Software System Analysis & Design Course. Chapter 1 The Systems Development Environment Essentials of Systems Analysis and Design 3 rd Edition Joseph.

Software System Analysis & Design Course

Chapter 1

The Systems Development Environment

Essentials of Systems Analysis and Design 3rd Edition

Joseph S. Valacich , Joey F. George , Jeffrey A. Hoffer

System Analysis & Design Course

Learning ObjectivesDefine information systems analysis and design.Discuss the modern approach to systems analysis and

design that combines both process and data views of systems.

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

Describe the different sources of software.Describe three types of information systems:

Transaction Processing Systems (TPS) Management Information Systems (MIS) Decision Support Systems (DSS).

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Learning Objectives (continued)

Describe the information systems development life cycle (SDLC).

Discuss alternatives to the systems development life cycle, including a description of the role of computer aided software engineering (CASE) tools in systems development.

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What is Information Systems Analysis and Design?

• A method used by companies to create and maintain systems that perform basic business functions such as keeping 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 structured approach must be used in order to ensure success

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What is Information Systems Analysis and Design?

• Systems Analyst performs analysis and design based upon:– Understanding of organization’s objectives,

structure and processes– Knowledge of how to exploit information

technology for advantage• Fig 1-1 illustrates the Systems Development Life Cycle, a four-

phased approach used throughout this text.

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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, supports organizational functions or processes.

• 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

• Figure 1-2 illustrates all the components of a system.

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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 Most methodologies incorporate several development techniques, such as direct observations and interviews with users of the current system.

– Techniques• Processes that the analyst follows to ensure thorough, complete,

and comprehensive analysis and design planning and managing the activities in a systems development project designing the reports, such as invoices

– Tools• Computer programs that aid in applying techniques such as

computer-aided software engineering (CASE) tools, that make it easy to use specific techniques.

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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.

Characteristics of a System• Components• Interrelated Components• Boundary• Purpose• Environment• Interfaces• Constraints• Input• Output

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Important System Concepts• Decomposition– The process of breaking down a system into

smaller components– 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 pertinent to one group of

users without confusing users with unnecessary details• Build different components at independent times and

have the help of different analysts

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Important System Concepts

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Important System Concepts (continued)

• Modularity– Process of dividing a system into modules of

a relatively uniform size– Modules simplify system design

• Coupling– Subsystems that are dependent upon each

other are coupled

• Cohesion– Extent to which a subsystem performs a

single function

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A Modern Approach to Systems Analysis and Design

• Systems Integration– 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. Internet is also organized in a client/server format

– Enterprise-wide system from companies such as SAP (Systems, Applications, and Products in Data Processing) Oracle , JDE

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A Modern Approach to Systems Analysis and Design

• Systems Integration– Developers assemble systems by choosing and

implementing specific modules. – an enterprise-wide system may handle all human

resources management, payroll, benefits, and retirement functions within a single, integrated system.

– organizations develop systems in-house anymore.

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A Modern Approach to Systems Analysis and Design

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Your Role in Systems Development• Primary Responsibility rather than other. key to the

systems development process• Position is found in small and large companies.• to study the problems and needs of an organization

in order to determine how people, methods, and information technology can best be combined to bring about improvements in the organization.

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

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Skills of system analyst • Analytical skills: able to understand the organization

and its functions, to identify opportunities and problems, and to analyze and solve problems.

• Technical skills: able understand the power and the limitations of information technology. Programming languages, Operation systems , Hardware platforms,

• Management skills: able to manage teams, projects, risks and change.

• Interpersonal skills: able to work with other analyst and programmers , end users and professionals, effective writing and oral communications, leading meetings, conferences, interviews, good listener.

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Your Role in Systems Development

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Outsourcing

• Practice of another organization developing and/or running a computer application for your organization

• Many types of working arrangements• Should be considered as one possible

alternative to developing a system

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Sources of SoftwareWhat is done when a problem raised ?•When developing information systems to deal with such problems, an organization and its systems analysts have several options:•Go to Information Technology Services Firms, HP•Packaged Software Providers on shelf SW (Buy)•Implement Wide Enterprise Solutions Software SAP•Open-Source Software•Use In-House stuff for developing solution•Out sourcing system development and operations

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Types of Information Systemsand Systems Development

• Transaction Processing Systems (TPS)– Automate handling of data about business activities

(transactions)

• Management Information Systems (MIS)– Converts raw data from transaction processing system into

meaningful form

• Decision Support Systems (DSS)– Designed to help decision makers– Provides interactive environment for decision making

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Sources of Software Components

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SDLC• System Development Methodology SDM– Any Organizations use a standard set of steps, called a

SDM, to develop and support their information systems. Like many processes, the development of information systems often follows a life cycle.

