MIS400 1

MIS360

Foundations for Systems Development

Chapter 1: The Systems Development Environment

Learning Objectives

 Define information systems analysis and design.

 Describe the role of the systems analyst in information systems development.

 Describe the information systems development life cycle (SDLC).

 List alternatives to the systems development life cycle.

Chapter Preview

 Systems Analysis is a proven method to help a business utilize information to its fullest capacity

 Systems Development Life Cycle (SDLC)  Central to Information Systems Development

Chapter Preview

• Information technology (IT) can mean the difference between success and failure for any organization.

• IT is a Combination of hardware and software products and services that companies use to manage, access, communicate, and share information

Refresh our memory from MIS300:

• What is a System? • Means: process of taking an input and producing an

output.

• System is anything that takes an input and generates an output. It is not exclusive to computers.

Refresh our memory from MIS300:

• Examples: Air conditioning System – Respiratory System – Printing System – Computer System.

Refresh our memory from MIS300:

• Information System: • Information systems have five key

elements: hardware, software, data, processes, and people (stakeholder)

• Hardware - the physical layer of the information system.

• Software – can be System software or Application software System Software manage the hardware

components. Application software consists of programs that

support data-to-day business functions and provides users with the information they require.

Refresh our memory from MIS300:

• Information System:

• Data – raw facts that describe a particular phenomenon such as the current temperature, the price of movie rental, or your age.

 Data consists of basic facts that are the system’s raw material

• Information – data that have a particular meaning within a specific context.

 Information is data that has been transformed into output that is valuable to users

• Processes - Describe the tasks and business functions that users, managers, and IT staff members perform to achieve specific results

People/ Stakeholders: • Who is a stakeholder?

• A stakeholder is any person who has an interest in (is affected by) an existing or proposed information system.

• Stakeholders can be technical or nontechnical workers.

• They may also include both internal and external workers.

• Stakeholders could be: 1. System Owners: also called clients & investors.

2. System Users-(Internal or External): Customers /employees

3. System Designers: People who know what is needed. Produce the blue prints for the builders.

4. System Builders: People who will create, deploy, and maintain the system.

5. System Analysts: specialists who study the problems and needs of an organization. They determine how to improve processes

6. Project Manager

Understanding The Business

 Companies use information technology as a weapon in the battle to increase productivity, deliver quality products and services, maintain customer loyalty, and make sound decisions.

 IT Professional must understand a company’s operations to design successful system.

Example: retail store, medical practices and hotel chain all have unique information systems requirements.

 Systems analysts use a process called business process modeling to represent company operations and information needs.

 Business process modeling requires a business profile and a series of models that document business processes

Understanding The Business Concepts

• Business Profile: is an overview of a company’s mission, functions, organization, products, services, customers, suppliers, competitors, and future direction.

• Business Process: is a specific set of transactions, events, and results that can be described and documented.

• Business Process Model (BPM): graphically displays one or more business processes, such as handling an airline reservation, filling a product order, or updating a customer account.

What is Information Systems Analysis and Design?

 A method used by companies to create and maintain systems that perform basic business functions.  such as keep track of customer names and addresses,

processing orders, and paying employees.

 Main goal: is to improve employee efficiency by applying software solutions to key business tasks. • A system analyst will be at the central of developing this

software.

What is Information Systems Analysis and Design? (Continued)

 Systems Analysts perform analysis and design based upon:  Understanding of organization’s objectives,

structure and processes.

 Knowledge of how to exploit information technology for advantage

 A structured approach must be used in order to ensure success, such as SDLC

What is Information Systems Analysis and Design? (Continued)

• Fig 1-1 illustrates the Systems Development Life Cycle, a four-phased approach used throughout this text

System Analyst:

• System Analyst: • Are specialists who study the problems

and needs of an organization.

• They determine how to improve processes.

System Analyst:

• A system analyst needs: • Knowledge: Understand both business and computing.

• Problem Solver: They identify problems and opportunities.

• Opportunities: to improve a situation despite the

absence of complaints

System Analyst Skills set:

o A systems analyst’s Skills set should include: 1. Analytical thinking skills. 2. Technical skills. 3. Managerial Skills 4. Interpersonal Skills. 5. Flexibility and adaptability

System Analyst Role in Systems Development

 Study problems and needs of an organization

 Determine best approach to improve organization through use of:

 People

 Methods

 Information technology

 Help system users and managers define their requirements for new or enhanced information systems

Systems Analysis and Design: Core Concepts

 Major goal: to improve organizational systems by developing or acquiring application software, and training employees in its use

 Application software, or a system: Designed to supports organizational functions or processes, such as inventory management, payroll, or market analysis …

 In addition, System: Turns data into information and includes:  Hardware and system software

 Documentation and training materials

 Job roles associated with the system

 Controls to prevent theft or fraud

 The people who use the software to perform their jobs

Systems Analysis and Design: Core Concepts (Continued)

Figure 1.2 illustrates all the components of a computer-based information system application.

