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Unit 11 Systems Analysis And Design - Assignment 1
Transcript of Unit 11 Systems Analysis And Design - Assignment 1
Benefits of using structured analysis for software design.
Six stages of software development
Image by Tom Mooring
Unit 11 Assignment 1
The waterfall method works by completing one phase and then moving onto the next. A review takes place at the end of each phase to determine whether or not to move onto the next.
This methodology is used as it is very simple to follow and it allows for deadlines to be set more easily, however this methodology doesn't easily allow for change as it moves onto the next step when one step has been completed.
Systems analysis and design is where a systems analyst analyzes a business system, identifies any issues that are present and then provides a solution to these problems. In other words, he/she looks at a system and then makes it better.
The analyst would first need to gather information about the old system. The analyst would look at the system themselves of course, but the best way of evaluating the system would be to ask the people who use it regularly, the businesses employees. Via questionnaires, interviews or from shadowing them, the analyst would gather the information they need in order to identify any problems. Once this is done, he would need to ask what the customer and their employees want from the system.
Then the analyst would receive suggestions from the customer, or they might make suggestions themselves until the best solution has been chosen, one that is both accepted by the customer and the one that is practically the best.
Now the analyst would plan out the system using a variety of different tools to model and structure the system such as the six stages and the waterfall or the spiral methodologies. The data flow would be illustrated in data flow diagrams to show how the data will move through the new system, and eventually the new system will be created.
There will be a few key drivers present throughout this process. When creating a new system for a business, the key drivers would be creating an efficient system, one that is easy to use and one that provides all of the features necessary for it to serve its purpose.
Business key drivers include things such as the need for growth, company acquisition, to increase productivity and legal reasons.
Three examples of development lifecycles.
There are many benefits of using structured analysis when designing and developing software, and here are some examples.
When structured analysis is used, it allows for deadlines to be met due to the fact that the whole process has been planned extensively, so the time required to complete each section will be more accurately estimated. This also helps to reduce the risk of the project running over budget, another benefit of SAaD.
Projects will also be more manageable as it will have been arranged into sections, so each section can be completed at a time, or maybe each section will be assigned to a different person or group.
SAaD will also make sure that the system created will be well built and designed as the whole process is efficient and streamlined, ensuring that any mistakes will have been noticed and corrected and all of the user requirements will have been implemented.
This is the first stage and is where the user specifies what they want from the software, i.e what they want it to do.
A list of requirements will be drawn up, and will include essential and desirable requirements that the customer wants included in the software.
The user requirements gathered in this first planning stage form the basic outline of the whole project.
Once the software has been launched the development team will still have to be available to rectify any problems that may arise. Despite the testing stage, bugs and glitches may still be present, or new ones may arise. This can be because of a number of things, one example being an update to an operating system that may effect the software. These glitches or bugs will have to be rectified via updates and patches to make sure the software runs properly.
This is where the visuals of the systems are looked at and where the GUI's and screens are designed. The functionality of the software will also have to be shown here e.g. how information is input, how data is stored etc.
All of this can be shown via flowcharts or hand drawn designs so that the customer and the developers can see what the end result is likely to be, which ensures that A, everyone knows what they are working towards and B, the customer is happy with how the software will look and function.
This is where the software is actually coded by the programmer or programmers, depending on the size of the project.
All of the features and functions of the software will be coded so that they actually work properly and efficiently, and the software will begin to function as designed.
Programmers will likely test things as they work through the project, making sure that everything is functioning correctly after every section has been competed. This is ideal, but the software should also be tested by outside sources, making sure that there is no bias (this can happen unintentionally) when testing. Something might make sense to the person/people who have programmed or designed it, but it may not make sense or work for someone who has not worked on it.
There will be an in house (usually) Alpha testing phase and then an outside Beta testing stage making sure that the software has been tested as thoroughly as possible.
This stage is where the project manager will have a document drawn up which will include many things. It will contain details on how many people will be needed for the project, who is doing what in the project and all the legal issues will be considered here.
This stage will also see an SRS (Software Requirements Specification) document drawn up which will outline how the system will be used, and how it will function when used.
A TRD (Terms Of Reference Document) will also be drawn up which will outline things such as the stages of development, the time frame, the budget and who is responsible for what.
The spiral methodology is used because it allows for changes to be made along the way more easily, and allows for additional functionality to be implemented later. As each stage is completed it moves onto the next, but when it is near the end of the stages it restarts from the beginning, recovering all of the stages. This also ensures that any errors Will be noticed and corrected more often.
This methodology works well for larger projects, however it will be unsuitable for smaller projects.
The Rapid Application Development model allows for the quick production of a working prototype that the customer can use to gather feedback.
This methodology is used as it reduces the development time and allows for quick initial reviews to be made, however it will require highly skilled developers to work on it and only allows for modularized systems to be built.