Unit 1: Introduction to System Analysis and Design PDF

UNIT 1 INTRODUCTION TO SYSTEM ANALYSIS AND DESIGN Overview In this unit, students will learn the system concepts, information systems, as well fundamentals of system analysis and Design and also determine system development lifecycle phrases. They will also learn the various system development me...

UNIT 1 INTRODUCTION TO SYSTEM ANALYSIS AND DESIGN Overview In this unit, students will learn the system concepts, information systems, as well fundamentals of system analysis and Design and also determine system development lifecycle phrases. They will also learn the various system development methodologies including waterfall, Rapid Application Development (RAD), and Agile methods. Unit Objectives At the end of this unit, the learner should be able to: 1\. Define system and information system. 2\. Explain components of Information system. 3\. Describe stages of system development lifecycle. 4\. Identify the system development methodologies. 5\. Differentiate among Waterfall model, RAD and Agile methods. INTRODUCTION TO SYSTEM ANALYSIS AND DESAGICT Form Four Lesson 1 INTRODUCTION TO SYSTEM ANALYSIS AND DESIGN Learning Objectives At the end of the lesson, the learner should be able to: 1\. Describe the system and its characteristics. 2\. Define information system. 3\. Identify the five key components of information system. 4\. Explain the concept of system analysis and design. 5\. Describe system analyst. 6\. Discuss in detail the system development life cycle. Overview In this lesson, we will learn about the basic concepts of system and informatie systems as well as the fundamental aspects of system analysis and design. We also discover the stages of system development life cycle. 1.0 What is a system? The term system is originally derived from the Greek word systema, which indicate a structured relationship among functioning units or components. A system is interconnected set of business procedures used within one business unit working together for a purpose. Normally we use the transportation system every day the telephone system, the accounting system, the production system, and for over b decades, the computer system. Similarly, business system consisting of interrelate departments (subsystems) such as production, sales, finance, human resou personnel, and an information system. The study of system concepts has three fundamentals implications: 1\. A system must be designed to meet predefined targets. 2\. The components have to have interrelationships and interdependence 3\. The organization\'s goals as a whole have a higher priority than its subsys goals. SIGN Characteristics of a System. Interrelated Components: works together with information systems to collect process, store and disseminate information to support decision making. Environment: It refers to the state of a computer - determined by which programs are running on basic hardware and software characteristics. Interfaces: It is a device or a program that allows users to communicate with a computer. Interfaces exchange between software, computer hardware, peripheral devices, humans, and or a combinations of these. Input: means to provide or give something to the computer or any other electronic device Output: Any information that is processed by and sent out from a computer or any other electronic device. 1.2 Information System Information systems are a combined network of hardware, software, and telecommunications networks that users use to collect, create, and distribute useful data, from organizational settings. Examples of information systems include the following: 1\. Marketing information system 2\. Payroll system 3\. Human resource management system 4\. Library management system, school management system 5\. University management system 6\. Restaurant Management system 7\. Accounting management system among others. The Components of Information Systems information syste The digital age introduced a new dimension to schools, universities, agencies multitude of other organizations: a set of components called thei which offers with gathering and organizing data and information. Informat systems have five essentials components namely: Hardware, Software, Dea People, and Processes. People Hardware Processes 10010010 101011101010 10010101101010 010101010010010 10100010101110 100110010101 100101010 Data Figure 1.1: Information System Software 1\. Hardware Hardware contains everything in the physical layer of the information system. example, hardware can consist of: Servers Workstations Networks Telecommunications equipment Fiber-optic cables Cellular devices Scanners Digital capture devices Different technology-based infrastructure As new technology advances, producers race to market the innovations and reap the rewards. INTRODUCTION TO SYSTEM ANALYSIS AND DESIGN ICT Form Four Student Book 2\. Software The hardware desires to know what to do, and that is the role of the software. Generally, software refers to the programs that manage the hardware and produce the favored information or result. Software can be broken down into two main categories: 1\. System software 2\. Application software. The core piece of system software is the Operating system, such as Windows or other operating systems which manages the hardware\'s operation. Application software is intended for specific tasks, such as handling a spreadsheet, creating a document, or designing a Web page. 3\. Data The third component is data and it is the raw material that an information system transforms useful information into. An information system can store the data at different locations called tables. Linking the tables helps the system to obtain detailed information. 4\. People People who have interest in an information system are called stakeholders. Stakeholders include top management, middle management groups who are responsible for the system. The users both inside and outside of the company interact with the system and of course, IT team members, such as systems analysts, programmers, and network administrators who develop and support the system. 5\. Process A process is a set of actions taken to attain a desired result or objective, Information systems have become more aligned with organizational processes, bringing greater productivity and better control to those processes. 