How to Understand the Software Development Lifecycle (SDLC)

The recent years have brought advances in information technologies that in turn have increased the size and complexity of information systems. These same systems that were once designed, created and managed by one or more programmers, now require a more manageable process. The Systems Development Life Cycle and its traditional waterfall model set the tone for effective large-scale system development. The SDLC utilizes a five-phase, sequential process to take a system idea from planning to implementation/maintenance. The creation of this development process has led to many advantages with few drawbacks and limitations.

The first phase of the SDLC is systems planning. The phase begins with the systems request which presents the problem or change relative to an information system with the business. Requests can vary from major (creation of new system) to minor (adjustment or feature modification) and are prerequisite to the launch of any further work. If the request is valid, the organization will utilize a preliminary investigation which will determine what exactly needs attention. Involved in this investigation is a feasibility study that reviews and anticipates the various factors that will be affected by this proposed change (Cashman, Rosenblatt & Shelly, 2006).

After the preliminary investigation is conducted and it is ruled feasible to continue forward with the proposal, the second phase begins - systems analysis. This is where the logical model of the new system is created. The idea is to logistically formalize the requirements of this system through requirements modeling. This process utilizes various methods of fact finding to gather information and document what the new system must do (Cashman, Rosenblatt & Shelly, 2006). In the end, analysts will have created a systems requirement document that outlines the collected data, describes requirements and discusses development strategy.

In the third phase, systems design, the actual blueprint that reflects the necessary requirements outlined in the analysis phase is created. An important part of this phase is the application architecture. This helps to translate the logical structure into programmable code that will be used for implementation (Cashman, Rosenblatt & Shelly, 2006). The design includes the system interface and all necessary controls. The design is presented to management in the system design specification for approval and implementation.

The fourth phase, systems implementation, involves the installation and testing of the new system. Programmers work to create the necessary code and test the implemented functions. When finished the system is fully functional, documented and ready to use. This phase may conclude with an evaluation to determine if the system functions appropriately within expectations (Cashman, Rosenblatt & Shelly, 2006).

The final phase of the SDLC involves systems operation, support and security. This involves the general maintenance and security a system would need in the time after implementation. Now that the system is in place, it is important to ensure its efficiency and reliability. The organization wants to get the most out of the new system and a flexible well-maintained system allows for that. Flexibility is sometimes referred to as scalability. The system must be readily adaptable to the ever changing needs of the business.

Utilizing the Systems Development Life Cycle boasts several advantages compared to previous development methods. Traditionally, the waterfall model was first used, offering a sequential step-by-step process for development. This was a substantial upgrade in organization from previous processes. It allowed large systems to be developed by creating phases that were pre-requisites for advancement. More complex systems could be handled with the introduction of separate planning, analysis and design phases. This ensured a more efficient and reliable end product.

The SDLC and the waterfall model did have certain limitations however. Much of it was reliant on the ability to determine all requirements beforehand. This put a great deal of pressure on anticipation and it was necessary to handle steps with caution and precision. Also, the SDLC downplayed user involvement in its phases. The introduction of other models to the SDLC allowed for more flexibility and in many cases, time efficiency. Newer models such as rapid application development (RAD) focused on constant interaction between the planning, analysis and design phases. User input was incorporated and these phases functioned more as a back and forth than a sequence. This allowed requirements to be adjusted and obtained with greater ease. The designer did not need to perfect an entire phase before moving on. The availability of these different models of the SDLC has allowed organizations to select the most appropriate method in relation to their business needs. This gave them the most productive end product possible.

The SDLC and its five-phase process introduced a new level of efficiency in systems design. With the ever changing complexity of information systems the demand for a more efficient process was high. The Systems Development Life Cycle served as an important tool to this new trend. The flexibility of the SDLC models has allowed for businesses to cater to their development needs and produce systems that are both efficient and reliable.

References

Cashman, Rosenblatt & Shelly. 2006. Systems Analysis and Design. Boston, MA:
Thompson Course Technology.