Figure 1-2

addresses all the

dimensions of the overall system.

Emphasis on

application software

development, which

is the primary

responsibility as a systems analyst.

Systems Analysis and Design: Core Concepts (Continued)

 Software Engineering Process

 A process used to create an information system

 Consists of:  Methodologies

 A sequence of step-by-step approaches that help develop the information system

 Techniques  Processes that the analyst follows to ensure, complete and

comprehensive analysis and design

 Tools  Computer programs that aid in applying techniques

Systems Analysis and Design: Core Concepts (Continued)

The three elements work together to form an organizational approach to systems analysis and design

Systems Analysis and Design: Core Concepts (Continued)

 System

A system is an interrelated set of business procedures used within one business unit, working together for a purpose

― A system has nine characteristics

― A system exists within an environment

― A boundary separates a system from its environment

― A system takes input from outside, processes it, and sends the resulting output back to its environment.

 Characteristics of a System

1. Components

2. Interrelated Components

3. Boundary

4. Purpose

5. Environment

6. Interfaces

7. Constraints

8. Input

9. Output

 Important System Concepts:

1. Decomposition (Functional Decomposition)

2. Modularity

3. Coupling

4. Cohesion

 Important System Concepts:

1. Decomposition (Functional Decomposition)  The process of breaking down a system into smaller

components, also called subsystems

 Decomposition is a technique that allows the systems analyst to:

• Break a system into small, manageable and understandable subsystems

• Focus on one area at a time, without interference from other areas.

• Concentrate on component related to one group of users without confusing users with unnecessary details.

• Build different components at independent times and have the help of different analysts.

 Important System Concepts: continued

Decomposing an MP3 player into three separated physical subsystems.

Decomposing an MP3 player into three separated physical subsystems.

 Important System Concepts: continued

2. Modularity: It is a direct result of decomposition  Dividing a system into chunks/modules of a relatively uniform size.

 Modules simplify system design; each module comes with it is own functionality and design specifications.

3. Coupling: It is the extent to which subsystems depend on each other.  Subsystems that are dependent upon each other are coupled.

4. Cohesion: It is the extent to which a subsystem performs a single function

A Modern Approach to Systems Analysis and Design

― 1950s: focus on efficient automation of existing processes

― 1960s: advent of procedural third generation languages (3GL) faster and more reliable computers

― 1970s: system development becomes more like an engineering discipline

― 1980s: major breakthrough with 4GL, CASE tools, object-oriented methods

― 1990s: focus on system integration, GUI applications, client/server platforms, Internet

― The new century: Web application development, wireless PDAs and smart phones, component-based applications, per-use cloud-based application services.

A Modern Approach to Systems Analysis and Design

 Systems Integration • The process of building a unified information system out of

diverse components of purchased software, custom-built software, hardware, and networking.

• Allows hardware and software from different vendors to work together.

• Enables procedural language systems to work with visual programming systems.

• Visual programming environment uses client/server model.

Developing Information Systems and the Systems Development Life Cycle

• Systems Development:

Business information systems are developed by people who are technically qualified, business-oriented, and highly motivated.

The three elements work together to form an organizational approach to systems analysis and design

System Development Techniques and tools

• In addition to understanding business operations,

• systems analysts must know how to use a variety of techniques

such as

modeling, prototyping, and computer-aided systems engineering (Case) tools

to plan, analyze, design, and implement information systems

System Development Techniques and tools  Modeling: produces a graphical representation of a concept or process that

systems developers can analyze, test, and modify.

― A systems analyst can describe and simplify an information system by using a set of business, data, object, network, and process models.

o Business Model (Requirement Model): describes the information/ functions that a system must provide.

Requirement Modeling:  involves fact-finding to describe the current system.  Identification and structuring of the requirements for the new system, such

as outputs, inputs, processes, performance, and security.

System Development Techniques and tools  Modeling: produces a graphical representation of a concept or process that

systems developers can analyze, test, and modify.

o Process Model: describes the logic that programmers use to write code modules.

o Data model describes data structures and design.

We will use the process modeling and data modeling to continue the modeling process by learning how to represent graphically system data and processes

using traditional structured analysis techniques that treats processes and data as separated components

o Object model describes objects, which combine data and processes. It use object-oriented analysis (O-O) technique .

System Development Methods

• Structured Analysis • Systems development life cycle (SDLC)

• Predictive approach

• Uses a set of process models to describe a system graphically

• Process-centered technique

• Waterfall model

• The SDLC model usually includes steps as: • Systems planning

• Systems analysis

• Systems design

• Systems implementation

• Systems support and security

System Development Methods

• Object-oriented Analysis – Combines data & processes that

act on the data into things called objects

– Object is a member of a class

– Objects possess properties

– Methods change an object’s properties

System Development Methods

• Other Development Methods • Agile Methods

• Joint application development (JAD)

• Rapid application development (RAD)

Developing Information Systems and the Systems Development Life Cycle • Systems Development:

Business information systems are developed by people who are technically qualified, business-oriented, and highly motivated

• Systems Development Methodology • A standard process followed in an organization to conduct all the steps necessary to

• analyze

• design

• implement

• and maintain information systems.

