Explain the System Development Life Cycle?

The System Development Life Cycle involves mainly the three steps or the stages and these can be summarized as the follows

1. The Definition Stage – This stage further consists of the following four sub-stages :

a. Proposal Definition

I. Involves mainly the preparation of a request for a proposed application.
II. Proposal mainly helps in the up gradation of an existing application.
III. The application must not be long winding and complex.
IV. The application can be fully justified.
V. The application must be brief and also should be very crisp.
VI. The proposal must consist of the regards, the organizational needs, the organizational support, the required time span and also the proprietary clause.

b. Feasibility Assessment

I. Helps in finding out the extent of the feasibility.
II. Acts as a very important step of the System Development Life Cycle.
III. Helps in the determination of whether the proposed solution is feasible in the nature or achievable, depending on the resources, the problems and the constraints of the organization.
IV. In this step, one is able to make a group of the selection criteria, a selection procedure and also an effective decision making.
V. For having an in-depth analysis of the feasibility, one must keep into notice the following points

A. Technical Feasibility
The various questions that can be asked in this step involves :
a. Can the organization implement the proposed solution with the help of the technology that is present or that is available?
b. Can the solution be implemented with the help of the hardware, the software and the technical resources that are available to the organization?
c. Is the technology that is available to the organization obsolete in the nature or not?
d. Is the technology that is available to the organization intermediate, state of the art or very HiFi in the nature?

B. Economic Feasibility
a. The assessment of the savings to be effected and the cost benefits takes place.
b. Helps in the assessment of the possibility of whether the benefits of the proposed solution would outweigh the costs or not.
c. Helps in the calculation of the tangible and also the intangible benefits.

C. Operational Feasibility
a. Helps in the assessment of the management, the non management and the general positions of the organization.
b. Whether the proposed solution is desirable within the available managerial framework, can also be examined by performing this step in the feasibility assessment phase.

D. Motivational Feasibility
a. The assessment of the degree of the motivation that is used for providing the much needed support to the development and the implementation of the application from the users is done in this step.

E. Schedule Feasibility
a. The degree of the chances of whether the development process of the application can be completed within the stipulated time or not, are assessed.

After performing the Feasibility assessment, one need to prepare the report of the Feasibility and it should be kept in mind that the Feasibility Report must consist of the following points

1. The basic information of the proposal.
2. Highlights as the regards expected costs and the benefits.
3. A gist of the technical, the operational, the motivational and the schedule Feasibility assessment.
4. The expectations linked to the development schedule and the resources that are required.

C. Information Requirement Analysis

a. Very important part of the systems development life cycle.
b. Acts as the base for the whole edifice of the information system.
c. The information objectives of the system can be determined in a very efficient manner.
d. Helps in the determination of the needs of the information when, where, how and who requires that information.
e. Gives vital information about the following

I. Inputs and the outputs data for the reports.
II. Routine and the ad hoc queries.
III. Functional requirements.
IV. Conceptual schema.
V. User interface requirements.

D. Conceptual design

a. Usually called as the logical design.
b. Helps in the establishment of the very clear and the very useroriented design of the application.
c. Helps in the determination of would be – like picture of the system solution.
d. Includes the documenting flow of the various types of the activities and the processing.
e. Gives a detail about the contents of the inputs and also of the outputs.
f. Explains the different functions that are mainly expected to be performed.
g. Includes the general descriptions as regards different manuals.
h. Explains the following up / auditing / controlling of the procedures.

2. Development Stage
The Development Stage forms a very important and a critical and also a resultoriented stage involving further of the following stages

a. Physical System Design – In this step, those activities are performed which help a great deal in the formation of the technical design in detail for the proposed system. With the help of the physical system design, the following can be efficiently specified and also designed

I. The flow of the work.
II. The flow of the user functions.
III. The data communication requirements.
IV. The overall structure of the programs.
V. The security-this point is very much important and also necessary to be taken care of.
VI. The backup points to be taken care of or to be considered.
VII. The quality assurance plan.

b. Physical Database Design – The exiting database and the approach that is followed for the determination of the database requirements acts as a strong base for the physical database design. With the help of the physical database design, the specification of the following can be done in a very efficient manner

I. Logical data relations.
II. Volume.
III. Special requirements.
IV. File organization.
V. The design.
VI. Record specification.

c. The Program Development – The various types of the programming tasks can be explained with the help of the specifications that have arrived at the physical database design phase. And as a result of this, one gets a great help in the development of the program. Now here, it becomes very much necessary to completely have the knowledge about the programming. So the programming can be defined as the process which involves the translation of the specifications formed during the design phase into the program code.
The development of the program is very much necessary as it aims at the coding and then testing the various programs that are needed for the application.

