Chapter 10:Systems Development

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Objectives• Describe the systems development life cycle,

who participates in it and why it is important• Discuss systems development tools• Understand how systems development projects

are investigated

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Objectives• Describe how an existing system can be

evaluated• Discuss what is involved in planning a new

system• List the steps to implement a new or modified

system• Describe the importance of updating and

monitoring a system

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Chapter Content• An Overview of Systems Development• Tools and Techniques for Systems Development• Systems Investigation• Systems Analysis

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Chapter Content• Systems Design• Systems Implementation• Systems Maintenance and Review

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An Overview of Systems Development

• Systems development process– Includes a wide range of projects

• Purchasing a small program• Installing a huge system including hardware, software,

communications equipment, and personnel

– Typically called a systems development life cycle (SDLC)

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An Overview of Systems Development

• Systems investigation and analysis – Looks at the existing system and determines if it can and

should be improved

• Systems design and implementation– Selecting and planning the best solution– Modifying an existing system or developing a new one, placing

the best solution into effect

• Maintenance and review– Evaluating the results of the solution– Makes sure that the new or modified system is operating as

intended

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An Overview of Systems Development

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Participants in Systems Development

• System stakeholders– Individuals who will benefit from systems

development project

• Users– Individuals who will be interacting with the system on

a regular basis

• Managers– People most capable of initiating and maintaining

change

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Participants in Systems Development

• Systems development specialists– Project leader

• Individual in charge of the systems development effort

– Systems analyst• Specializes in analyzing and designing systems

– Software engineer or computer programmer• Responsible for modifying or creating programs to satisfy

user requirements

– Computer systems management• Includes the chief information officer (CIO) and other

technicians

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Participants in Systems Development

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Why Start A Systems Development Project?• Several reasons:

– Problems with existing systems– Mergers– Competition– Pressure from government agencies

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Why Start A Systems Development Project?• Creative analysis

– Investigating new approaches to existing problems

• Critical analysis– Being skeptical and doubtful– Questioning whether or not the current computer

system is still effective and efficient

• Systems development process– Begins with gathering information on users’ needs

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Systems Development Planning• System development planning

– Translation of organized or individual goals into systems development initiatives

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End-User Systems Development• End-user systems development

– Development of computer systems by individuals outside of the formal planning and departmental structure

– Range from small to significant• Software routine to merge data with form letters• Customer contact databases

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End-User Systems Development

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Tools and Techniques for Systems Development• Systems development tools

– Can greatly simplify the systems development process

– Include• Computer-aided software engineering tools (CASE)• Flowcharts, decision tables• Project management software• Prototyping• Outsourcing and object-oriented systems development

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Computer-Aided Software Engineering

• Software engineering– Employs computer-aided software engineering

(CASE) tools

• CASE tools – Automate many systems development tasks– Allow more than one person to work on the same

system at the same time via a multiuser interface

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Computer-Aided Software Engineering

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Flowcharts• Chart the path from a starting point to the final

destination• Can display various amounts of detail• When developing a system

– General flowchart describes the overall purpose and structure of the system

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Flowcharts

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Flowcharts

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Decision Tables• Can be used as an alternative to or in

conjunction with flowcharts• In general, a decision table displays

– The various conditions that could exist – The different actions that the computer should take

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Decision Tables

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Project Management Tools• Purpose is to plan, monitor, and control necessary

development activities• Program Evaluation and Review Technique (PERT)

– Creates three time estimates for an activity • The shortest possible time• The most likely time• The longest possible time

• Gantt charting– A grid that lists activities and deadlines

• Project crashing– Reducing project completion time

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Project Management Tools

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Project Management Tools

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Prototyping• The creation of a preliminary model or version of

a major subsystem• Iterative approach to systems development

– Each phase of the SDLC is repeated several times (iterated)

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Prototyping

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Outsourcing• Use of outside company to take over portions of

its workload• Challenges and disadvantages

– Internal experience and loyalty can suffer– People can lose jobs and be very emotional– Once outside company leaves, internal employees

lack experience– Difficult to compete when using the same companies

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Object-Oriented Systems Development

• An extension of object-oriented programming• Can be used during all phases of systems

development• Organizations

– Have saved time and money using the object-oriented approach to systems development

• Objects can be diagrammed– Actor and use case

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Object-Oriented Systems Development

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Systems Investigation• Overall purpose

– Determine whether objectives of existing system satisfy the goals of the organization

• Attempts to answer the following questions– What primary problems might a new or enhanced system solve?– What opportunities might a new or enhanced system provide?– What new hardware, software, databases, telecommunications,

personnel, or procedures will improve the existing system or are required for a new system?

– What are the potential costs?– What are the associated risks?

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Feasibility Analysis• Technical feasibility

– Concerned with whether or not hardware/software can be acquired or developed to solve the problem

• Economic feasibility– Determines if the project makes financial sense

• Legal feasibility– Determines whether laws or regulations may prevent

or limit a systems development project

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Feasibility Analysis• Operational feasibility

– Measure of whether or not the project can be put into action or operation

• Schedule feasibility– Determines if the project can be completed in a

reasonable amount of time

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Feasibility Analysis

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Systems Analysis• Attempts to understand how the existing system

helps solve the problem identified in systems investigation

• Overall emphasis – To gather data on the existing system and the

requirements for the new system– To consider alternative solutions to the problem and

the feasibility of the solutions

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General Analysis Considerations• Formalized analysis procedure involves

– Collecting appropriate data– Analyzing the data– Determining new system requirements and project

priorities

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Collecting Data• Purpose

– To seek additional information about problems identified during systems investigation

