System Development Life Cycle Tutorialspoint

Introduction:

A system can be defined as a combination of some related components of files that interact with one another to perform some specific tasks. Our main discussion here is focused on the computer Application Software development process, leaving aside the different software packages which are always available in all markets. To develop a system, several distance faces are to be a workout. For this purpose, SDLC was developed, which is an organized way to develop a successful system. It involves 5 phases as shown

System Development Components:

The system component comprises of the following necessary components

1. Hardware
2. Software
3. People/Users
4. Data/Information
5. Communication setup

Five Phases:

It involves seven phases as shown below

1. Preliminary investigation
2. analysis
3. design
4. coding
5. testing
6. implementation
7. maintenance

System Development Life Cycle:

• Preliminary Investigation:

The objective of the preliminary investigation is to conduct an initial analysis and finding of the system as discussed below:

System Identification:

The system is to be identified at this type of stage. This is a very important step as everything done in the future will depend based on this definition.

System scope:

The scope of the computer network system development is established at this stage. Sometimes, it becomes necessary to curtail the required projects to certain limits due to financial, political, or time constraints problems.

Alternate solutions:

There may be an alternate solution to develop the system. The best strategy in this regard would is to interview the concerned people inside the organization, clients, or customers of the system, suppliers, and consultants. We can also watch what the competitors are doing for the same type of computer systems development.

Feasibility Study:

We have to see the financial, political, and time-frame liabilities to go-ahead for the system. There may be some social and technical constraints to be considered also in system development life cycle.

Preliminary plan:

Here, we need to wind up all the findings and submit them as a written any type of document for approval. The readers of this document also known as the feasibility reports are top managers who will then decide about the future actions to be taken, based on this report. They might like to make few amendments to the project or shelve it, depending on the whole preliminary investigations.

• System analysis:

Here, the analyst will conduct the following activities which are used:

Needs Analysis: 

This activity is also known as Requirements Analysis. Here, the analyst would sum up the requirements of the computer system from the users and talented managers. The developed system should satisfy these requirements during the testing phase.

Data Gathering:

For this activity, the system analyst uses different tools and methods,  depending on this situation. They are discussed as under:

Written documents:

In case we want to computerize the existing manual system or upgrade the existing computer-based system, much of the handful of information can be made available using these documents. They are the reports, forms, memos,   business plan statements, organizational charts, and many others.

Interviews:

Interviewing the managers, users/clients, suppliers, and competitors will help the analysts/designers to gain more knowledge about the computer analysis system. The emphasis is on the fact that the questions to be asked from the users should be precise and relevant.

Questionnaires:

It may be difficult to interview many people in this department, so it is better to design some questionnaires to collect the information from as many people as we like to ask them. This is a very convenient and inexpensive method to collect a handful of data but sometimes the response may be ambiguous and insufficient.

Observations:

The computer system analyst or his team may go and watch the working behavior, and similar things to know more about the similar computer analysis system around. He may be a participant or non-participant in the required data to observe depending on the permission he got from the other party.

Sampling:

If there were a large number of people or events involved in the computer system, it would be better to work on a portion of all of them to save time to work.

• Data Analysis:

As we are living in the"Information age" so it is generally believed in today's computing system scenario that data or information of any type is the most precious commodity. Therefore, data must be accurate, complete, and readily available in the computer analysis systems we design. So to keep it in proper shape process, we have many tools available in this.

Analysis Report:

Once the analysis work is over, we need to document it in a presentable form to the higher management for their interview and approval of the project. 

• Design:

In this phase of SDLC, the analyst works on the preliminary design, detail design, and then writes a detailed report.

Logical design:

It describes the general functional capabilities of a proposed computer system. It reviews the computer analysis system requirements and considers the major computer system components.

Physical Design:

It describes how a proposed computer analysis system will deliver the general capabilities described in the logical design. It  will address the following points of these designs: 

Output data requirements, storage data requirements, processing data requirements, and system data control, and backup/recovery of data, to implement any type of document.

Report:

A detailed report on logical, physical design is to be submitted to the higher management along with some sort of presentation, explaining to them the details of the proposed system.

• Coding:

This is the core area of the computer coding system development process. It consists of writing the segments and programs, which will be coupled together in the shape of a complete system. It needs a lot of time, effort, and budget to acquire a workable perfect system.

• Testing:

Having proper hardware acquired. the programs can be tested in two stages:

Unit-testing:

It is also called modular testing where individual modules, programs can be tested using test data.

System-testing:

In this, parts or modules are linked together to test their workability as one system. Actual data may be used to do the computer system testing and at the same time, erroneous type of data can also be used to check whether the computer system fails or not.

• Implementation:

This activity consists of transferring computer hardware, computer software, and any type of data to the new working environment. Users of the computer data analysis system are also trained in this phase.

An implementation may be achieved in 5 approaches.

1. Direct Implementation
2. Parallel Implementation
3. Phased Implementation
4. Pilot Implementation
5. Users Training

• Maintenance:

The last phase of SDLC adjusts and improves the computer system development by considering the users' evaluation, feedback, and enhancements based on their due recommendations. In this phase, due maintenance and help are also provided to the users against their queries, problems, and ambiguities.