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Pertemuan 08System Development: System life cycle

methodologies

Matakuliah : TI307/Sistem Informasi

Tahun : 2012

Versi : 1

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Learning Outcomes

Pada akhir pertemuan ini, diharapkan mahasiswa

akan mampu :• Mahasiswa dapat Menerangkan tahap

dalam pengembangan sisfo perusahaan (C2)

• Mahasiswa dapat Memilih metode pengembangan sisfo untuk suatu perusahaan (C4)

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Outline Materi

• The Traditional SDLC• Tahapan siklus hidup sistem• Personil yang terlibat• Manajemen siklus hidup• Keuntungan sentralisasi• Susunan manajer• Tahap pembangunan

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THE SYSTEMS DEVELOPMENT LIFE CYCLE

• The system life development cycle (SDLC) is an application of the systems approach methodology to the development of an information system

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THE TRADITIONAL SDLC• It didn’t take the first system developers

long to recognize a sequence if the project was to have the best chance of success:

• Planning• Analysis• Design• Implementation• Use

• Figure 7.4 illustrates how the life cycle phases can fit into a circular pattern over time

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Planning Phase

Benefits– Define scope of the project

– Spot potential problems

– Arrange tasks in sequence

– Provide basis for control

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Steps

1. Recognize problem (the trigger)

2. Define problem

3. Set objectives

4. Identify constraints

Recall that objectives, standards, and constraints are problem-solving elements.

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Steps (cont.)

5.Conduct feasibility study (TENLOS)– Technical– Economic return– Noneconomic return– Legal and ethical– Operational– Schedule

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Steps (cont.)

6.Prepare study project proposal– Goes to MIS steering committee

7.Approve or disapprove (go/no go)– Key questions?

1.Will the system accomplish its goals?

2.Is this the best way to go about it?

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Steps (cont.)

8.Establish a control mechanism– Think in terms of:

» 1. What» 2. Who» 3. When (Person-months versus calendar months)

– PERT and CPM network diagrams

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Define theproblem

Consult

Prepare a system study proposal

Establish a control mechanism

Approve or disapprove the study project

Recognize the problem

Set system objectives

Identify systemconstraints

The Planning PhaseMIS Steering Comm Manager Systems Analyst

1.

2.

3.

4.

5.

6.

7.

8.

Conduct a feasibility study

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Analysis Phase

Steps1.Announce

» Reasons for project» Purpose: inform and counteract fear

2.Organize project team » User(s)» Specialists» Define roles

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Analysis Phase (cont.)

3. Define information needs»Methods

Personal interview (the preferred method) Observation Record search (includes review of existing

documentation) Surveys

A project directory can be maintained as an encompassing set of documentation to describe the system

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Analysis Phase (cont.)

4. Define system performance criteria

5. Prepare design proposal

(Compare to system study proposal)

6. Approve or disapprove the design project

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Announce the system study

Organize the project team

Define information needs

Define system performance criteria

Preparedesign

proposal

Approve or disapprove the design project

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2.

3.

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The Analysis PhaseMIS Steering Committee Manager Systems Analyst

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Approve or disapprove the system implementation

Prepare the detailed design system

Identify alternate system

configurations

Evaluate system

configurations

Select the best

configuration

Prepare the implementation

proposal

1.

2.

3.

4.

5.

6.

MIS Steering Committee Manager Systems Analyst

The Design Phase

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Design Phase

1.Prepare detailed design– Structured design (top down)

» System level» Subsystem level

– Documentation tools

2. Identify alternate system configurations– Refine to a manageable set

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Design Phase (cont.)

