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Information Systems Development
Terms in this set (56)
Systems Development Life Cycle Phase 1
Systems Development Life Cycle Phase 2
Systems Development Life Cycle Phase 3
Systems Development Life Cycle Phase 4
Systems Development Life Cycle Phase 5
What must organizations consider when developing information systems?
When developing an information system, what requirements must be clearly defined.
The Cooperate Requirement
The information technology (IT) professionals must be willing to work with the users to go through every test scenario to ensure that all requirements are addressed.
The Expectations Requirement
To do this, the users must first identify everything the system is expected to do. They can then work with the IT staff to explain their expectations.
The Previous Work Requirement
One way to help identify all requirements is to examine the inputs and outputs used previously, and make sure they have been addressed in the new system.
The Ask Questions Requirement
When they communicate, both users and IT staff must ask detailed questions and provide detailed answers regarding all possible requirements. When organizations put the required time and effort into determining requirements, they improve their chances for success in systems development.
What happens when a requirement needs to be added?
The process of adding a requirement depends on how far along the team is in the development process. The larger the project and the farther along it is in development, the more difficult it is to add functionality.
Changing Requirements Reworking Process
Changing Requirements Continuing Current Process
The second option is to continue the development process and add requirements as new features in future versions of the system
Changing Requirements Planning Ahead
Adjusting requirements is not a simple task. The difficulty of the adjustment process emphasizes the importance of determining all system requirements before beginning development.
Organizations commit large resources to systems development and expect a return on their investment. It is difficult to put a dollar figure on the cost of a systems development project. Some tools that can be used to determine the system's cost include the following:
Cost projections on systems development
Examining past projects and their costs
Ensure the system includes the requirements.
Test the system.
Assist in training their peers.
Sometimes companies are not able to fully manage the needs of their clients and customers due to a small staff or rapid growth. Businesses can use two possible methods that provide solutions: outsourcing, or in-house consultants.
Companies choose to outsource work for various reasons, but the primary reason is financial advantage. However, outsourcing can be problematic for companies as it eliminates communication between the company and clients or patrons.
In-House or Consultants
Unlike outsourcing, in-house operations are also viable business solutions for a company. In the case of in-house operations, a company uses its own employees to perform payroll, email, and call center services. Some companies use in-house staff to keep transactions internal. For example, financing businesses use internal staff and resources to extend the customer's credit.
If a company uses information systems, it will often use in-house software to manage its work based on the needs of its business. However, if a company cannot afford, or does not have the resources to develop, its own software to support an information system plan, the company may hire consultants to develop the software to meet its needs.
Systems Development Life Cycle Approach
Phase I: Planning
Phase II: Analysis
Phase III: Design
Phase IV: Implementation
Phase V: Maintenance
Systems Development Life Cycle Approach
Is a rigid, phased approach to systems development that, if followed correctly, offers a high chance of success. Systems that are developed by using the SDLC are usually high quality, meet an organization's requirements, are completed on time and within budget, work efficiently, and are cost-effective.
Organizations that use the SDLC might have a varying number of phases, depending on the importance of each phase to the organization. Regardless of how many phases are used, they encompass the same tasks; the difference lies in the structure of each phase. For the purposes of this topic, the SDLC is divided into the following five phases:
Determining User Requirements in the Systems Development Life Cycle Approach
The need to communicate in detail with the users of the proposed system. You need to figure out their needs and then translate them into system requirements.
Requirements Creep in the Systems Development Life Cycle Approach
After the requirements are determined and the system is under construction, you must try to control the number of new requests users make. During later phases of development, it is especially difficult to add functionality without returning to earlier phases and thus delaying development. This is why it is important to determine all the requirements before beginning a project.
Time and Budget Considerations Systems Development Life Cycle Approach
The pressure is always on to meet schedules and budget estimates. It is crucial to determine all costs and scheduling requirements at the beginning of the project and then strive to meet those goals.
Technological Advances in the Systems Development Life Cycle Approach
Organizations need to consider the latest technologies at the beginning of a project, rather than after several project phases have been completed. Improved technologies are desirable, but need to be evaluated fully during the initial development phases.
Managing the Systems Development Life Cycle Work Breakdown Structure
The work breakdown structure is an outline view of the tasks to be completed, which are organized by phases. This document provides a scope and schedule of the major systems development tasks in systemic order.
Managing the Systems Development Life Cycle Gantt Chart
Organizations use project management software to manage the project from a higher-level perspective. Each task is broken down into those tasks that must be done before the next task starts, those that can be done concurrently, and those that are dependent on the current task before they can start.
