Systems Analysis & Design: Chapter 1

• Systems analysis and design is taught within the Information Systems department.
• These notes relate to the course "Systems Analysis and Design".
• The textbook "Essentials of System Analysis & Design" is recommended.
• Additional resource: "Systems_Analysis_Design_UML_5th ed".
• Lecture materials can be found on Microsoft Teams.
• The course prerequisite is Computer Science Fundamentals.
• Assessment weighting includes:
  • Final term examination: 50 points
  • Oral exam: 10 points
  • Practical examination: 10 points
  • Semester work: 30 points (15 Midterm + 15 labs)
  • Total: 100 points
• To pass, a student must achieve at least 50% overall, comprised of 50% of the grade.
• At least 30% must come from the final written exam.

Chapter 1: The Systems Development Environment Objectives

• Defining systems analysis and design requires the ability to gather, organize, and interpret information for business success.
• Systems analysis and design is a methodology helping businesses utilize information to its full capacity.
• The goal is to improve organizational systems by developing or acquiring application software and training employees in their use.
• Application Software/system supports organizational functions, for example, inventory management, payroll, or market analysis.
• The objective of application software is turning data into information.

System

• A system transforms data into information.
• "A system is an interrelated set of business procedures (or components) used within one business unit, working together for some purpose."
• A system exists within a larger world, which is its environment.
• A boundary separates a system from its environment.
• Systems take input from outside, system processes inputs to send back as output into its environment.
• A system has seven characteristics.

Characteristics of a System Explained

• Components: Parts that make up a system (also called a subsystem).
• Interrelated Components: Dependence of one part of the system on one or more other system parts; for example, customer daily report & customer orders.
• Boundary: A line separates the inside and outside of a system from its environment and other systems.
• Purpose: The overall goal or function of a system; the system's reason for existing.
• Environment: Everything external to a system's boundary that interacts with the system.
• Interfaces: The point of contact where a system meets its environment or where subsystems meet each other.
• Constraints: Limits to what a system can accomplish in terms of capacity, speed, or capabilities.
• Input: What a system takes from its environment to function.
• Output: What a system returns to its environment as a result of its functioning, achieving its purpose.

System Concepts

• Systems analysts should know systems concepts to understand their function:
• Decomposition
• Modularity
• Coupling
• Cohesion (unity)

System Concepts: Decomposition

• Decomposition: Breaking down a system into smaller components.
• It allows the systems analyst to:
  • Break a system into small, manageable and understandable subsystems
  • Focus attention on one area (subsystem) at a time
  • Concentrate on the part of the system pertinent to the particular group of users, without confusing users with unnecessary details.
  • Build different components at independent times

System Concepts: Modularity

• Modularity: A result of decomposition, dividing a system into chunks or modules of uniform size.
• Modules simplify system representation, ease understanding, and redesign/rebuild.

System Concepts: Coupling

• Coupling is the degree of interdependence between systems or modules.
• Subsystems should be as independent as possible.
• Subsystems function best independently.
• Highly dependent subsystems risk failure if one fails.
• Good designs have low coupling.
• Coupling is measured by the number of relations between modules.

System Concepts: Cohesion

• Cohesion: How closely activities within a single module are related.
• A highly cohesive module performs one task/objective; applying one single task is better.
• Low coupling and high cohesion are competing factors.
• A developer needs to balance coupling and cohesion.

Role in Systems Development: System Analyst

• The system analyst is responsible for systems analysis and design.
• The system analyst role involves:
  • Studying problems and needs within organizations
  • Helping users and managers define requirements for new or enhanced information services
  • Analyzing problems by observing data and facts about operating businesses
  • Drawing specifications and assigning relevant responsibilities to team members
  • Designing and evaluating systems to ensure they meet specifications
  • Staying updated with technological advancements; being agents of technological change

Skills of a Successful Systems Analyst

• Required Skills: analytical, technical, managerial, and interpersonal.
• Analytical Skills:
  • Understanding organizations
  • Problem-solving skills
  • System thinking
  • Seeing organizations and information systems as systems
• Technical Skills:
  • Understanding technology potentials and limitations
  • Proficiency in programming languages (C++, Java) and operating systems
• Managerial Skills:
  • Ability to manage projects, resources, risk, and change
• Interpersonal Skills:
  • Ability to work with end users, analysts, and programmers
  • Effective written and oral communication, meeting leadership, interviewing, and listening

Developing Information Systems

• Like commercial products (e.g., a Honda car), information systems follow a life cycle: created, tested, introduced, sales increase/peak/decline, and eventual replacement.
• Organizations use a standard set of steps, called a systems development methodology, to develop and support their information systems.

Systems Development

• Systems development methodology is the step-by-step process to analyze, design, implement, and maintain information systems.
• The development of information systems often follows a life cycle called the systems development life cycle (SDLC).
• SDLC: A "series of steps used to manage the phases of development for an information system."

Systems Development Life Cycle SDLC

• SDLC steps:
  • Phase 1: Systems Planning and Selection
  • Phase 2: Systems Analysis
  • Phase 3: Systems Design
  • Phase 4: Systems Implementation
• SDLC Phases are not necessarily sequential.
• The life cycle can be sequential (waterfall model) or involve parallel activities.
• SDLC phases can also be iterative (Agile approach) and/or a spiral approach.
• Each phase of SDLC has specific outcomes and deliverables.
• Individual companies customize the SDLC.

SDLC: Phase 1: Planning and Selection Phase

• Main activities:
  • Identifying the need for a new or enhanced system
  • Investigation and determination of scope

Products (Deliverables) for Systems Planning and Selection

• Priorities for systems and projects
• Architecture for data, networks, hardware, and IS management
• Detailed work plan for selected project
• Specification of system scope

SDLC: Phase 2: Systems Analysis Activities

• Preliminary investigation
• System survey: The study of the current system
• Determination of user requirements
• Analysis of the system survey
• Systems analysis report

Products (Deliverables) for Systems Analysis

• Description of current system
• General recommendation on how to fix, enhance, or replace the current system
• Explanation of alternative systems and justification for the chosen alternative
• System-requirements document

SDLC: Phase 3: Systems Design Phase

• Analysts convert the recommended alternative solution into logical and physical system specifications.
• All system aspects are designed, from input/output screens to reports, databases, and computer processes.
• Diagrams map the origin, flow, and processing of data, converting into a structured systems design broken down into smaller units for programming.

Products (Deliverables) in Systems Design

• Detailed specifications of all system elements.
• A system-design document is needed for programmers to create the system.

SDLC: Phase 4: Systems Implementation and Operation

• Systems are turned into a working system which is tested and put into use.
• Coding: Programmers write code to make up the system
• Testing: Programmers and analysts find and correct errors in programs/systems.
• and installation: The new system becomes a part of the daily activities of the organization.
• Application software is installed/loaded on existing/new hardware
• Documentation
• User training

SDLC: Phase 4: Systems Implementation and Operation - Operation Part

• Users may find problems and want improvements in the system.
• Programmers make changes to reflect user requests and changing business conditions.
• The time and effort for system enhancements depends on the life cycle phases.

SDLC: Phase 4: Systems Implementation and Operation (Maintenance)

• Operation and Maintenance includes fixing reported bugs.
• It also involves evaluating/implementing new feature requests.
• System updates and backups are performed routinely.

Products (Deliverables) of Implementation and Operation

• Code
• Documentation
• Releases and updates of software, including any updates to documentation training/support