The program development involves a great use of the different types of the techniques mainly for the development of the programs and these techniques generally include the following

I. Modularity
II. Structured programming
III. Applications generators
IV. Application packages

d. Procedure Development
I. Involves the preparation of the manuals, the instruction sheets, the input formats.
II. Can be performed concurrently along with the program development.
III. In the procedure development, the conceptual design and also the physical design are available.
IV. In this step, it is very necessary to take care of the documentation.
V. The need for the development of the procedure is very must for all those, who will be interacting with the application.
VI. The procedures have to be or can be developed for the primary users and also the secondary users of the computer operating personnel.
VII. Training procedures can also be developed and also must be developed for helping in the implementation and then the following up.

3. The Installation and the Operation Stage
This stage acts as the final stage of the system development life cycle and consists of some sub-stages, which can be summarized as the follows

a. The Conversion

I. Involves the activity of the changing from the old system to the new system.
II. The working out of the conversion plan is a must in this stage.
III. For actually conducting a conversion; performing the acceptance testing, file building and the user training is very necessary.
IV. In this sub-stage, use of the different types of the conversion strategies can be done, so having a knowledge about these strategies is very much important and these strategies can be summarized as the follows

A. The Parallel StrategyThis strategy is also called as the parallel run approach. A very crucial point to remember about this type of the strategy is that it is very cautious, very much conservative and most importantly very safe in the nature. This strategy has the ability to work, when the current system and the proposed system run simultaneously till the correctness and the accuracy are tested and also assured.

B. The Direct Cut Over Strategy – In this stage, the replacement of the current system is done with the new system on a cutoff or preappointed day. But this type of the strategy is somewhat risky as compared to the parallel strategy. This type of the strategy is risky in the nature because of the fact that whenever there occurs any type of the problem during the process of the switching over, there is no backup present and hence as a result of this, the degree of the risk involved goes up drastically.

C. The Pilot Strategy- The evolution of the system takes place after its introduction in the section or the department. When the working becomes free from any type of the hassles, then the expansion of the system takes place. After this the installation of the system is done in the whole organization. One critical point that must be kept in mind here is that the installation that is done can be done simultaneously and also in the different steps or the phases.

D. The Phased Approach – In this type of the strategy, the new system can be made applicable functionwise or levelwise. In this type of the approach, firstly the system is brought at the top level, after this at the middle management level and then at last at down the line on the typical ‘back office’ and the ‘front office’ approach.

b. The operations and the maintenance
After the system passes through the conversion step, the next step which follows is of the operations and then of the maintenance. But one very important point to be remembered here is that this process can be performed only when the system is operating without any types of the snags. In this step, once the system is made operational, the estimation about the degree of the chances to meet the predefined goals can be made and this is done by the users and the technical specialists.

During the operation of the application, it is also possible to take a look at the decisions involving the questions like whether any of the revisions or the modifications is warranted or not?

Now comes the turn of the department that is responsible for looking after the maintenance work and this department is generally referred to as the maintenance department. But before going any further, it is very necessary to have a good and a basic understanding of the meaning of the word ‘maintenance’.

Maintenance can be defined as the changes in the hard – ware, the software, the documentation, the procedures to an application system in order to correct the different types of the errors that are present and also to meet the various new requirements and ultimately to improve the efficiency of the processing. Hence, the main duty of this department is mainly to look over the various types of the changes that may occur during the process.

c. Post Audit
The next step after the system is made operational is the step of the post audit and this step of the post audit is very much important to perform as the provision for the post installation review must be available.

The major areas of the concern like the information system quality, the system control, the technical evaluation, the operational evaluation, the economic evaluation, the evaluation of the existing hardware and also the software, the evaluation of the use of the performance monitors and the evaluation of the system logs, can be taken care of in a very good way with the help of the post audit.

With the help of the postaudit, one can in a very proper way, also take care of the post installation review and as a result of this helps in keeping the functioning of the system in a very efficient state.

For taking care of all these things, the audit team is very much responsible and generally consists of the representatives from the users, the system maintenance and the operations etc.