M1 discuss the most appropriate uses of different development life-cycle models attempt 2

4:

A section that gives an example in business of each method type and why that model is most suitable

Waterfall and spiral lifecycles

Spiral

It is used in big development projects and in the stages there are arranged in the shape of a spiral, it is used when somebody wants to use a new technology

The spiral is also another software development process, it combines pieces of the waterfall model with the features of prototyping this model was developed to be used for large and complicated projects which will be expensive

The process of development will normally be closely tied to the waterfall model, both models having similar stages

The spiral model allows for you to keep adding improvements to the model unlike the water model which doesn’t allow for you to go back and change the model and since the spiral model is suited for big projects, a company is bound to make a mistake along the way and will need them to go back and correct any mistakes, this is why the waterfall model is no good for company which are big and are spending a lot of money.

But using the spiral model normally takes more time and it requires more resources then the waterfall model.

What kind of projects are they suitable for?

Projects which are large and will cost a lot of money and are very complicated the spiral model looks to be suited to the larger and more important tasks and is not suited for small projects. For example a multibillion pound company will need to use the spiral model because the projects are big and cost a lot of money and contain lots of important tasks

Waterfall

This lifecycle uses a sequential method of stages and they have a clear goal for each development stage when using this you cannot go back to the previous stage although this waterfall model is very easy to use. The system doesn’t allow you to go back, so if any changes need to be done to the system it is best being done at the beginning because it is hard to go back and make the required changes

The waterfall method is used for software development and contains several stages which is incorporated into the model, the several stages are, requirements specification, design, construction/implementation, integration, testing and debugging, installation, maintenance.

The waterfall diagram has clear goals for the different development stages and doesn’t allow you to skip the stages

The waterfall model should move to a phase only when it’s previous stage is completed and perfected if the stage is not complete then it will not allow the analyst to move on, the waterfall model allows the user to find problems with the system at the earlier stages and then they are able to be changed to allow the system to work.

When working with the waterfall model it’s hard to leave things out in the earlier stages, because the planning process is very accurate.

What kind of projects are they suitable for?

They are suitable to projects that have low risk in the areas of user interface and the performance requirements, but have a high risk in budget and schedule predictability and control.

M1 discuss the most appropriate uses of different development life-cycle models

Waterfall and spiral lifecycles

Spiral

It is used in big development projects and in the stages there are arranged in the shape of a spiral, it is used when somebody wants to use a new technology

The spiral is also another software development process, it combines pieces of the waterfall model with the features of prototyping this model was developed to be used for large and complicated projects which will be expensive

The process of development will normally be closely tied to the waterfall model, both models having similar stages

What kind of projects are they suitable for?

Projects which are large and will cost a lot of money and are very complicated the spiral model looks to be suited to the larger and more important tasks and is not suited for small projects.

Waterfall

This lifecycle uses a sequential method of stages and they have a clear goal for each development stage when using this you cannot go back to the previous stage although this waterfall model is very easy to use.

The waterfall method is used for software development and contains several stages, requirements specification, design, construction/implementation, integration, testing and debugging, installation, maintenance

The waterfall model should move to a phase only when it’s previous stage is completed and perfected

What kind of projects are they suitable for?

They are suitable to projects that have low risk in the areas of user interface and the performance requirements, but have a high risk in budget and schedule predictability and control

P2 illustrate the stages of a development life cycle

Initiation

This stage is a stage which reviews the current system in place; they look at the system and find out how it can be improved and then at the end of this stage there is a feasibility study report, and if that report is accepted then more advance research is carried out

Why is it required?

It’s required because if the programmers make a new system and add something which was in the old one then it’s not going to improve the current system, but if they looked at the current system they would know exactly what they have to do to improve the new system.

Investigation

This stage is all about fact finding and this involves defining the scope of the system; it investigates in detail on how the current system works.

This includes how the data is put into the system and how it flows around the system

Why is it required?

Because they need to know how the current system works if they are to improve the system, they will have to investigate in detail.

Analysis

When at the analysis stage it involves using a number of different techniques to model the flow of information and interrelationships in the system

Why is it required?

you need to know how the information flows around the system

Design

The design stage uses the information that was gathered and analysed in the previous two stages and then produces a detailed design, this will become a guide for the programmers who are going to be adding the system.

Why is it required?

Programmers need a design to follow, if there isn’t a design programmer’s will likely make mistakes while making it

Implementation

Why is it required?

Because if it wasn’t implemented then there would be no system so it’s important to implement it

Maintenance

Why is it required?

Because without regular maintenance the system could break down and possibly become unusable regular maintenance is required to keep the system updated and working correctly

Testing

Why is it required?

Testing the system is required to eliminate all bugs within the system doing this will make doing maintenance in the long run easier

The lifecycle model

The lifecycle model has no clear start or finish, it is useful to think that the start of the cycle as being the point where there is dissatisfaction with the existing system, it is a process of creating or altering information systems and the models and methodologies that people use to develop the systems

Every development process and the products life has a cycle with 7 stages it is called the lifecycle model because the cycle is always on going if a company is not making new products then the company is analysing their current products

P1 outline the principles of systems analysis

Key drivers

Need for Growth

The drivers are need for growth and many businesses need to expand into new markets they develop new products and also increase their turnover and profits for them to do this they have to plan effectively and they often will have to incorporates system analysis.

Need to increase productivity

The sales may have improved but there is also a need to improve capacity, also the activity of the competitors may require that the company their ability to respond

The more employers that are working on the system means that it may slow it down or cause a expansion in terms of physical space of multiple sites

Reduce costs

To reduce the costs they need to be more efficient and improve the turnover ratio especially in times of economic recession

A company may need to makes their systems less labour intensive or costly they can do this by saving money.

Developmental tools

They are things like data flow diagrams and activity diagrams

What are data flow diagrams?

A data flow diagram (DFD) is a graphical representation of the flow of data through an information system

A preliminary step used to create an overview of the system which can be elaborated

What are activity diagrams?

An activity diagram is graphical representation of workflows

They can be used to describe the business and operational step by step workflows of components in a system; an activity diagram shows the overall flow of control in a system

Techniques of systems analysis

How to gather all the information, you could do surveys or interviews in order to collect the information needed surveys are a good source of information but you are unable to expand your questions depending on the persons answer with an interview you can expand on your questions if needed so you gather more information.