– For example, a commercial product, such as a Nike sneaker or a Honda car, follows a life cycle: It is created, tested, and introduced to the market. Its sales increase, peak, and decline. Finally, the product is removed from the market and is replaced by something else.

– Phases are not necessarily sequential.– Each phase has a specific outcome and deliverable.– Individual companies use customized life cycle

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Developing Information Systems and the SDLC

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SDLC- Systems Planning and Selection– Main Activities

• Identification of need for enhancing the current system or for new system ( written plane of IS dept.), schedule for developing new system.• A feasibility study is conducted before the

second phase of the SDLC to determine the economic and organizational impact of the system.• Investigation and determination of scope• The final presentation to the organization’s

management of the plan for proceeding with the subsequent project phases is usually made by the project leader and other team members.

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• The analyst studies the organization’s current procedures and information systems used to perform tasks such as general ledger GL, shipping, order entry, machine scheduling, and payroll.

• Determine requirements : what the users want from a proposed system a careful study of any current systems, manual and computerized, that might be replaced or enhanced as part of this project.

• Generate alternative initial designs to match the requirements

• Compare alternatives and Recommend best alternative

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

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SDLC- Systems Planning and Selection

• The recommended alternative solution is presented into logical and then physical system specifications.

• Input screens, output screen and reports.• Databases, and computer processes. • Environment Independent ( HW and SW)

• Logical Design• Concentrates on business aspects of the system

• Physical Design• Technical specifications.• The analyst team decides which programming languages , DBMS , HW ,

Operating system , Network environment.

• The final product of the design phase is the physical system specifications presented in a form, such as a diagram or written report, ready to be turned over to programmers and other system builders for construction.

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SDLC- System Design

SDLC – Implementation and operation• System Implementation and Operation– Implementation• Coding: Write Programs the make up the system.• Testing : Testing the program to find errors if exist.• Installation: Application is installed on the New HW.• User is introduced to the system an trained on it• Documentation

– Users sometimes find problems with how it works and often think of improvements.

– The amount of time and effort devoted to system enhancements during operation depends a great deal on the performance of the previous phases of SDLC.

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Products of the SDLC

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Alternative Approaches to Development• Prototyping– Building a scaled-down working version of the system– The analyst works with users to determine the basic

requirements for the system. – The analyst then quickly builds a prototype. – the users check it and tell the analyst what they like and do not

like about it. – The analyst uses this feedback to improve the prototype and

takes the new version back to the users. – This iterative process continues until the users are relatively

satisfied with what they have seen.– Advantages:

• Users are involved in design

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Alternative Approaches to Development• Prototyping

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Approaches to 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.– General types of CASE tools• Diagramming tools• Computer display and report generators• Analysis tools• Repository• Documentation generators• Code generators 39

Selecting Off-the-Shelf Software• Cost: comparing the cost of developing the same system in-house

with the cost of purchasing or licensing the software package• Functionality: the tasks that the software can perform and the

mandatory, essential, and desired system features• Vendor support: whether or how much support the vendor can

provide and at what cost.• Viability of vendor: can the software adapt to changes in systems

software and hardware• Flexibility: how easy it is to customize the software• Documentation: is the user’s manual and technical

documentation understandable and up-to-date• Response time: how long it takes the software package to

respond to the user’s requests in an interactive session• Ease of installation: a measure of the difficulty of loading the

software and making it operational• compatibility with currently used application

software and HW. hardware and system software

Validating Purchased Software Information

• Use a variety of information sources:– Collect information from vendor– Software documentation– Technical marketing literature

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Questions1. What is the information systems analysis and design?2. What is meant by the system, list the main characteristics of

the system? 3. What is meant by methodology , Tools , Techniques?4. What is decomposition? Coupling? Cohesion?5. In what way are organizations systems?6. Describe the major Types of Information systems?7. What is meant by outsourcing? And what are the main

sources of software?

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Questions8. What is the main role of the analyst? And what are the skills

that must be achieved in the system analysis?9. List and explain the different phases in the systems

development life cycle.10. What is prototyping?11. What are CASE tools? What is a CASE repository and how is it

used?12. How can you decide among various off-the shelf software

options? What criteria should you use?

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