Mumbai University > Computer Engineering > Sem 5 > Structured and Object Oriented Analysis & Design

Marks: 10M

Year: May 2015, May 2016

Systems Development Life Cycle (SDLC)

1. The systems development life cycle (SDLC) is the process of determining how an information system (IS) can support business needs, designing the system, building it, and delivering it to users.
2. The systems development life cycle (SDLC), also referred to as the application development life-cycle, is a term used in systems engineering, information systems and software engineering to describe a process for planning, creating, testing, and deploying an information system.

Phases of SDLC:

1. System Planning

   The planning phase is the fundamental process of understanding why an information system should be built and determining how the project team will go about building it. It has two steps:

• During project initiation, the system's business value to the organization is identified how will it lower costs or increase revenues? Most ideas for new systems come from outside the IS area (from the marketing department, accounting department, etc.) in the form of a system request. A system request presents a brief summary of a business need, and it explains how a system that supports the need will create business value.
• Once the project is approved, it enters project management. During project management, the project manager creates a work plan, staffs the project, and puts techniques in place to help the project team control and direct the project through the entire SDLC.

1. System Analysis

   The analysis phase answers the questions of who will use the system, what the system will do, and where and when it will be used. During this phase, the project team investigates any current system(s), identifies improvement. This phase has three steps:

2. An analysis strategy is developed to guide the project team's efforts. Such a strategy usually includes a study of the current system (called the as-is system) and its problems, and envisioning ways to design a new system (called the to-be system).
3. The next step is requirements gathering (e.g., through interviews, group work-shops, or questionnaires). The analysis of this information—in conjunction with input from the project sponsor and many other people—leads to the development of a concept for a new system.

4. The analyses, system concept, and models are combined into a document called the system proposal, which is presented to the project sponsor and other key decision makers (e.g., members of the approval committee) who will decide whether the project should continue to move forward.

5. System Design

   The design phase comes after a good understanding of customer’s requirements, this phase defines the elements of a system, the components, the security level, modules, architecture and the different interfaces and type of data that goes through the system. The design phase decides how the system will operate in terms of the hardware, software, and network infrastructure that will be in place; the user interface, forms, and reports that will be used; and the specific programs, databases, and files that will be needed. The design phase has four steps:

• The design strategy must be determined. This clarifies whether the system will be developed by the company's own programmers, whether its development will be outsourced to another firm (usually a consulting firm), or whether the company will buy an existing software package.
• This leads to the development of the basic architecture design for the system that describes the hardware, software, and network infrastructure that will be used.
• The database and file specifications are developed. These define exactly what data will be stored and where they will be stored.
• The analyst team develops the program design, which defines the programs that need to be written and exactly what each program will do.

1. Implementation and Deployment

   This phase comes after a complete understanding of system requirements and specifications, it’s the actual construction process after having a complete and illustrated design for the requested system.

   In the Software Development Life Cycle, the actual code is written here, and if the system contains hardware, then the implementation phase will contain configuration and fine-tuning for the hardware to meet certain requirements and functions.

   In this phase, the system is ready to be deployed and installed in customer’s premises, ready to become running, live and productive, training may be required for end users to make sure they know how to use the system and to get familiar with it, the implementation phase may take a long time and that depends on the complexity of the system and the solution it presents.

2. System Testing and Integration

   Bringing different components and subsystems together to create the whole integrated system, and then introducing the system to different inputs to obtain and analyze its outputs and behavior and the way it functions. Testing is becoming more and more important to ensure customer’s satisfaction, and it requires no knowledge in coding, hardware configuration or design.

   Testing can be performed by real users, or by a team of specialized personnel, it can also be systematic and automated to ensure that the actual outcomes are compared and equal to the predicted and desired outcomes.

3. System Maintenance

   In this phase, periodic maintenance for the system will be carried out to make sure that the system won’t become obsolete, this will include replacing the old hardware and continuously evaluating system’s performance, it also includes providing latest updates for certain components to make sure it meets the right standards and the latest technologies to face current security threats.

   These are the main six phases of the System Development Life Cycle, and it’s an iterative process for each project.