Stages of the Development Life Cycle - P1 and P2

The development life cycle represents the life of a system. These systems will need to be:

•Designed

•Monitored

•Updated 

•Replaced all over a period of time.

•There are 5 stages in the development life cycle, they are as follows:

Stage 1: Analysis

Activities/processes that are carried out in this stage are:

•Problem statement - A report that highlights any potential issues that could occur during the analysis and design of the systems.

•Interview with the users - The interviews are held with the users to determine whether they are willing to use the systems, are they experienced enough or would they need training etc.

•Feasibility study - The people conducting the analysis look at the possibility of the project that they are working on. For example, checking the resources that are available to them (is the budget big enough?, do they have enough staff/time?)

Stage 2: Design

Activities/processes that are carried out in this stage are:

•Process description - Accurate and detailed explanations of every process that is going to be occurring in the new system. For example, database software that will be used for keeping records.

•Data flow diagrams - These provide a visual representation of the data flow travelling through a system. This allows a user to get a much better understanding on the processes that occur in  a system.

•Data dictionary - Is a set of information that describes the content, functions and structure of a system.

Stage 3: Implementation

Activities/processes that are carried out in this stage are:

•Program coding - In this stage, the actual installation of the system begins. The actual coding of programs/applications will take place, using assets that have already been produced (data dictionary, data flow diagrams etc.)

•Migration of data - Means to transfer all the information from the original system over to the one that is being put in place.

•Training the users - Once this has all been done, the users would need sufficient training in how to use these systems, based on the interviews that were held earlier on the amount of time needed to train them may vary depending on how inexperienced the users are with these systems.

Stage 4: Testing

Activities/processes that are carried out in this stage are:

•Data testing - Refers to the testing of the information stored on the system (for example, programs that have been installed onto the system, do they work? Is it suitable for the user to use? Has all the data been transferred to the new system? Etc.)

•Compatibility checks - Are done to make sure that all the information/programs/applications that have been installed onto the system can work properly on said system. As well as tests to make sure that the user is able to work with the system (is it user friendly? Are there any bugs in the system preventing them from being able to use it? Etc.)

•Verification - The system has to be verified that is 100% functional, is safe for users to begin using, can support all the desired information etc.

Stage 5: Evaluation

Activities/processes that are carried out in this stage are:

•Reviews - Once the system has been fully set up and declared available for use, a review/reviews need to be conducted in order to reflect on how the design and analysis of the system went. Was the budget big enough to support the project? Were there enough resources? Did we meet all the goals for the project? How closely were the steps of the development life cycle followed?

•Performance monitoring - The performance of the system will then be monitored for a period of time after the user has began to work with it. This is to make sure that they have received sufficient training in the use of the system, as well as to check if any issues/errors crop up after the initial setup has taken place.

•Amendments - If there are any problems detected in the performance monitoring, amendments will need to be done in order to make sure that these issues are fixed and are unlikely to occur again. Think of it as regular updates being applied to the system.

Tools that can be used for Systems Analysis

A data flow diagram is used as a representation of the data flow through a system. These allow someone to see a process in the system from the viewpoint of the data, as well as offering a visual representation of how a system operates, what it accomplishes and how it will be implemented.

There are 4 components in a DFD, these are represented by 4 symbols:

•External entities – The source/destination of the data. Represented by squares.

•Processes – Such as input/processing/output, these are represented by rectangles with rounded corners.

•Data flow – Whether physical or electronic data, this is represented by an arrow.

•Data stores – Physical/electronic data stores are represented by open-ended rectangles.

CASE (stands for Computer Aided Software Engineering) this is the use of computer based design tools to help develop systems. By utilising these tools, analysts are able to increase productivity and improve the quality of the pre-existing systems as well as the new systems that are being designed.

SSADM stands for Structured Systems Analysis and Design Method. This is an industry standard that is developed for systems analysis in many government run projects. SSADM combines both text and diagrams throughout the entire design stage in the development life cycle, from the initial design idea of the system to the systems’ physical design.

Many government run projects use SSADM because they believe that, through the use of a professional, engineering tool, they will be able to improve the overall quality of the systems that they are designing.

There are 7 steps to SSADM. These are as follows:

Feasibility study – Is it possible to achieve what we want?

Investigation of the current system – What needs to be improved in our design?

Business systems operations – Does our organisation have the resources needed to support this?

Requirements specification – Do we have everything that we need to design these systems?

Technical systems operations – Can we operate these systems?

Logical design – Do we have a theoretical design that we want to use?

Physical design – Does our physical design match the theoretical one and does it meet our requirements?

  

Key Drivers

Key drivers are reasons that can initiate the systems analysis and can eventually lead to the design of new systems. These key drivers are:

Need for growth - Expansion of the business (for example, developing online sales, moving into a larger work environment or expanding what the business does.)

Company acquisition - Taking control of another business.

Increase in productivity - Introducing new ways of improving the efficiency of the business (for example, setting up faster systems that require little human interaction to operate.)

Legal requirements - Meaning that, by law a new system would have to be implemented. For example, e-commerce actions require an email as acknowledgement of an order.

Development Life Cycle Models

These are models of systems analysis that closely follow the stages of the development life cycle. They all vary in their approach to systems analysis, and some are more appropriate in certain situations than others. We will be covering three of the most widely used models.

Waterfall Model – Used for projects that are short and easy, (the requirements are understood by the user.) The phases of this stage do not overlap (one must be completed before the next one can begin.) After the end of each stage a review takes place to determine whether or not the project is on the right track.

Rapid Applications Development (RAD) – Used to quickly develop systems for low cost. In this model every phase is developed in parallel with each other (as though they were all smaller projects.) This reduces the development time as all the phases are completed at the same time. Feedback from the users is encouraged.

Spiral Model – Used for complex projects with a high risk and cost attached to them. While the risk of failure of the project is high, a large amount of risk analysis takes place in order to try and reduce that risk. The software is developed very early on in the model, allowing for additional functionality to be added later.