1.3 Purpose of information System The following are some of the purpose of information system: i\. Provide information that assists with strategic planning. The processed information usually helps in making long term plans for an organization. ii\. Better Performance and increase productivity iii\. Support the distribution of information to different departments of organization for operation purpose 5 1.4 System Analysis and Design Systems Analysis and Design (automu is the mechanism by which people build 1.5 System information systems. It is remarkable that people who do systems analysis design produce business information systems which are used internally organization, sold commercially via mail or web, order or retail, store and Imbedo The System policies and is used to p produce h customer. which de in products. System Analyst A system analyst is a title given to a person who studies the problems and nees maintain of an organization looking for improvement opportunities for improving qual of service or product, reducing cost and increasing the income or profit. Normal system analyst should have the following skills: Working knowledge of information technology Computer programming experience and expertise General business knowledge General problem-solving skills Good interpersonal communication skills Good interpersonal relations skills Flexibility and adaptability Character and ethics INTRODUCTION Managers External companies 1. 1. S It S Software programmers System stakeholders Systems analyst Vendors and suppliers Technical specialists Users Figure 1.2: System Analysis and Design TO SYSTEM ANALYSIS AND DESIGN 1.5 System Development life cycle ICT Form Four Student Book The System Development Life Cycle (SDLC) is a conceptual model that incorporates policies and procedures to build or alter system during their life cycles. This method used to provide sorte for technical and non-technical activities in orde the produce high quality software that meets the standards and expectations of the customer. System development life cycle consists of details stages and activities ems and needs maintain and support a software system. which describes how to plan, analysis, design, develop, testing, deployment, nally within the and imbedde proving quality profit. Normally Planing Maintenance Analysis Deployment Design Testing Coding 1.6 Stage of System Development life cycle 1.6.1. Planning: System planning phase is the first phase in the systems development life cycle. It determines whether or not there is the need for a new system to achieve the strategic goals of a company. The aim of this phase is to conduct a preliminary investigation to determine opportunity or issue relevant to the Information Technology. The preliminary investigation is an essential stage because the result will affect the whole development process. Advantages It is relatively easy to analyze. You can contact a wide sample of the population at a relatively low cost. Respondents of survey have time to think about their answers; they are not usually required to reply immediately. Disadvantages Form Four Student Book \| Respondents may misunderstand questions because of poor design and ambiguous language. Respondents may ignore certain questions. There is a risk of questionnaire fatigue if surveys are carried out too frequently. d\) Document Review This method is extremely important because it involves investigating the currer system documentations. System analyst should review all the documents of curre systems in order to obtain accurate and complete information. systems in order to obtain accurate a Advantages Analyst can see for The analyst is able to review previous solutions and recommendations have been made on the system. himself how the paper system operates. Disadvantages It can be a very time-consuming exercise. It is a fairly costly method to use. d Th 1. a a Requirement Specification The deliverable f for analysis stage is the system requirements document. Ther the requirement should include the following; a\) Inputs b\) Outputs c\) Control d\) Data storage e\) Processing requirement INTRODUCTION TO SYSTEM ANALYSIS AND DESIGN ICT Form Four Student Book \| System analyst should produce quality requirement documents which meets the expectations of the customer. 1.6.3. Design Figure 1.6: Document Review The goal of the systems design stage is to build a physical model that will fulfill all documented requirements for the system. At this stage, you design the user interface and define necessary outputs, inputs, data storage and processes. Furthermore, you also design internal and external controls, including computer-based and manual functions to ensure that the system is efficient, accurate, maintainable, and safe. Moreover, you also define the application design which is used by programmers to turn the conceptual design into programs units and code. Finally, the main result of this stage is the system design specification which is submitted for review and approval to management and users. User interface Design A user interface define how users communicate with a computer system, and involves all the hardware, software, screens, menus, functions, performance, and features that affect two-way communications between the user and the system. INTRODUCTION TO SYSTEM ANALYSIS AND DESIGN ICT FOR Four Student Book INTRODUCTION Input design This is the de input specific The user interface design is the design of user interface for system which focuse on the usability of the software. The main goal of this aspect is to make the user interaction as easy as possible in terms of achieving user goals in the system. An Example of User Interface (GUI) Student Registration system Student ID Save Cancel Student Name Characteristics of a good user interface 1\. Consistent layout. 2\. User friendly. 3\. Build user interface which is simple and easy to use, 4\. Enhance user productivity, 5\. Make the user interface easy for users to seek support or fix errors, Characteristics of a good user interface 2\. User friendly. 