The system development life cycle phases includes:
I. Systems analysis
2. System design
6. Parallel runs
8. Maintenance and modifications
The system development can be viewed either as system development life cycle phases Model or as Application Development Cycle. System Development Life Cycle, The SDLC Model, consists of three stages:
1. Definition stage: The definition stage consists of four sub-phases as follows: a. Proposal definition: It refers to the preparation of a request/proposal for a proposed application. The project may be for upgrading/ enhancing an existing application, or it may be for a new use. The plan attempts to justify the claim and should, therefore, be brief and crisp, rather than long winding and complex.
a. proposal should preferably contain specifics as regards organizational needs, likely benefits; corporate support required/expected time span, “schedule” considerations and, of course, “proprietary” clause. Once the proposal is approved, the process moves on to the next step, viz., the feasibility assessment.
b. Feasibility assessment: Feasibility is assessed by undertaking the feasibility study. The feasibility phase is a vital underpinning of the SDLC. It helps determine whether the proposed solution is feasible or achievable, given the organization’s resources, problems, and constraints. It also helps develop a set of selection criteria, a selection procedure, and effective decision-making. While assessing feasibility, the following major aspects of feasibility must be looked into:
i. Technical feasibility: Here, one asks questions like, “Can the organization implement the proposed solution with existing technology?, Can the solution be implemented with the available hardware, software and technical resources? Is the technology obsolete, intermediate, state-of-the-art? And Does it involve technology transfer?”
ii. Economic feasibility: Here, the likely savings to be affected and also the cost and benefits are assessed. It mainly assesses whether the benefits of the proposed solution would outweigh the costs. One can also look into the tangible and intangible benefits.
iii. Operational feasibility: It mainly examines whether the proposed solution is desirable within the available/ contemporary managerial/ organizational framework/ resources. Management, non-management and general considerations are also assessed.
iv. Schedule feasibility: Here, one examines as to whether the development process of the application/solution can be completed within the stipulated time. After examining/assessing the feasibilities as mentioned above,
c. Information requirement analysis: This is the most critical part of SDLC as the whole edifice of the information system would depend upon this phase. This phase carefully defines the information objectives of the system as also carefully identifies who needs what information, where, when and how.
d. Conceptual design: At this phase, both the systems analyst and the user are fairly well aware of what is expected of the system/ application. This phase, therefore, establishes a more clear and complete user-oriented design of the application.
2. Development stage: Once the basic activities related with the SDLC are completed in the definition stage, we move to the next stage, viz., the development stage, which consists of the following four sub-phases: a. Physical system design: This phase consists of those activities which involve preparation of the detailed technical design for/of the proposed system.
b. Physical database design: This is based on the existing database, and the approach followed for determining database requirements. However, database design would broadly include:
c. Program development: The specifications arrived at the physical database design phase define the programming tasks and provide direction for program development. Programming is a process of translating the specifications prepared during the design phase into program code. Program development, therefore, aims at coding and testing the programs required for the application/solution.
d. Procedure development: Procedure development refers to preparation/ development of manuals, instruction sheets, input formats/forms, etc. Procedure development can take place concurrently, along with program development, as the conceptual and physical design is available.
3. Installation and operation stage: This stage consists of the following three sub-phases:
a. Conversion: Conversion is the process of changing from the old system to the new system. While implementing conversion, a conversion plan, which provides a detailed schedule of all activities required to be carried out for installing a new system, has to be worked out. While moving over to conversion, different conversion strategies could be employed – the Parallel Strategy, the Direct Cut-Over Strategy, the Pilot Study Strategy and the Phased Approach Strategy.
i. Parallel strategy: This strategy is considered to be the most cautious, conservative and the safest. Under this strategy, both the current system as well as the proposed system, are run simultaneously till the correctness and accuracy are tested and assured. This strategy is sometimes also referred to as the “Parallel Run” Approach.
ii. Direct cutover strategy: In this strategy, the current system is replaced with the new system on a “cut off” or “pre-appointed day.” This strategy is considered to be risky as in case of any problem encountered during/after the switchover; no back up may be available.
iii. Pilot study strategy: In this strategy, the system is evolved by first introducing it in a section or department. Once the wording is found to be hassle-free, the system is then expanded and installed in the entire organization. The installation may be done simultaneously or in phases/stages.
iv. Phased approach: Under this strategy, the new system is made applicable either activity/function wise or level wise. To instance, a system might first be introduced at the top level, then at the middle management level and then further down the line on the typical `Back Office’ and ‘Front Office’ level.
b. Operations and maintenance: Once the system is put through conversion and appears to be operating without difficulty, the application is handed/turned over to operations. When the application becomes operational, users and technical specialists determine how well it meets the predefined goals/standards.
c. Post-audit: Post-audit is expected to take care of this post-installation review to ensure that the system is functioning effectively and efficiently from the “system” and user’s point of view. The audit team may consist of representatives from the users, system maintenance, operations, etc. Post-audit may look into areas such as information system quality, system control, technical evaluation, operational evaluation, economic evaluation, evaluation of existing hardware and software, evaluation by use of performance monitors, evaluation of systems logs, etc. Once system analysis, design, and implementation are complete, the system becomes fully functional, so that all are system development life cycle phases.