System Analysis and Design

Introduction to System Analysis and Design

• System Analysis and Design (SAD) focuses on understanding, designing, and implementing information systems.
• SAD emphasizes systems, processes, and technology
• Systems involve hardware, software, data, and users for a common goal
• Processes involve sequences of tasks for a specific outcome
• Technology includes the tools, platforms, and infrastructure for building and operating systems
• SAD utilizes methodologies to develop high-quality Information Systems by combining Information Technology, people, and data to support business requirements.
• Methodologies are structured processes or frameworks that guide system development with steps for analysis, design, development, and implementation, such as Agile, Waterfall, or Spiral
• High-Quality Information Technology focuses on creating reliable and efficient technological solutions.
• The efficient technological solutions include software, hardware, and network systems that meet business needs
• People emphasizes the role of users, stakeholders, and IT professionals
• Input from users, stakeholders, and IT professionals are needed to understand requirements and ensure the system is user-friendly and effective

Data In System Analysis and Design

• Data management requires collection, storage, and retrieval of information
• Data in systems needs secure and efficient handling for informed decision-making
• It aims to align the information system with organizational goals.
• Doing so provides value by enhancing productivity, improving processes, and facilitating decision-making
• SAD encompasses a collaborative and systematic approach for developing technology solutions to meet specific business needs with high standards

System Analysis versus System Design

• System Analysis defines "what" a system should do before "how" it does it for system design
• System analysis provides a roadmap for effective systems to solve problems and support business requirements
• System analysis defines the blueprint, guiding design toward the actual system
• System analysis focuses on identifying system requirements
• System analysis gathers and analyzes data to define what a system should accomplish
• The components to system analysis includes understanding user needs, business processes, and potential problem solving
• System design deals with how the system will fulfill requirements from the analysis phase
• Ultimately, System Design translates the "what" from the analysis into detailed specifications for building the system.
• System Design considers architectural decisions, technology choices, and interface design

Core Concepts of SAD

• System Analysis and Design (SAD) mainly deals with software development activities that use the systems approach.
• Systems are created to solve problems
• It applies the systems approach to solving problems using computers with elements, processes, and technology
• Users need to understand organizational systems and then design appropriate computer-based systems for meeting an organization's requirements
• SAD uses a customized approach for problem-solving
• SAD is both a guided process with architecture and component design and a set of techniques such as surveys and user interface design

Defining a System

• A system involves components working together for objectives
• Input, processing, and output are the major components
• Components connect and are interdependent
• The objective demands output produced from processing inputs
• A well-designed system has a control element for feedback to achieve objectives
• National systems include political, economic, and educational systems
• Business systems refer to achieving an organization's aims through coordinating activities

Characteristics of a System

• Organization implies structure and order
• The process arranges components that helps to achieve objectives
• Business systems follow a hierarchical structure
• Computer systems are designed around I/O and a CPU
• Interaction refers to component functions tied to to other components/systems
• Various department interactions happen such as purchasing interactions with production or advertising with sales.
• A CPU must interact with other units to solve a problem
• Interdependence means that all system parts rely on each other
• Planned coordination and linkage happens to achieve an objective
• Integration ties a system together beyond shared locations into unified function
• Integration involves many parts of a system working together despite each part performing a specific function
• It produces a better result as a whole rather than if components work separately
• A central objective is the last characteristics of the system
• A Central objective may be real or stated
• User awareness is key to the objective well in advance

Elements of Systems Analysis

• The four elements in systems analysis are outputs, inputs, files and processes
• Aims must be determined to consider what an organization intends to achieve as the purpose behind the system
• Aim is vital in system work because a failure to define objectives means a failiure to know when aims have been achieved
• Input should be determinable from the output
• Information may not be readily available or properly designed
• Top management may be needed to obtain information
• A cost-benefit analysis can convince management for acquiring information
• Data which is wrong yields outputs will be wrong
• A system falls into arrears If data is not obtained in time
• Inputs must be in a proper format
• Data must be produced at the least cost
• Files are used to store data, which can be historical or generated internally and used to store facts
• Inputs undergo conversion into outputs
• Processes handle data through the computer by performing logical steps
• Processing requires a set of logical steps a computer must "programmed" to perform

Types of Systems

• Systems are classified as:
  • Physical or abstract systems
  • Open or closed systems
  • Deterministic or probabilistic systems
  • Man-made information systems
• Physical systems are tangible and static or dynamic
• Abstract systems are conceptual or non-physical
• Open system continually interacts with its environments by receiving inputs/delivering to the outside
• Closed systems are isolated from environmental influences, closed system are rare
• Deterministic system is one in which the occurrence of all events is perfectly predictable.
• Probabilistic system is one in which the occurrence of events cannot be perfectly predicted.
• Information systems reduce uncertainty through interaction between user and the analyst, forming relationship among decision makers
• An information system acts as a decision centre for personnel at all levels
• Information systems are designed as a set of procedures and operating systems designed around user-based criteria for planning, control and performance