3\. Build user interface which is simple and easy to use, 4\. Enhance user productivity, 5\. Make the user interface easy for users to seek support or fix errors, Output design This concept will be used to produce processed information from the system b on output specification Input design This is the design of interface to be used for data entry into the system based on input specifications. Data storage design Sample of an input design This process involves creating structure files and storages that will accommodate input data and results of processing. The files and data storage designed at this level are greatly influenced by the specifications of inputs, outputs, and processes. This is a stage where by the structure of tables are designed by the identification of data storage types A sample file structure Data Type Field Name Number Student ID Text Student Name Process Design This process includes creating procedures that will be used in processing data based on the specified processing requirements, for example, creating queries and macros that will meet the processing needs of the system. INTRODUCTION TO SYSTEM ANALTAND DESIGN INTRODUCTION Action Close Comment Close a specified window Object type Object name From Student Registration Save Prompt Controls Design ICT Form Four Student Book \| This involves coming up with policies that guide data processing and interaction with the system. They are determined by system controls requireme Sample of control design (user access policies) User group 1.6.5. T Administrators Access Level The mai Configure, upgrade and install syste requirer Input, delete. change data are as fo Data entry supervisors Input data Data entry clerks View components, mor Guest System Design Sample User group Administrators Access Le Configure, upgr requ Data entry supervisors Data entry clerks Input data Input, delete. change Guest View system are as follo 1\. U Each For Good System Design System design is the process of defining the architecture, components, modules, interfaces and data for a system to satisfy specified requirement of the users. Types of system design are; 1\. Logical 2\. Physical Design. Logical design relates to abstract representations of the input, outputs and data flow of the system. To represent the logical design of a system we use different diagram like Entity Relation Diagram. Moreover, the physical design is related to actual input and output processes of the system. 1.6.4. System Construction The main goal of this phase is coding of the proposed system by using an appropriate computer language. Making the code clear and effective enables one to develop and understand easily. A well-written code makes it easy to read and understand and this reduces maintenance cost. 16. Testing The main goal of this process is to fix errors. Errors in cording, planning and requirements are corrected. There are many ways of testing system. Some of them are as follows Unit testing Integration testing ↓ System testing ↓ Acceptance testing 1\. Unit testing Figure 1.8: System Testing is facing ent to Each unit in the system is tested. Outputs are tested against the given output. For example, testing the units related to the Accounts branch and establishment nd branch independently. TO SYSTEM ANALYSIS IND Form Four Student Book 2\. Integration testing 1 Units already tested and debugged are integrated to form the complete syst and the integrated system is tested at this stage. 3\. System testing This is the complete system is tested for its outputs for the given inputs. 4\. Acceptance testing Acceptance or user acceptance testing is carried out at the late stages of te This testing is carried out at with the users of the system and the user is allo use the system. Either the user approves or request for more improvements 1.6.6. Deployment of the system Deployment (install and use) of the system which has been tested and debu is carried out at this stage. There are different deployment approaches to dep system. They are as follows: Direct deployment: This method involves the old system being comple dropped and a new system being completely implemented at the same Parallel deployment: This method involves both the old system and potential replacement are run together for a time until everyone is ass that the new one functions correctly Pilot deployment: With the pilot method of implementation (or convers the new system is installed for a small number of users. These users le use and evaluate the new system. Once the new system is deemed to performing correctly then the system is installed and used by all. Phased deployment: The phased method of implementation (or conven from the old system to a new system involves a gradual introduction of new system whilst the old system is progressively discarded.. Maintenance This continuous process of system modifications is known as maintenance and will occur throughout the operational life cycle of the system. Normally, once the system has been installed, and customers begin using the developed system, the following three activities occur; Bug (error) fixing - bugs are reported because of situations that are not being checked at all Upgrade - Upgrading the application to the latest software versions, Enhancement - Adding some new functionality to the current software INTRODUCTION TO SYSTEM ANALYSIS AND DESIG orm Four Student Book \| ENTER The follo Lesson 2 SYSTEM DEVELOPMENT METHODOLOGIES Learning Objectives At the end of the lesson, the learner should be able to: 1\. List and Identify system methodologies. 2\. Differentiate between Agile Method and Waterfall Model. 3\. Explain the concept of RAD Model. Overview 4\. Identify stages of RAD. In this lesson, we will learn about the various system development methodolor including Waterfall, Agile Rapid Application Development (RAD). Furthermore Llu dorcribe the benefits and drawbacks of system development models 2 SYSTEM Rec Yes Learning Objectives At the end of the lesson, the learner should be able to: 1\. List and Identify system methodologies. 3\. Explain the concept of RAD Model. 