System Analysis Mr Ahmad AlGhoul Learning Objectives n
System Analysis - Mr. Ahmad Al-Ghoul
Learning Objectives n n n Describe systems analysis phase activities and the end product of the systems analysis phase Describe the Unified Modeling Language (UML) Describe Functional Decomposition Diagram ( FDD ) Explain why analysts using models Describe CASE tools, objectives, and types Avicenna System Analysis and Design System Analysis 2
Learning Objectives n n n List and describe system requirements, including outputs, inputs, processes, performance, and controls Explain the importance of scalability Define total cost of ownership (TCO) and explain the concept Avicenna System Analysis and Design System Analysis 3
Introduction n n The overall objective of the systems analysis phase is to understand the proposed system, ensure that it will support business requirement, and build solid foundation of system development. Systems Analysis Activities n Avicenna The systems analysis phase includes three main activates n Requirements modeling n Data and process modeling n Development Strategies System Analysis and Design System Analysis 4
Systems Analysis Phase Overview n requirements Modeling n Requirements modeling involves n Fact finding n Avicenna Describing the current system and identification of the requirements for the new system which includes n Outputs: electronic or printed information produced by the system n Inputs: data that enters the system n Processes: the logical rules that are applied to transform the data into information n Performance: the system characteristics, speed, volume, capacity, availability, and reliability n Security: hardware, software, and procedural controls that protect the system and data from internal or external threats System Analysis and Design System Analysis 5
Systems Analysis Phase Overview n Data and process modeling n n Represent graphically system data and process using various techniques. Development Strategies n n Evaluation of alternative solutions Preparation of the system requirements document n Avicenna System requirements document is an overall design for the new system System Analysis and Design System Analysis 6
Systems Analysis Phase Overview n Modeling tools and techniques Modeling involves graphical methods and nontechnical language that represent the system at various stages of development n There are various tools to describe business processes, requirements, and user interaction with the system n Avicenna System Analysis and Design System Analysis 7
Modeling Tools and Techniques n Analysts using models to: Concentrate on important features of the system, pay less attention to less important ones; n Able to respond to changes or changes in user’s requirements with low cost and risk; n Properly understand users’ environment and write documents in the same way that designers and programmers construct the system. n Avicenna System Analysis and Design System Analysis 8
Modeling Tools and Techniques n CASE Tools ( computer-aided software engineering ) n n Avicenna CASE tools have been developed for internal use and for sale by several firms, including Oracle ( Designer), IBM ( Rational Rose ) Automated software tool used by systems analysts to develop information systems Used to support or automate activities throughout the systems development life cycle (SDLC) CASE tools include diagramming tools for data flow diagrams and other graphical aids, screen and report design tools, and other special-purpose tools System Analysis and Design System Analysis 9
Modeling Tools and Techniques n Objectives of CASE n n n n n Avicenna Improve quality of systems developed Increase speed of development and design Ease and improve testing process through automated checking Improve integration of development activities via common methodologies Improve quality and completeness of documentation Help standardize the development process Improve project management Simply program maintenance Promote reusability Improve software portability System Analysis and Design System Analysis 10
Modeling Tools and Techniques n Functional Decomposition Diagram ( FDD ) n n n Avicenna A top-down representation of a function or process A function diagram only shows what to do not how to do. FDD is a process of division, from a higher function to appropriate smaller functions. FDD need to be presented clearly, simply, exactly, and fully. FDD can be used at several stages of systems development System Analysis and Design System Analysis 11
Modeling Tools and Techniques Four-level functional decomposition diagram (FDD) of a library system. Avicenna System Analysis and Design System Analysis 12
Modeling Tools and Techniques n Unified Modeling Language ( UML ) UML is a method of visualizing and documenting software systems design n UML uses object-oriented design concepts n UML is independent of any specific programming language n UML used to describe business processes and requirements generally n UML provides various graphical tools n Avicenna System Analysis and Design System Analysis 13
System Requirements Checklist n System Requirements Checklist System developers must identify and describe all system requirements n System Requirements are a characteristics or features that must be included in an information system to satisfy business requirements and be acceptable to users n Avicenna System Analysis and Design System Analysis 14
System Requirements Checklist n Five categories of system requirements Outputs n Inputs n Processes n Performance n Controls n n In the next slides some examples of system requirements Avicenna System Analysis and Design System Analysis 15
System Requirements Checklist n Outputs n n The Web site must report online volume statistics every four hours, and hourly during peak periods Inputs n Avicenna The department head must enter overtime hours on a separate screen System Analysis and Design System Analysis 16
System Requirements Checklist n Processes n n Performance n n The student records system must calculate the GPA at the end of each semester Response time must not exceed four seconds Controls n Avicenna An employee record must be added, changed, or deleted only by a member of the human resources department System Analysis and Design System Analysis 17
Future Growth, Costs, and Benefits n In addition to the system requirements, system analyst must consider Scalability n Total Cost of Ownership n Avicenna System Analysis and Design System Analysis 18
Future Growth, Costs, and Benefits n Scalability System’s ability to handle increased business volume and transactions in the future n A scalable system offers a better return on the initial investment n To evaluate, you need information about projected future volume for all outputs, inputs, and processes n Avicenna System Analysis and Design System Analysis 19
Future Growth, Costs, and Benefits n Total cost of ownership (TCO) n n Avicenna A number that is used in assessing costs, which includes ongoing support and maintenance costs, as well as acquisition costs. TCO especially important if the development team is evaluating several alternatives One problem is that cost estimates tend to understate indirect costs Systems analysts should try to identify indirect costs and include them in TCO estimates System Analysis and Design System Analysis 20
Sequence Summary n n n n The systems analysis phase includes three activities: requirements modeling, data and process modeling, and consideration of development strategies The main objective is to understand the proposed project and build a solid foundation for the systems design phase You identify the business-related requirements for the new information system, including outputs, inputs, processes, performance, and controls You consider scalability to ensure that the system can support future growth and expansion You also estimate total cost of ownership (TCO) to identify all costs, including indirect costs UML is a method of visualizing and documenting software systems design CASE tools are automated software tool used by systems analysts to develop information systems Avicenna System Analysis and Design System Analysis 21
Sequence Summary n In this Sequence we have n Described the systems analysis phase including three activities: requirements modeling, data and process modeling, and consideration of development strategies n Explained the main analysis objective that is to understand the proposed project and build a solid foundation for the systems design phase n identified the business-related requirements for the new information system, including outputs, inputs, processes, performance, and controls n Identified the fact-finding process includes interviewing, document review, observation, questionnaires, sampling, and research n Described the Unified Modeling Language (UML) n Described Functional Decomposition Diagram ( FDD ) n Explained why analysts using models n Describe CASE tools, objectives, and types Avicenna System Analysis and Design System Analysis 22
Reference [1] System Analysis and Design, Sixth Edition Authors: Gary B. Shelly, Thomas J. Cashman and Harry J. Rosenblatt Publisher: SHELLY CASHMAN SEWIES. [2] Modern Systems Analysis and Design Third Edition Authors: Jeffrey A. Hoffer , Joey F. George, Joseph S. Valacich Publisher: prentice hall Avicenna System Analysis and Design System Analysis 23
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