Man-Made Information Systems

• Some practitioners fail to recognize that a business may have several information systems, each designed for a specific purpose
• The major systems are Formal Information Systems, Informal Information Systems, and Computer-based Information systems
• A Formal Information System is based on the organization represented by a the org chart which maps positions and their relationships and concerned with the pattern of authority, communication and work flow
• Informal Information Systems are an employee-based for personnel and vocational needs and help address work-related problems and which funnels information upwards through indirect channels.
• Informal systems that works within the framework of the business are useful
• Computer-based Information Systems depend mainly on the computer for handling business applications to meet a variety of business needs
• Computer-based Information Systems include Transaction Processing Systems (TPS), Management Information Systems (MIS), Decision Support System (DSS) and Office Automation Systems (OAS).

CBIS (Computer-Based Information Systems) Types

• Transaction Processing Systems (TPS): Fundamental systems processing business transactions in an organization, classify updates and retrieve the data.
  • A transaction is any event or activity that affects the whole organization and includes placing orders, billing customers, and hiring.
• Management Information System (MIS): A system for policy making, management planning, and control purposes.
  • MIS Provides management with information essential to perform effectively making business
  • Must be relevant, timely, accurate, complete and concise as is economically feasible.
• Decision Support Systems (DSS): A DSS must make decisions that are not highly structured, often called unstructured or semi-structured decisions with judgement.
  • A decision is considered unstructured if there are no clear procedures for making the decision and if not all the factors to be considered in the decision can be readily identified in advance.
• Office Automation Systems (OAS): A system increases efficiency by automating office work

System Development Life Cycle (SDLC)

• System development starts when improvement in a system is required and involves analysis and design (two major steps)
• It is the set of activities by the analysts, designers and users to implement information system
• The activities include Preliminary investigation, Determination of system requirements, Design of system, Development of software, Systems testing, Implementation, evaluation and maintenance
• Request clarification, Feasibility study, and Request approval are three parts of preliminary investigation in SDLC.
• Project requests must be examined and clarified to address poorly defined requests from the organization
• The feasibility study determines a preliminary analysis of the system's feasibility with technical, economic, and operational feasibility
• The systems analysis can be tested by a small group of skilled individuals who will have a small group study for information systems that involves or affects any organization
• A project request can be approved by estimating the costs and adjusting the project as necessary

SDLC Part II

• Analysing systems requires a solid understanding of a business
• Key questions arise which can be What is being done? How is it being done?
• To get at the real question analysis relies on obtaining accurate facts from those involved in the project
• Data flows, interviews and an open mind is required for success
• Design requires clearly outlining the purpose of a system which involves testing to see if the system fits the software provided by the designer
• Systems design involves detailed description, a system that describes clearly how a system must perform
• Information must be passed on for the purpose of software development and must be clearly spelled out
• Programmers will be chosen due to whether they can install purchased software or if they could develop new programs
• Programmers are also responsible for documenting what is coded
• Documentation must be testable, and carried through to to see if program applications have been fully installed
• System analysis must test software with users to see if anything is going wrong
• It should run according to specs
• Limited number of users are allowed to assess the system
• It is good to discover flaws before depending on the system
• All new functions need to be run on new equipment, trained users, and created data files
• All new or old systems should be run parallel to be compared

System Evaluation and Maintenance

• Evaluation must be performed to identify weaknesses
• Evaluation must be performed in terms of operational, organizational, user manager assessment and development performance
• Maintenance happens to eliminate errors and variations

Software Crisis

• Creating software needs insight into commercial/computer information that goes beyond the intuitive.
• There is an explosion towards software development
• When developing software, quantities of data are key.
• Software's crisis problems includes Programmer's Vs View Vs User's View

Programming Issues

• Programming problems includes compatibility, portability, documentation and lack of coordination
• Further complications comes in with detecting errors, piracy and maintenance

User issues

• User issues includes how to choose compatible software that works and to verify compatible compatibility for various software
• It is likely what is custom ordered may not be what ends up delivered

Who is a System Analyst?

• In short, a systems analyst conducts studies, identifies activities and objectives, and determines achieve those objectives
• Systems analysts need experience, must be familiar with people and business, data processing, communication and analytical skills and must be educated