System Development Life Cycle

In systems engineering, information systems and software engineering, the Systems Development Life Cycle (SDLC), also referred to as the application development life-cycle, is a process for planning, creating, testing, and deploying an information system.

The concept of the systems development life cycle applies on hardware, software and a combination of both. The system can be build with the help of hardware only, software only, or a combination of hardware and software.

Software Development Life Cycle (SDLC) is a process used by the software developer to design, develop, and test high-quality software. The SDLC aims to produce high-quality software that meets customer expectations, reaches completion within times and cost estimates.

Why SDLC is important for developing a software system?

1. provides a basis for project planning, scheduling, and cost estimating
2. provides a framework for a standard set of activities.
3. provides a mechanism for project development/ tracking and control along with project planning.

Software Development Life Cycle is a process that composed of a number of clearly defined and distinct work phases that are used by an information technology resource, such as systems engineering and system developers to plan for design, build, test, and deliver information systems.

In many ways, building an information system is similar to building a hospital. First, the hospital (or the information system) starts with a basic idea. Second, this idea is transformed into a simple drawing that is shown to the customer (owner of the hospital) and refined (often through several drawings, each improving on the other) until the customer agrees that the picture depicts what the owner of the hospital wants (customer).

Third, a set of blueprints is designed that presents much more detailed information about the hospital (e.g. the type of water faucets, where the telephone jacks will be placed). Finally, the hospital is built following the blueprints and often with some changes and decisions made by the customer as the hospital is erected. 

Similarly, when developing information systems, most organizations use a standard of steps called the systems development life cycle (SDLC) at the common methodology for system development. SDLC has a similar set of four fundamental phases : 

1. System Planning

2. System Analysis

3. System Design

4. System Implementation,

Different projects may emphasize different parts of the SDLC or approach the SDLC phases in different ways, but all projects have elements of these four phases. Each phase is itself composed of a series of steps, which rely on techniques that produce deliverables (specific documents and files that provide understanding about the project).