Lifecycle Models, Research Paper Example

The prototype model

The Prototype Model, as illustrated in Fig 1, is a reduced functionality model that enables the systems developer to build the early stages of a systems development project. The concept being to build a scaled down version of the real systems development in order to test functionality and operability. If built correctly this can save the systems developer significant amounts of time. Prototypes can be quickly assembled and thrown away, going through a repetitive cycle until the right solution is found. (Langer, A.M. 2007).

Figure 1 The Prototype Model

Advantages

• Rapid Application development capability
• Economies of Scale
• Repetitive process, facilitating correct solution
• Throw away concept

Disadvantages

• Some argue that it involves additional unnecessary costs
• The concept of a ‘quick and dirty’ method that lacks sophistication
• Developer may make compromises to determine fast expedient solution that lacks quality requirements.

Rapid application development model

This method is based upon a linear application development approach. RAD is used for high speed technology build process. The approach is based upon providing the basic system functionality without the development of unnecessary “bells and whistles”.  This provides a rapid cost effective no frills approach to systems development work.  Fig 2 illustrates the cyclical events of RAD application development. (Shelly, G.B  2009)

Figure 2:  Rapid Application Development Model

Advantages

• Optimum business systems solution
• No unnecessary frills keeping development costs to a minimum
• Supports most business modelling approaches
• Supports Data Modelling
• Very cost effective
• Component based construction approach

Disadvantages

• Provides minimum solution to requirements. No value added components
• May represent only a partial not full systems solution
• Prone to developers taking short-cut measures
• Needs to be fit for purpose

V-Model

One of the most widely accepted systems development models.  Provides a number of discrete phases within a systems lifecycle development context. Based upon a number of discrete components that include: Requirements Analysis, System Design, Architecture Design, Module Design and Coding. This method approach is extremely thorough and facilitates sign off and approval on each stage before proceeding to the next stage. (Wasson, C.S. 2006)

Advantages

• Completeness – structured systems development lifecycle model build
• Preview each stage and approve content
• Integrated systems development and design concept
• Testing is early saving time and effort
• Reduces costs of defects as these are discovered in early stages of development
• Rapid application development method

Disadvantages

• Extremely rigid approach and lack flexibility in development and design process
• It is more suitable to large scale systems applications
• Processes need to be established in order that the method can implement them

The systems lifecycle model

The Information Systems Lifecycle is essentially a cascade approach towards the development of an information system, Fig 4 refers.  It essentially consists of four main phases of development i.e. (1) Analysis (2) Design (3) Construction and Implementation ( 4) Review and Maintenance.  These are further split down into a number of sequential steps that help in defining the logical from the physical components of the system build process.

Illustration Case Study Approach | Small Photography business

In developing the requirements for a new computer time entry system, the following lifecycle steps would take place:

Analysis |  Feasibility Study | Examination of alternative approaches, together with cost/benefit analysis. Might consider three options (1) Re-engineering of existing system, (2) New custom build software approach  (3) A Custom off the shelf package

Analysis | Requirements Analysis – Complete a functional specification of requirements

Design | Complete the logical and physical design of the system

Implementation |  Develop the code for the system, complete user, module and integration testing, convert and implement the system

Review and Maintenance – Go live and put the system into a maintenance environment for fixes, new releases and updates.

Future Trends in Lifecycle Modelling

Future trends are moving more towards open architecture and concepts of cloud computing.  Cloud computing seems to offer a number of significant advantages to the CIO. This approach is particularly attractive to the small-medium sized business that has limited funds to invest on more expensive IT infrastructure and equipment.

Fig 5 Illustrates the concept of cloud computing. It permits the user to gain access to the firm’s information via a wide range of portable computer devices including that of smart phones, tablets, laptops, notebooks etc.  This brings the whole range of the business applications to your portable PC via a wireless or other internet connection.  It is the ultimate portability concept for the travelling Executive. The migration however involves a number of serious business considerations.  The two prime risks are the loss of control and security over the firm’s private data (information) and the lack of transparency from the Cloud hosting service provider in terms of storing and processing your data (Kshetri, 2011)

References

Gary B. Shelly, H. J. (2009). Systems Analysis and Design (8 ed.). New York: Cengage Learning.

Kay, R. (2012, 2 3). QuickStudy: System Development Life Cycle. Retrieved from Computerworld: http://www.computerworld.com/s/article/71151/System_Development_Life_Cycle

Kshetri, N. (2011). Privacy and security issues in cloud computing. Greensboro, USA: University of North Carolina.

Langer, A. M. (2007). Analysis and Design of Information Systems. New York: Springer.

Microsoft Corporation. (2012, 2 12). Testing Methodologies. Retrieved from Microsoft Corporation: http://msdn.microsoft.com/en-us/library/ff649520.aspx

University at Albany / SUNY. (2012, 2 3). A Survey of System Development. Retrieved from University at Albany: http://www.ctg.albany.edu/publications/reports/survey_of_sysdev/survey_of_sysdev.pdf

Wasson, C. S. (2006). System Analysis, Design, and Development: Concepts, Principles, and Practices. New York: John Wiley & Sons.