• Techniques– Interviews– Direct observation– Outputs– Questionnaires– Other Data Collection Methods

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Collecting Data

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Collecting Data

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Requirements Analysis• Purpose

– To determine user, stakeholder, and organizational needs

• Tools and techniques– Asking Directly– Critical Success Factors– Joint Application Development– Rapid Application Development

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Requirements Analysis

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Systems Design• Overall purpose

– To select and plan a system that meets the requirements needed to deliver the problem solution

• Results– A new or modified system

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Generating Systems Design Alternatives

• First step of design– Investigate alternatives for all components

• Request for information (RFI)– Asks a computer systems vendor to provide

information about its products or services

• Request for quotes (RFQ)– Asks a computer systems company to give prices for its

products or services

• Request for proposal (RFP)– Generated during systems development

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Generating Systems Design Alternatives

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Evaluating and Selecting a Systems Design

• Evaluate design alternatives• Select the best solution for supporting your

needs– Cost comparisons– Hardware performance– Delivery dates– Price– Storage capabilities– Training– Computer speed

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The Contract• Most vendors provide standard contracts

– Designed to protect the vendor, not the organization buying the equipment

• Organizations are creating their own contracts, clearly stating – Equipment and software specifications– Training– Installation– Maintenance

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Systems Implementation • Includes

– Hardware acquisition– Software acquisition or development– User preparation– Hiring and training of personnel– Site and data preparation– Installation, testing, startup, and user acceptance

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Acquiring Hardware• Most people and organizations acquire hardware

and computers by – Purchasing, leasing, or renting computer resources

from a computer systems vendor

• “Pay as you go computing”– Organization pays only for the computer power it

uses

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Selecting and Acquiring Software:Make, Buy, or Rent• Program development life cycle

– Program specification• Description of what the software must accomplish

– Algorithm• Step-by-step sequence of computer instructions

– Syntax errors• Errors in the use of the programming language syntax

– Logic errors• Errors in the programming logic

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Selecting and Acquiring Software:Make, Buy, or Rent• Software as a service (SaaS)

– Software resides on vendor’s server• Application service provider (ASP)

– Develops, maintains, stores software and makes it available over the Internet

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Acquiring Database and Telecommunications Systems• A database is one of the most important parts of

system development– Many projects involve a database– May require both hardware and software acquisition

• Telecommunications is one of the fastest growing business applications

– May require both hardware and software acquisition

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Acquiring Database and Telecommunications Systems

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User Preparation• Readying users and stakeholders for the new or

modified system• Can include

– Marketing– Training– Documentation– Support

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User Preparation

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Computer Systems Personnel:Hiring and Training• Depending on the size of your new system,

personnel may have to be– Trained– Hired

• Systems may need– Systems manager– Programmers– Data entry operators

• The success of any computer system depends on the way it is used by the personnel within the organization

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Site Preparation• Location of the new system needs to be

prepared• For a small system

– May mean rearranging the furniture

• Larger systems– May require special wiring and air conditioning

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Data Preparation• Converting manual files into computer files• Data conversion

– May be required to transform the existing computerized files into the proper format

• Permanent data– Must be placed on a permanent storage device

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Installation• Placing computer equipment on the site and

making it operational• For a small systems development project

– May require making room on top of a desk for a new PC– Plugging it into a wall outlet– Following the manufacturer’s instructions to turn it on

• Larger projects are usually completed by the manufacturer

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Testing• Unit testing

– Developing test data that will force the computer to execute every statement in the program

• System testing– Requires the testing of all programs together

• Volume testing – Ensures that entire system can handle a large amount

of data under normal operating conditions

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Testing• Integration testing

– Ensures that new programs can interact with other major applications

• Acceptance testing– Ensures that new or modified system is operating as

intended

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Testing

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Startup• Direct conversion

– Stopping the old system and starting the new one on a given date

• Phase-in approach– New system is slowly phased in, while old one is

slowly phased out

• Pilot startup– Running a pilot or small version of the new system

along with the old

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Startup

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User Acceptance and Documentation

• User acceptance document– Agreement signed by user that a phase of the

complete system is approved

• Documentation– Includes all materials that describe the new or

modified system

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User Acceptance and Documentation

• Systems documentation– Describes the technical aspects of the new or

modified system

• User documentation– Describes how the system can be used by

noncomputer personnel

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Systems Maintenance and Review• Final steps of systems development• Involves checking, changing, and enhancing the

system to make it serve the organization better

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Reasons for Maintenance• New requests from stakeholders, users, and

managers• Bugs or errors in the program• Technical and hardware problems• Corporate mergers and acquisitions• Governmental regulations that require changes

in programs

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Financial Implications of Maintenance

• For older programs– Cost of maintenance can be up to five times greater

than cost of development

• Average programmer– Can spend from 50% - over 75% of his/her time

maintaining programs

• Important to keep track of why systems are maintained as well as the cost of maintenance

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Financial Implications of Maintenance

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Systems Review• Final phase of the systems development life cycle

– Analyzing systems to make sure that they are operating as intended

• Two types of review procedures– Event-driven review – Time-driven review

• Continuous improvement approach– Make changes even when small problems or

opportunities arise

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Summary• Phases of the SDLC

– Investigation, analysis, design, implementation, maintenance, review

• Common system development tools and techniques – CASE tools– Flowcharts– Decision tables

• Systems investigation– First step in the development of a new or modified computer

system

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Summary• Systems analysis

– The examination of existing systems

• Systems design– Prepares detailed design needs for new system or

modifications to the existing one

• Systems implementation – Includes hardware acquisition, software acquisition or

development, and user preparation

• Systems maintenance– Involves checking, changing, and enhancing the system