3. Evaluate configurations

4. Select best configuration

5. Prepare implementation proposal

6. Approve or disapprove the system implementation

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Implementation Phase

Acquire and integrate the physical and conceptual resources to produce a working system

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Steps for the Implementation Phase

1. Plan implementation

2. Announce

3. Obtain hardware resources

RFP / Written Proposals

4. Obtain software resources

"Make or buy"

5. Prepare database

6. Prepare physical facilities

7. Educate participants and users

8. Prepare cutover proposal

9. Approve or disapprove cutover to new systsem

10. Cutover to new system

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Plan the implementation

Announce the implementation

Control

Cutover the new system

Obtain the hardware resources

Obtain the softwareresources

Prepare the database

Educate the participants and users

Prepare the physical facilities

Control

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The Implementation PhaseMIS Steering Committee Manager Information Specialists

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Cutover Approaches

Old System

Old System New System

Immediate cutoverPhased cutover

Parallel cutover

Pilot System

Immediate

Old SystemNew SystemPhased

New system

Old SystemParallel

Time

Pilot

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Use Phase 1.Use

2.Audit (post implementation review)» By information specialist(s)» By internal auditor (a different one from the

project team member)

3. Maintain the system» Correct errors» Keep current» Improve

4. Prepare reengineering proposal

5. Approve or disapprove reengineering7-24

The Use Phase

ControlUse thesystem

Audit thesystem

Maintain the

system

Preparere-

engineeringproposal

Approve or disapprove thereengineering proposal

MIS Steering Committee Manager Information Specialists

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3

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PROTOTYPING• A prototype is a version of a potential system

that provides the developers and potential users with an idea of how the system will function when completed

• In prototyping, a prototype is produced as quickly as possible, perhaps overnight, to obtain user feedback that will enable the prototype to be improved

• Figure 7.5 shows the four steps involved in developing an evolutionary prototype

• Figure 7.6 shows the steps involved in developing a requirements prototype

• As prototyping has proven to be one of the most successful methodologies, it would be difficult to find a development project that didn’t use it to some degree

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RAPID APPLICATION DEVELOPMENT

• Rapid Application Development (RAD), is a term coined by James Martin. It refers to a development life cycle intended to produce systems quickly without sacrificing quality

• Information engineering is the name that Martin gave to his overall approach to system development, which treats it as a firm-wide activity, while the term enterprise is used to describe the entire firm

• Figure 7.7 illustrates the top-down nature of information engineering, involving both data (the left face of the pyramid) and activities (the right face)

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RAD (cont.)

• RAD requires four essential ingredients:

• Management • People • Methodologies • Tools

• Of all the components of information engineering, RAD has probably enjoyed the greatest support

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PHASED DEVELOPMENT• This is an approach for developing information

systems that consists of six stages: 1. Preliminary investigation2. Analysis 3. Design 4. Preliminary construction5. Final construction6. System test and installation

• The analysis, design, and preliminary construction stages are taken for each system module

• The six phased development stages are illustrated in Figure 7.8

• Figure 7.9 illustrates how the module phases are integrated into the system development

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PROJECT MANAGEMENT

• Today, it is possible for life cycle management to span several organizational levels and involve managers outside of IT

• Figure 7.16 shows the hierarchical nature of project management

• In this example, there are five development projects going at the same time, all managed by the MIS steering committee

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The MIS Steering Committee • The MIS Steering Committee

performs three main functions:– It establishes policies that ensure

computer support for achieving the strategic objectives of the firm

– It provides fiscal control by serving as the approval authority for all requests for computer-related funds

– It resolves conflicts that arise concerning priorities for computer use

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Project Leadership • A project team includes all of the

persons who participate in the development of an information system

• A team might have as many as a dozen members, consisting of some combination of users, information specialists, and may include an internal auditor

• A team or project leader, who provides direction throughout the life of the project, directs the team activity

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The Project Management Mechanism

• The basis for project management is the project plan

• A popular format for a detailed plan is a Gantt chart, which identifies the tasks, who will perform them, and when they will be performed

• A Gantt chart is a horizontal bar chart that includes a bar for each task to be performed arranged in a time sequence

• Figure 7.17 is the first part of a Gantt chart, prepared using a Microsoft Excel spreadsheet

• A complement to the Gantt chart is the network diagram. Figure 7.18 is a high-level network diagram that identifies the phases of a project

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End of Session 8