System Development Life Cycle -1

System development life cycle is also known as the system life cycle, problem-solving cycle, system development cycle, system development process and system study.Perheps,the simplest view of this life cycle is a sequence of tasks, an apporach that was used in the early days of developing computer based system.

A system development life cycle is  the evolutionary process that is followed in implementing a computer-based system or subsystem. A system development life cycle is a framework consisting of a series of various different tasks to achieve the specific centralized objective in the development of a system. SDLC is an application of the systems apporach to the task of developing and using computer-based system. As such the SDLC is a methodology but its pattern is being influenced by their need to develop the system more quickly.

Various phase of SDLC : -

The system development life cycle consist of seven major phases :

(a) Preliminary Assessment

(b) Feasibility study

(c) Analysis

(d) Design

(e) Implementation and testing

(f) Maintenance

(g) Review and evolution

Preliminary Assessment : - 

The first phase of any project is the preliminary assessment. The base of this phase is recognition of needs for improving an information system or a procedure. This need leads to a preliminary survey or initial  investigation  to determine  whether an alternative system  can solve the problem. This brief  investigation of the system underconsideration will be provided to the organizations streeing team and any project team, a set of items of reference for more detailed work.

There are various external and internal  sources  to be described , as given below :

1. Goverment polices,rules and regulation sometime lead to change some important procedures, some format etc.

2. Consumer  can given their feedbacks about  the existing systems  and want to change such by a new system.

3. unions like the union of truck divers want some type modification.

4. The market competitionarises suddenly and now it is essentially required to modigy or replace the exesting system to include new hardwares, software, technology etc.

Internal Sources

1. Organization itself wants to add some advanced techonology to modify the existing applications or to make    an improvement in it, like an organization acquires another organization.

2. Top management can also reuire the changes, like related to the cost.

3. User factors also sometimes require the change, like for any risk and potential returns.

4. Even the investigator himself (system analyst) may require it.

Feasibility Study: -

As a initial investigation is completed, it leads to a more detailed investigation of the system the conclusons of the initial study become the inputs for the detailed study feasibility study is called like because as in the first phase, we just check briefly about the problems related to the old system. Feasibility study can be defined as:-

Feasibility Study is test of a system proposal according to its workablity, impect on the organization, ablity to meet user needs , and effective use of resources. The task of this phase should clearly define:

1. The users demonstrable needs .

2. Availability of resources. 

3. Estimate the resources required.

4. Impact of the system.

5. Define and document in outline proposed system.