Developing Information Systems and the Systems Development Life Cycle (Continued)

 Systems Development Life Cycle (SDLC) (Structured Analysis) – Series of steps used to manage the phases of development for an

information system

– Consists of four phases:

– Planning and Selection

– Analysis

– Design

– Implementation and Operation.

– Phases are not necessarily sequential

– Each phase has a specific outcome and deliverable

– Every company customizes the life-cycle model to its individual needs

Developing Information Systems and the Systems Development Life Cycle (Continued)

 Phases of the Systems Development Life Cycle: 1. Systems Planning and Selection

• Two Main Activities

• Identification of needs

• Investigation and determination of scope

2. Systems Analysis • Study of current procedures and information systems.

• Analysis has several sub-phases:

1. Determine requirements

2. Study and Structure requirements according to their interrelationships • Generate alternative designs

• Compare alternatives

3. Recommend best alternative.

• The output: a description of the alternative solution recommended by the analysis team.

 Phases of the Systems Development Life Cycle: (continued)

3. System Design • Logical Design

• Concentrates on business aspects of the system

• Physical Design • Technical specifications

4. System Implementation and Operation • Implementation

• Hardware and software installation

• Programming

• User Training

• Documentation

• Operation • System changed to reflect changing conditions

• System obsolescence

Alternative (Specialized) Approaches to System Development:

 In this chapter we will discuss Seven approaches (techniques, tools and methods) to system development:

1. Prototyping.

2. Computer-Assisted Software Engineering (CASE) Tools.

3. Joint Application Design (JAD)

4. Rapid Application Development (RAD)

5. Agile Methodologies

Alternative (Specialized) Approaches to System Development:

 Prototyping

 Building a scaled-down working version of the system.

 Advantages:

 Users are involved in design

 Captures requirements in concrete form.

Alternative (Specialized) Approaches to System Development: (Continued)

 Computer-Assisted Software Engineering (CASE) Tools  Automated software tools used by systems analysts to

develop information systems.

 Can be used throughout SDLC

 Product and tool integration is provided through a repository: A central repository provides integrated storage of diagrams, reports, and project management specifications.

Alternative (Specialized) Approaches to System Development: (CASE) Tools (Continued)

 General types of CASE tools 1. Diagramming tools enable graphical representation.

2. Computer display and report generators help prototype how systems “look and feel”.

3. Analysis tools automatically check for consistency in diagrams, forms, and reports.

Alternative (Specialized) Approaches to System Development: (CASE) Tools (Continued)

 General types of CASE tools 4. A central repository provides integrated storage of

diagrams, reports, and project management specifications.

5. Documentation generators standardize technical and user documentation.

6. Code generators enable automatic generation of programs and database code directly from design documents, diagrams, forms, and reports.

CASE Tools (Cont.)

Alternative (Specialized) Approaches to System Development : (Continued)

 Joint Application Design (JAD)

 Users, Managers and Analysts work together for several days

 System requirements are reviewed

 Structured meetings

 Rapid Application Development (RAD)

 Utilizes prototyping to delay producing system design until

after user requirements are clear

Alternative (Specialized) Approaches to System Development: (Continued)

 Agile Methodologies • Motivated by recognition of software development as fluid,

unpredictable, and dynamic.

• Three key principles

• Adaptive rather than predictive

• Emphasize people rather than roles

• Self-adaptive processes

When to use Agile Methodologies

• If your project involves: • Unpredictable or dynamic requirements

• Responsible and motivated developers

• Customers who understand the process and will get involved

Alternative (Specialized) Approaches to System Development: (Continued)

 Object-Oriented Analysis and Design (OOAD)

• Based on objects rather than data or processes

• Object: a structure encapsulating attributes and behaviors of a real- world entity

• Object class: a logical grouping of objects sharing the same attributes and behaviors

• Inheritance: hierarchical arrangement of classes enable subclasses to inherit properties of superclasses.

Summary

• Information systems analysis and design • Process of developing and maintaining an information system

• Modern approach to systems analysis • Process-oriented

• Data-oriented

Summary: (continued)

• Role of Systems Analyst

• Systems Development Life Cycle (SDLC) › Systems Planning and Selection

› Systems Analysis

› Systems Design

› Systems Implementation

Summary: (continued)

• Alternatives to Systems Development Life Cycle • Prototyping

• Rapid Application Development (RAD)

• CASE

• Joint Application Design (JAD)

• Participatory Design (PD)

• Agile Methodologies