Principles Of Systems Analysis Information Technology Essay

Principles Of Systems Analysis Information Technology Essay This assignment will discuss the principles of systems analysis and then two different methodologies used in the systems analysis process when designing computer systems. It will highlight the advantages and disadvantages of the two methodologies. It will also show which method is the most appropriate for the case study. Finally it will also show a PowerPoint presentation of key drivers which force business organisation to invest in a new computer system. P1- Principles of Systems Analysis Development life cycles Development life cycle models identify the stages to which processes must be carried out in order to develop a successful system. Depending on the type of business that are requiring the new system, and the type of system they are hoping to have by the end, accounts for the type of model chosen to be used in order to build the system. Types of development life cycles include: waterfall model, rapid applications design (RAD), spiral model, the systems analysis and design (SAD), dynamic systems development methodology (DSDM) Development life cycles have different stages. For example, Development methodologies Methodologies are a way of structuring the development process of a computer system. They are the framework which is followed in order to make a system successful. Tools and techniques that can be used in order to develop a system include: Data flow diagrams: these outline the processes which happen between the business and its clients or customers, external systems and external organisations in order to identify the activities which will be taking place within the system along with the information which will be flowing within the system. CASE Tools: computer aided software engineering (CASE) tools aim to support the diagram designs and to make checks and changes where required. CASE tools have different uses. These include: diagram validation, diagram creation as well as report and code generating. Key drivers Key drivers force businesses to invest in a new computer system in order to improve or upgrade their current one. Some examples of key drivers include: the computers being too old, the current system no longer meeting government requirements, close competitors having better systems, the need for improved efficiency, or the business wanting to grow and expand. P2- Methodologies The waterfall model The waterfall model is a systems development cycle which identifies each stage the development of a system must go through. Initiation and planning Investigation Analysis Design Implementation Testing Maintenance Initiation and planning- is where all the businesses needs are taken into account as well as reviewing the current system to decide what exactly needs to be done to the system. If the initiation and planning stage is not carried out, it likely that the project will be unsuccessful. Investigation- this is the stage where the final decision is made about what exactly needs to be done to the system where factors such as budget and time are taken into consideration. Analysis- this is the stage where all the data needed to create or modify the system is collected. An initial idea is also considered and is sometimes tried out in order to see if there is a possibility of it working before the actual designing of the new system takes place. Design this stage works alongside the analysis to decide upon the best way to either create or modify the system. Here is where ideas are identified that was not noticed before, and others can be crossed off as not possible. Implementation all the work required to create the new system are separated into units. The software is the engineered by being written and coded so that the system can understand, before being debugged and the process of troubleshooting takes place. Testing this is the stage where each unit is trialled to see that it works with the other units as well as ensuring that the new system meets the specification originally set. Maintenance This is the stage which comes into sight only after the system is up and running. Some problems only occur once the system starts being practically used so during the maintenance stage, errors which have been found are corrected and the system can be modified accurately to fulfil its requirements. Also, the system can be constantly maintained so as not to need a brand new one, but can be updated in order to improve the systems efficiency when it starts to decline. P3- Advantages: Each stage can be given a deadline to be completed allowing the business knowing exactly when their system will be completed. Each stage is clear and they do not overlap making tasks that need to be carried out clear. This order ensures things are not left out, forgotten or left unfinished Disadvantages: Once the development has moved on from one stage from the next, it is difficult to go back and make amendments due to the waterfall model not being flexible. All specifications need to be made at the beginning, once the designing begins, changes cannot be made meaning once the client has submitted their request, they cannot build on or adapt it. P2- Rapid Applications Development (RAD) Like the waterfall model, the rapid applications development model is a model which identifies stages in which system goes through in order to be effectively developed. However, it is a more flexible development model compared with the waterfall model. Prototype Test Assess Design Design this is where the specification for the new system is made and an image can be drawn up of what is expected of the new system. Vitalities for the new system are taken into account and the professional work alongside the business to design a system to match all of the businesses requirements. Prototype a scaled down system is created and trialled in order to represent what the final finished system will be like. This helps to identify any minor adjustments that need to be made before the new, final system is put in place. These are usually built on and used in the final system helping to speed up the development of the new system. Test the system is tested to ensure everything works as it should as well as making sure all the requirements have been met and nothing was left out or forgotten. This is important as some things arent clear until the system is finished and starts being used for its purpose. Assess this is the stage where it is decided whether the system is fully suitable for use or whether it requires some modifications and more designing before it is completely ready to fulfil the purposes to which the business requires of it. P3- Advantages: The RAD Model is adaptable to changes and is fairly flexible The prototype stage allows a clear insight into what the final system will be like and allows changes to be made before the system is finalised The system development using the RAD model is generally quite short. There is a strong success rate due to the number of times the product is reviewed before it is made final. Reusing the created prototypes helps to reduce project cost and so keeping the budget low Disadvantages: Due to being created for just one particular need, if later on it is decided that the system needs to be expanded further or made bigger, it is difficult due to only being created specifically for a sole purpose. Is most successful when being used to build upon a current system. It is not ideal for larger businesses and projects I think that for in the case of the Selchester Hotel, it would best for them to use the Rapid Applications Development model rather than the Waterfall model. This is because it is more cost effective due to being able to build upon the current system rather than having to begin from scratch which also makes RAD a much quicker development model to use. The hotel is in constant demand of its clients and so cannot have its system unavailable for long periods of time. Also, although generally the RAD model isnt ideal for larger businesses, it allows adaptations to be made later on in the development which could be vital due to the hotel gaining or losing competition and so needing to enhance their systems to cope with their new circumstances. Finally, having prototypes created allows the hotel to be confident that their new system will be successful before it is finished and to be able to see what the final system will be like.