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Systems Analysis, Design Methods and Development
Information system
- an arrangement of people, data, processes, and information technology that interact to collect,
process, store, and provide as output the information needed to support an organization.
Information technology
- a combination of computer technology (hardware and software) with telecommunications
technology (data, image, and voice networks)
Stakeholder
- any person who has an interest in an existing or proposed information system.
Stakeholders may include both technical and non-technical workers. They may also include both internal and external workers.
System analysis
- the study of a business problem domain to recommend improvements and specify the business
requirements and priorities for the solution.
System designer
- a technical specialist who translates system users' business requirements and constraints
into technical solutions. She or he designs the computer databases, inputs, outputs, screens, networks,
and software that will meet the system users' requirements.
System analyst
- a specialist, who study the problems and needs of an organization to determine how people,
data, processes, and information technology can best accomplish improvements for the business.
Where Do Systems Analysts Work?
Data
- raw facts about people, places, events, and things that are of importance in an organization.
Each fact is, by itself, relatively meaningless.
Information
- data that has been processed or reorganized into a more meaningful form for someone.
Information is formed from combinations of data that hopefully have meaning to the recipient
Knowledge
- data and information that are further refined based on the facts, truths, beliefs,
judgements, experiences, and expertise of the recipient. Ideally information leads to wisdom.
Object-oriented analysis and design
- a collection of tools and techniques for systems development
that will utilize object technologies to construct a system and its software.
Creeping commitment
- a strategy in which feasibility and risks are continuously re-evaluated
throughout a project. Project budgets and deadlines are adjusted accordingly.
Feasibility
- a measure of how beneficial the development of an information system would be to an organization.
SDLC
There are six phases in every Software development life cycle model:
1. Requirement gathering and analysis
2. Design
3. Implementation or coding
4. Testing
5. Deployment
6. Maintenance
1) Requirement gathering and analysis:
Business requirements are gathered in this phase. This phase is the main focus of the project managers and stake holders.
Meetings with managers, stake holders and users are held in order to determine the requirements like; Who is going to use
the system? How will they use the system? What data should be input into the system? What data should be output by the
system? These are general questions that get answered during a requirements gathering phase. After requirement gathering
these requirements are analyzed for their validity and the possibility of incorporating the requirements in the system to
be development is also studied.Finally, a Requirement Specification document is created which serves the purpose of guideline
for the next phase of the model.
2) Design:
In this phase the system and software design is prepared from the requirement specifications which were studied in the first
phase. System Design helps in specifying hardware and system requirements and also helps in defining overall system architecture.
The system design specifications serve as input for the next phase of the model.
3) Implementation / Coding:
On receiving system design documents, the work is divided in modules/units and actual coding is started. Since, in this phase
the code is produced so it is the main focus for the developer. This is the longest phase of the software development life cycle.
4) Testing:
After the code is developed it is tested against the requirements to make sure that the product is actually solving the needs
addressed and gathered during the requirements phase. During this phase unit testing, integration testing, system testing,
acceptance testing are done.
5) Deployment:
After successful testing the product is delivered / deployed to the customer for their use.
6) Maintenance:
Once when the customers starts using the developed system then the actual problems comes up and needs to be solved from time to
time. This process where the care is taken for the developed product is known as maintenance.
There are various Software development models or methodologies.
1) Waterfall Methodology
The Waterfall Model was first Process Model to be introduced. It is also referred to as a linear-sequential life cycle model.
It is very simple to understand and use. In a waterfall model, each phase must be completed fully before the next phase can begin.
This type of model is basically used for the project which is small and there are no uncertain requirements. At the end of each phase,
a review takes place to determine if the project is on the right path and whether or not to continue or discard the project. In this
model the testing starts only after the development is complete. In waterfall model phases do not overlap.
2) RAD (Rapid Application Development) Methodology
Rapid application development (RAD) - a system development strategy that emphasizes speed of development through extensive user
involvement in the rapid, iterative, and incremental construction of a series of functioning prototypes of a system that eventually
evolves into the final system (or a version). RAD is most popular for small- to medium-size projects.
The basic ideas of RAD are:
To more actively involve system users in the analysis, design, and construction activities.
To organize systems development into a series of focused, intense workshops jointly involving SYSTEM OWNERS, USERS, ANALYSTS, DESIGNERS, and BUILDERS.
To accelerate the requirements analysis and design phases through an iterative construction approach.
To reduce the amount of time that passes before the users begin to see a working system.
