot conversion
A systems implementation process that introduces the new system in one part of the organization on a trial basis; when the new system is working properly, it is introduced in other parts of the organization
142
def. phased conversion
A systems implementation process that introduces components of the new system in stages, until the entire new system is operational
143
what types of conversion do large organizations commonly use?
combine the pilot and phased approaches. That is, they execute a phased conversion using a pilot group for each phase
144
what is a fourth strategy of conversion?
parallel conversion
in which the old and new systems operate simultaneously for a time
rarely used today because it's completely impractical
145
what is used instead of a typical parallel conversion?
a “historic parallel,” is used in which real transactions are run through the new system and the results compared with the old system before the new systems are moved in for live usage.
146
What types of maintenance might a system require?
1. debugging the program, a process that continues throughout the life of the system.
2. updating the system to accommodate changes in business condition
3. adds new functions to the existing system without disturbing its operation.
147
def. joint application design
a group-based tool for collecting user requirements and creating system designs
148
where is joint application design most often used?
within the systems analysis and systems design stages of the SDLC
149
what does JAD involve?
a group meeting attended by the analysts and all of the users that can be conducted either in person or via the computer
During this meeting, all users jointly define and agree on the systems requirements. This process saves a tremendous amount of time
150
def. rapid application development (RAD)
A systems development method that uses special tools and an iterative approach to rapidly produce a high-quality system
-can combine JAD, prototyping, and integrated computer-aided software engineering (ICASE) tools to rapidly-produce a high-quality system
151
in the first RAD stage, what happens?
developers use JAD sessions to collect system requirements. This strategy ensures that users are intensively involved early on.
152
what does it mean that RAD is iterative?
requirements, designs, and the system itself are developed and then undergo a series, or sequence, of improvements
153
what does RAD use to quickly structure requirements and develop prototypes?
ICASE tools
154
as the prototypes are developed and refined during RAD, what happens?
users review them in additional JAD sessions
155
what does RAD produce?
produces the functional components of a final system, rather than prototypes
156
def. agile development
A software development methodology that delivers functionality in rapid iterations, measured in weeks, requiring frequent communication, development, testing, and deliver
157
what does agile development require to be successful?
frequent communication, development, testing, and delivery.
158
what does agile development focus on?
rapid development and frequent user contact to create software that addresses the needs of business users
159
does agile development software have to include every possible feature the user will require?
No
Rather, it must meet only the user's more important and immediate needs. It can be updated later to introduce additional functions as they become necessary
160
what is the core tenet of agile development?
to do only what you have to do to be successful right now.
161
what is a key principle of the scrum approach?
during a project, users can change their minds about what they want and need
162
what does scrum acknowledge?
that a development problem cannot be fully understood or defined from the start.
163
what does scrum focus on?
focuses on maximizing the development team's ability to deliver iterations quickly and to respond effectively to additional user requirements as they emerge
164
What are scrum's primary roles?
* The Scrum Master: Maintains the processes (typically replaces a project manager).
* The Product Owner: Represents the business users and any other stakeholders in the project.
* The Team: A cross-functional group of about seven people who perform the actual analysis, design, coding, implementation, testing, and so on.
165
How does scrum work?
- During each sprint—typically a two- to four-week period—the team creates a potentially shippable product increment, such as working and tested software.
- The set of features that goes into each sprint comes from the product backlog, which is a prioritized set of high-level work requirements to be completed.
- The sprint planning meeting determines which backlog items will be addressed during a sprint.
- During this meeting, the Product Owner informs the team of the items in the product backlog that he or she wants to be completed.
- The team members then determine how many of these projects they can commit to during the next sprint, and they record this information in the sprint backlog.
166
During a sprint, are people allowed to change the sprint backlog?
No, requirements are frozen for the sprint
167
Does each sprint have to end on time?
yes
168
What happens if requirements are not completed (sprints)?
then they are left out and returned to the product backlog. After each sprint is completed, the team demonstrates how to use the software.
169
def. end-user development
A software development approach in which the organization's end users develop their own applications with little or no formal assistance from the IT department
170
def, prototyping
An approach to systems development that defines an initial list of user requirements, builds a prototype system, and then improves the system in several iterations based on users' feedback
-Developers do not try to obtain a complete set of user specifications for the system at the outset, and they do not plan to develop the system all at once
171
prototype
A small-scale working model of an entire system or a model that contains only the components of the new system that are of most interest to the users
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How do prototypes work?
Users make suggestions for improving the prototype, based on their experiences with it. The developers then review the prototype with the users and implement some of their suggestions to refine it. This process continues through several iterations until the users approve the system or it becomes apparent that the system cannot meet the users' needs. If the system is viable, then the developers can use the prototype to build the full system.
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what is a practical problem with prototyping?
that a prototype usually looks more complete than it is. That is, it may not use the real database, it usually does not have the necessary error checking, and it almost never includes the necessary security features. Users who review a prototype that resembles the finished system may not recognize these problems. Consequently, they might have unrealistic expectations about how close the actual system is to completion.
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def. computer-aided software engineering (CASE)
A software development approach that uses specialized tools to automate many of the tasks in the systems development life cycle; upper CASE tools automate the early stages of the life cycle and lower CASE tools automate the later stages
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def. upper CASE tools
Tools that are used to automate the early stages of the systems development life cycle (systems investigation, analysis, and design).
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def. lower CASE tools
Tools used to automate later stages in the systems development life cycle (programming, testing, operation, and maintenance).
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def. integrated CASE (ICASE) tools
CASE tools that provide links between upper CASE and lower CASE tools
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def. component-based development
A software development methodology that uses standard components to build applications
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what are components?
reusable applications that generally have one specific function, such as a shopping cart, user authentication, or a catalogue.
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describe component based development compared to other approaches
generally involves less programming and more assembly
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what is Component-based development closely linked with?
the idea of web services and service-oriented architectures
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def. object-oriented development
A systems development methodology that begins with aspects of the real world that must be modelled to perform a task (rather than beginning with the task)
beginning with real world aspects allows it to be applied to other situations
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what does the development process for an object-oriented system begin with?
a feasibility study and an analysis of the existing system
Systems developers identify the objects in the new system—the fundamental elements in OO analysis and design. Each object represents a tangible, real-world entity, such as a customer, bank account, student, or course. Objects have properties, or data value
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in addition to properties or data claues, what do objects contain?
the operations that can be performed on their properties
Operations are also referred to as behaviours.
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what does the obkect approach enable OO analysts to do?
- to define all the relevant objects needed for the new system, including their properties and operations.
- The analysts then model how the objects interact to meet the objectives of the new system.
- In some cases, analysts can reuse existing objects from other applications (or from a library of objects) in the new system
- saves the analysts the time they otherwise would spend coding these objects. In most cases, however, even with object reuse, some coding will be necessary to customize the objects and their interactions for the new system.
