System Analysis and Design: Feasibility Study and SDLC Models

System Analysis and Design

Table of Contents
1. Task 1................................................................................................................................................2
1.1 System lifecycle model evaluation.....................................................................................2
1.2 Importance of procedural/staged lifecycle in a system investigation:......................7
2. Task 2................................................................................................................................................8
2.1 Feasibility report component:..............................................................................................8
2.2 Different feasibility criteria impact on a systems investigation..................................9
3. Task 3..............................................................................................................................................11
3.1 Investigating the system, for meeting the business....................................................11
3.1.1 Introduction....................................................................................................................11
3.1.2 Definitions and Abbreviations...................................................................................12
3.1.3 Overview.........................................................................................................................12
3.1.4 Overall Description.......................................................................................................12
3.1.5 Product capabilities......................................................................................................13
3.2 Investigating the system by using various tools and techniques............................14
3.2.1 ERD...................................................................................................................................14
3.2.2 Context Level DFD........................................................................................................14
3.2.3 Data flow Diagram.........................................................................................................15
3.3 Investigating the Specific Requirements........................................................................19
3.3.1 External Interfaces........................................................................................................19
3.3.2 Software Interfaces Requirement..............................................................................20
3.3.3 Hardware Interfaces Requirement............................................................................20
3.3.4 User Interfaces Requirement.....................................................................................20
3.3.5 Functional Requirements............................................................................................20
3.3.6 Non-functional Requirements....................................................................................21
3.4 Verification and Validation.................................................................................................21
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1. Task 1
1.1 System lifecycle model evaluation
To build, plan and control the entire software development process, the SDLC method is
used. It is also used to design and develop the customized software product. To make the
software product as standardized, this method is popularly used. Mainly 6 software
development life cycle models are available. It is the difficult task to choose the best one from
these 6 different life cycle models. To select the best one, it is necessary to compare all the
models and also to analyze the merits and demerits presented in these models.(Treiber and
Kesting, 2013)
Waterfall Model
Among 6 different SDLC models, Waterfall model is very easy to process. Simple classic
life cycle phases are followed by the waterfall model. The name of this model is the ‘Linear-
sequential life cycle model’. In waterfall model, totally 6 phases are available. Before entering
into the next phase, the actions available in the present phase must be completed fully. At the
end of each phase of the model, there is a review team. They are responsible for verification
and validation process. These processes are used to find the track of the project is correct or
not. The below figure shows the waterfall model with its phases.
Merits:
1. It is very simple and easy to understand everyone.
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2. Each phases presented in the waterfall model is independent to each other. So the
result of each product is developed separately.
3. Small project with clear requirement, the waterfall model is used for that project.
Demerits:
1. If the phases are integrated with each other, the error or no output will be obtained
because each phase is independent to each other. So risk involved in this model is high.
2. For big project, it is not suitable.
Iterative model
Iterative model is otherwise known as the ‘Multi waterfall model life cycle’. Small cycles are
used in this model and also these cycles are worked iteratively. At the end of each iteration
process, a working on a series of phases will be carried out. So on each end of cycle, working
output software can be obtained as a result. The below figure shows the phases available in the
iterative model.(Traffic flow theory and characteristics, 2013, 2013)
Merits:
1. If the life cycle is being processed, the output or working software will be obtained at
earlier.
2. Due to occurrence of small iterations, the developed product testing and the debugging
is very easy.
Demerits:
1. This model is rigid and difficult to understand.
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2. At the end of each iteration cycle, there is architectural problem. The main reason for this
problem is that the requirements are not collected properly at the starting stage of the
development process.
Spiral Model
Spiral model is the simplest model without risk analysis. The spiral model plays the vital
role in SDLC. The following steps are used for spiral model.
This model allows the various type of users to use the software product and the system
requirements are well explained and it is used to identify the system aspects.
Preliminary design is the one of the most important step in the spiral model. This spiral
model is used to make a cost effective strategies to work on a project. The new system is
developed in this phase. The characteristics of the final output are represented as the scaled
down system.
 We can easily evaluate the strength, weakness and risk involved in the system.
 For new prototype, Functional and non-functional requirements are well defined.
 plan and design of newly developing prototype can be started
 Testing process will be carried out for developing the project.
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Merits:
1. For big and critical projects, the spiral model is used very efficiently.
2. At earlier of lifecycle, the working or output software is developed
3. The high level risks are analyzed.
Demerits:
1. When compared to other models, the cost of model installation is very high.
2. It is not applicable for small projects.
3. The success of project depends on the risk taken on analysis phase only. To analyze the high
level of risk, an expertise is required.
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