Answered! 1. What are the three major components/tasks of the systems design phase of the SDLC?…

System Development Life Cycle (SDLC) is a series of 3 main phases to create a hardware system only, a software system only or a combination of both to meet or exceed customer’s expectations.

System is a broad and a general term, “A system is a set of interacting or interdependent components forming an integrated whole” it’s a term that can be used in different industries, therefore Software Development Life Cycle is a limited term that explains the phases of creating a software component that integrates with other software components to create the whole system.

System Planning and Analysis-

The Planning phase is the most crucial step in creating a successful system, during this phase you decide exactly what you want to do and the problems you’re trying to solve, by:

• Defining the problems, the objectives and the resources such as personnel and costs.

• Studying the ability of proposing alternative solutions after meeting with clients, suppliers, consultants and employees.

• Studying how to make your product better than your competitors’.

After analyzing this data you will have three choices: develop a new system, improve the current system or leave the system as it is.The end-user’s requirements should be determined and documented, what their expectations are for the system, and how it will perform. A feasibility study will be made for the project as well, involving determining whether it’s organizationally, economically, socially, technologically feasible. it’s very important to maintain strong communication level with the clients to make sure you have a clear vision of the finished product and its function.

System Design and Implementation-

The design phase comes after a good understanding of customer’s requirements, this phase defines the elements of a system, the components, the security level, modules, architecture and the different interfaces and type of data that goes through the system.

A general system design can be done with a pen and a piece of paper to determine how the system will look like and how it will function, and then a detailed and expanded system design is produced, and it will meet all functional and technical requirements, logically and physically.This phase comes after a complete understanding of system requirements and specifications, it’s the actual construction process after having a complete and illustrated design for the requested system.the system is ready to be deployed and installed in customer’s premises, ready to become running, live and productive, training may be required for end users to make sure they know how to use the system and to get familiar with it, the implementation phase may take a long time and that depends on the complexity of the system and the solution it presents.

System Testing and Maintainance-

Bringing different components and subsystems together to create the whole integrated system, and then Introducing the system to different inputs to obtain and analyze its outputs and behavior and the way it functions. Testing is becoming more and more important to ensure customer’s satisfaction, and it requires no knowledge in coding, hardware configuration or design.Testing can be performed by real users, or by a team of specialized personnel, it can also be systematic and automated to ensure that the actual outcomes are compared and equal to the predicted and desired outcomes.Periodic maintenance for the system will be carried out to make sure that the system won’t become obsolete, this will include replacing the old hardware and continuously evaluating system’s performance, it also includes providing latest updates for certain components to make sure it meets the right standards and the latest technologies to face current security threats.

Part 2)- The four options for system conversion are:-

1. Run the New System Parallel to the Old
2. Phase in the New System
3. Use One Site as a Pilot Site
4. Direct Changeover

Part 3)- The four type of system maintenance process are:-

1. Corrective maintenance –

It deals with the repair of faults or defects found in day-today system functions. A defect can result due to errors in software design, logic and coding. Design errors occur when changes made to the software are incorrect, incomplete, wrongly communicated, or the change request is misunderstood. Logical errors result from invalid tests and conclusions, incorrect implementation of design specifications, faulty logic flow, or incomplete test of data. All these errors, referred to as residual errors, prevent the software from conforming to its agreed specifications. Note that the need for corrective maintenance is usually initiated by bug reports drawn by the users.

In the event of a system failure due to an error, actions are taken to restore the operation of the software system. The approach in corrective maintenance is to locate the original specifications in order to determine what the system was originally designed to do. However, due to pressure from management, the maintenance team sometimes resorts to emergency fixes known as patching. Corrective maintenance accounts for 20% of all the maintenance activities.

2. Adaptive Maintenance-

Adaptive maintenance is the implementation of changes in a part of the system, which has been affected by a change that occurred in some other part of the system. Adaptive maintenance consists of adapting software to changes in the environment such as the hardware or the operating system. The term environment in this context refers to the conditions and the influences which act (from outside) on the system. For example, business rules, work patterns, and government policies have a significant impact on the software system.

For instance, a government policy to use a single ‘European currency’ will have a significant effect on the software system. An acceptance of this change will require banks in various member countries to make significant changes in their software systems to accommodate this currency. Adaptive maintenance accounts for 25% of all the maintenance activities.

3. Perfective Maintenance –

Perfective maintenance mainly deals with implementing new or changed user requirements. Perfective maintenance involves making functional enhancements to the system in addition to the activities to increase the system’s performance even when the changes have not been suggested by faults. This includes enhancing both the function and efficiency of the code and changing the functionalities of the system as per the users’ changing needs.

Examples of perfective maintenance include modifying the payroll program to incorporate a new union settlement and adding a new report in the sales analysis system. Perfective maintenance accounts for 50%, that is, the largest of all the maintenance activities.

4. Preventive Maintenance-

Preventive maintenance involves performing activities to prevent the occurrence of errors. It tends to reduce the software complexity thereby improving program understandability and increasing software maintainability. It comprises documentation updating, code optimization, and code restructuring. Documentation updating involves modifying the documents affected by the changes in order to correspond to the present state of the system. Code optimization involves modifying the programs for faster execution or efficient use of storage space. Code restructuring involves transforming the program structure for reducing the complexity in source code and making it easier to understand.

Preventive maintenance is limited to the maintenance organization only and no external requests are acquired for this type of maintenance. Preventive maintenance accounts for only 5% of all the maintenance activities.