System Development Life Cycle (SDLC)

The systems development life cycle model has a well-defined iterative process. It
involves a few phases. The development follows the phases fairly exactly. The process
theoretically never ends as the cycle gets repeated, that is, on completion of one cycle the next
cycle starts with preliminary investigation.
In this approach the systems design activities such as preliminary investigation,
requirement analysis, systems design, systems acquisition and systems implementation are
carried out in strict sequence.
The traditional system development life cycle stages are to be gone through serially and
in strict sequence. Systems development life cycle is made up of the following stages:
a. Preliminary Investigation
It is an investigation into the problem and comes up with options for the management to
consider for the proposed system change. The preliminary investigation examines the request for
system change in detail to know precisely the requirements. A set of feasibility studies is used to
ascertain the viability of the project. This includes technical feasibility, economic feasibility, and
operational feasibility and schedule feasibility. The report is submitted to the management for
consideration and action.

The steps include:

• Conducting preliminary analysis
• Determination of objectives, scope and constraints of the proposed system.
• Developing alternative solutions
• Estimate cost and benefits of each such alternative 
• Submit a preliminary report with recommendations.

b. Requirement Analysis
If the management permits the system development to continue after studying the
preliminary investigation report, new system requirements are analyzed in detail. After the
analysis, the results are presented in requirement report to the management. Requirement is any
feature that is to be included in the new system.
This process starts with the defining scope of system analysis and identifying users of the
current system. Analysts carry out a study of current user requirements and deficiencies of the
current system in meeting them. It describes the new system and the benefits it provides to the
users. It also produces a requirement definition document.
Steps include;

• Gather data employing tools like document walk through, interviews, questionnaires, observation etc.
• Analyze the data using CASE tools, data flow diagrams, system flowcharts, decision tables etc.
•  Prepare a system study completion report.

c. Systems Design
The requirement analysis provides the input for designing a new system to meet the user
requirements. The new system is planned in detail at this stage. Design translates the
requirements into ways of meeting them. It produces specifications of a physical system that is
expected to meet the requirements. Specifically this includes output design, input design,
procedure design, database design and control design.
This includes:

• Output design
• Input design
• Database design
• Procedure design
• Control design
• Documentation of design.

d. Systems Acquisition
Hardware, software and service needs of the new system are ascertained and vendors
chosen for the acquisition.
This includes:

• Develop or acquire software
• Acquire hardware
• Test the system

e. Systems Implementation
The system is finally tested and put into operation. Implementation comprises all the
activities involved in putting the system together physically and getting the people adopt the new
system. This requires training for people and conversion of data and procedures to be in
agreement with the new system.
Steps include:

• Train the operators and users.
• Convert to the new system
• Develop final documentation

f. Systems Maintenance
The system may need modifications or updating due to changes in requirements. If the
changes are minor, They are incorporated into the system. If the changes are major, they start
another cycle of system development.
Steps include:

• Perform system audit to see whether the new system implemented is as it should be
• Perform evaluation of system performance against a set of criteria.