4\. Identify stages of RAD. 2\. Differentiate between Agile Method and Waterfall Model. Overview In this lesson, we will learn about the various system development methodo including Waterfall, Agile Rapid Application Development (RAD). Furthermo will also describe the benefits and drawbacks of system development mode 2.0 Waterfall Model The Waterfall Model was the first methodology to be introduced. It also of several stages of a linear development. It is really easy to understand and In a waterfall model, each step must be completed before the next pha commence and the phases do not overlap. Moreover, to develop an informa system using the waterfall methods, you need the following consideration. First identify requirements. Complete one stage before going to the next phase. The result of the developed system is found at the final stage This model has a limitation of developing a system that is different to what the wants as the user sees the system at the end of the Life Cycle. INTRODUCTION TO SYSTEM ANALYSIS AND DESIGN ICT Form Four Student Book \| The following Figure illustrates the different phases of the Waterfall Model. Requirements Design Development Testing Deployment Maintenance Figure 2.1: Waterfall Model The advantages of waterfall model Easy and simple to understand and use. Easy to handle due to model stiffness. There are unique deliverables and a review process for each step. Phases are processed and finished one at a time. Fits well for smaller projects where there is a clear understanding of the specifications Phases are clearly described and the milestones well known Activities easy to manage and process and results are well documented. The disadvantages of waterfall model High risk and uncertainty levels. Not a suitable model for object-oriented and complex projects. Poor methodology for long and ongoing projects. Progress within stages can be difficult to measure. Cannot meet changing requirements. 2.1 What is agile method? Agile is a mechanism in which a team can manage a project by breaks tion with s stakehd Into many stages and requiring continuous collaboration Continual development and iteration at each stage. The Agile approach be Clients explaining how the end product will be used and what issue it will clarifies the customer\'s expectations to the project team. Once the wors teams cycle through a process of planning, executing, and evaluating whi Just change the final deliverable to fit the customer\'s needs better. Co cooperation between team members and with project stakeholders is es making fully informed decisions. some Less via Mo It goes Lac Pre Examples of Agile Methodology. The most common examples are Scrum, extreme Programming (XP), Featu Development (FDD), Dynamic Systems Development Method (DSDM Software Development (ASD), Crystal, and Lean Software Development Teams generally pick one or two methods INTRODUCTION TO SYSTEM ANALYSIS AND DESIGN ICT Form Four Student Book Customer satisfaction, is quick, continuous development and delivery of usable application. Advantages of Agile Method Users, developers, testers and emphasize rather than processes and tools. Product is produced rapidly and delivered regularly (weeks rather than product owner constantly interact to A face-to-face conversation is the months.) best method of communication. given continuous attention to technological excellence and good It has a design Every day and close collaboration between entrepreneurs and developers. Frequent adaptation to changing circumstances. Even late changes in requirements are welcomed. Disadvantages of agile Method Less predictability. For some software deliverables, developers cannot quantify the full extent of required efforts. More time and commitment. Greater demands on developers and clients. Lack of necessary documentation. Project easily falls off track. Iteration Extreme Programming (XP) 2.3 Rapid Application Development (RAD): informatio It is a team-based method which accelerates the development of systems and produces a functioning information system. It also highlights the fa and iterative release of prototypes and applications. RAD ANALYSIS AND QUICK DESIGN DEMONSTRATE PROTOTYPE CYCLES BUILO C B REFINE TESTING IMPLEMENTATION Five steps or phases in RAD Step 1. Define and finalize project requirements During this step, stakeholders sit together to define and finalize project requirement such as project goals, expectations, timelines, and budget. When you have clean defined and scoped out each aspect of the project\'s requirements, you can se management approvals. INTRODUCTION TO SYSTEM ANALYSIS AND DESIGN ICT Form Four Student Book Step 2: Begin building prototypes As soon as you finish scoping the project, you can begin development. Designers and developers will work closely with clients to create and improve upon working prototypes until the final product is ready. Step 3: Gather user feedback In this step, prototypes and beta systems are converted into working models. Developers then use feedback from users to tweak and improve prototypes and create the best possible product. Step 4: Test, test, test This step requires you to test your software product and ensure that all its moving parts work together as per client expectations. Continue incorporating client feedback as the code is tested and retested for its smooth functioning. Step 5: Present your system This is the final step before the finished product goes to launch. It involves data conversion and user training. Some of the key advantages of RAD are: Enhanced quickly flexibility and adaptability as developers can make adjustments during the development Quick iterations process. that reduce development time and speed up delivery. Encouragement of code reuse, which means less manual coding, less room for errors, and shorter testing times. satisfaction due to high-level collaboration and Increased customer coordination between stakeholders (developers, clients, and end users). Better risk management as stakeholders can discuss and address code vulnerabilities while keeping development processes going. Disadvantages of RAD Need strong team and individual performance for identifying busine requirement. Not all applications can be modulated using or be built using RAD. It requires highly skilled developers or designers. High dependency on modeling skills. 0 Less time can cause problem. Need strong team and individual performance for identifying b requirement.. Not all applications can be modulated using or be built using RA It requires highly skilled developers or designers. High dependency on modeling skills. Less time can cause problem Activity 1 1\. List and identify the system development methodologies 2\. Discuss in details the stage of Agile Model 3\. Explain the waterfall and RAD models