Modern Systems Analysis and Design Chapter 1 Part 2

Phases of the SDLC (1 of 3) • Planning – – – – Need for a new or enhanced system is identified Needs are identified, analyzed, prioritized, and arranged Determine the scope of the proposed system Baseline project plan is developed • Analysis – System requirements are studied from user input and structured – Requires careful study of current systems, manual and computerized, that might be replaced or be enhanced – Output is description of the alternate solution recommend by the analysis team Phases of the SDLC (2 of 3) • Design – Analyst converts the alternate solution into logical and physical specifications – Logical Design ▪ The design process part that is independent of any specific hardware or software platform – Physical Design ▪ The logical specifications of the system from logical design are transformed into technology-specific details from which all programing/system construction can be accomplished – Choices of language, database, and platform are many times already decided by the organization or client Phases of the SDLC (3 of 3) • Implementation – Occurs when the information system is coded, tested, installed, and supported in the organization – New systems become part of the daily activities of the organization • Maintenance – The phase in which an information system is systematically repaired and improved – Organization’s needs may change over time requiring changes to the system based on user’s needs Table 1-1: Products of SDLC Phases Phase Products, Outputs, or Deliverables Planning • • • • • Analysis • • Design • Priorities for system and projects; an architecture for data, networks, and selection hardware, and information systems management are the result of associated systems Detailed steps, or work plan, for project Specification of system scope and planning and high-level system requirements or features Assignment of team members and other resources System justification or business case Description of current system and where problems or opportunities exist, with a general recommendation on how to fix, enhance, or replace current system Explanation of alternative systems and justification for chosen alternative • Functional, detailed specifications of system elements (data, processes, inputs, and outputs) Technical, detailed specifications of all system elements (programs, files, network, system software, etc.) Acquisition plan for new technology Implementation • Code, documentation, training procedures, and support capabilities Maintenance • New versions or releases of software with associated updates to documentation, training, and support • Figure 1-6: Heart of systems development • The location of activities and the specific sequencing of steps can vary greatly from one project to the next • Current practice combines analysis, design, and implementation into a single process • The process is also called the analysis–design–code–test loop Figure 1-7: Traditional waterfall SDLC • Once one phase ends another begins • Process goes downhill until complete (i.e., waterfalls from one to the next) • Makes it difficult to go back • Great expense to make changes • Role of system users or customers narrowly defined • Focused on deadlines Agile Methodologies (1 of 2) • Methodologies adapted from engineering generally do not fit with real-world software development • Agile methodologies share three key principles: 1. A focus on adaptive rather than predictive methodologies 2. A focus on people rather than roles 3. A focus on self-adaptive processes Agile Methodologies (2 of 2) • Agile methodologies are not for every project • Fowler recommends an agile process if your project involves – unpredictable or dynamic requirements – responsible and motivated developers – customers who understand the process and will get involved