Systems Development Life Cycle Strengths
Ability to monitor and maintain control over large projects
Detailed phases that guide systems development in a controlled manner
Great user input into requirements
Easy systems maintenance
Ability to make changes to the information technology staff without affecting the development process
Systems Development Life Cycle Weaknesses
Longer development time than other methodologies
Increased development costs
Need for well-defined systems at outset, before development starts
Some difficulty in estimating scheduling and budgeting
Limited user input
Phase 1: Planning
The planning phase determines the scope of the system being developed, and identifies the tasks the system must accomplish. The planning phase begins when a need for a new or revised system is identified, and has three major tasks:
Phase 1: Planning Define the Scope of the System
What the system will do and how broad the scope of the system will be need to be determined first. The goal of the system is also taken into account to ensure the system meets the organization's needs
Phase 1: Planning Conduct Feasibility Studies
Four feasibility studies are undertaken to determine the viability of the project. They can be remembered by using the acronym COST, as follows:
Cost: Does the organization have the resources to build the proposed system? It is not unusual to use cost-benefit analyses to ensure funding is available for the entire project. Estimates should be liberal when budgeting for unknowns.
Organizational: To be viable, the project should fit within the organization's culture, customs, and goals.
Scheduling: A preliminary schedule is drafted, with built-in padding, to determine the project start and completion dates. When the schedule is determined, you must assess whether it fits the organization's plans.
Technical: Is the technology to build the system available? Does your staff have the expertise to build it? If not, what are your options? It is important to resolve these issues to determine whether you develop the system in-house or contract the work out to a consulting firm.
Phase 1: Planning Form a Project Team
The project team is composed of an information technology (IT) project manager, IT staff, a representative of upper management, and users of the proposed system.
Phase 2: Analysis
The analysis phase identifies the features and functionality of the system, using the project plan from Phase 1 as the input. When each of these phases is completed, the desired output—which is the component design—is achieved. Major tasks of this phase include the following:
Identify System Requirements
Identify System Object Requirements
Identify System Security
Identify Personnel Procedures
Phase 2: Analysis Identify System Requirements
This task puts pressure on the users of the system to identify every task—daily, weekly, monthly, and yearly—the new system needs to support. Strong interviewing skills are required to gather this detailed information from users.
Phase 2: Analysis Identify System Object Requirements
This task identifies the type of forms, reports, and queries needed to produce the information required.
Phase 2: Analysis Identify System Security
This task identifies the preliminary security requirements of the system.
Phase 2: Analysis Identify Personnel Procedures
This task identifies the personnel needed to run the system, and the procedures that must be followed.
Phase 2: Analysis Create a Data Model
This task identifies tables and fields for a new or revised database.
Phase 3: Design
Using the input of the component design from Phase 2, the design phase creates each of the features and functionalities of the system to include in the components of the system. The output of Phase 3 is the system design, which is achieved through several tasks:
Phase 3: Design-Design Hardware
Hardware must be identified and then ordered.
Phase 3: Design-Design Programs
Depending on the source of the programs, certain designs need to be completed.
Phase 3: Design-Design a Database
Tables and fields must be normalized and designed.
Phase 3: Design-Create Job Descriptions
Job descriptions must be created for the proposed users of the system, along with the procedures they will use.
Phase 3: Design-Create System Procedures
System procedures pertaining to security, data backup, and system failure recovery need to be created.
Phase 4: Implementation
The implementation phase brings the system to life. This includes building the system, testing the system, converting the system, and then training the users, with the input of the system design from Phase 3. Major tasks of this phase include the following:
Phase 4: Implementation-Completing the System
The system is built and ready for use.
Phase 4: Implementation-Testing
Test scripts and test plans are developed to use when testing the system. This task includes the following types of tests:
Unit tests: These are stand-alone tests that use controlled input. The output is then compared with the test script and test plans. If the script matches the plans, it passes. If they do not match, either the test scripts are incorrect or the program is incorrect and needs to be fixed.
Integration tests: These are tests during which input is fed into the system from other programs, and output from the system is fed into other programs to ensure that program interfaces are accurate. Again, if errors surface, the system needs to be fixed.
User tests: These are the final tests. Users of the system actually use the new system to look for errors. User acceptance is required for the system to be approved.
Phase 4: Implementation-Conversion
If a system is replacing another system or systems, programs need to be written to convert the data from the old system to the new system. There are four main ways an organization can convert its data:
Parallel: The entire organization runs both the old system and the new system. After the new system is deemed sufficient, the old system is cut off and only the new system runs. The advantage to this method is that nothing is lost if the new system does not work correctly. The main drawback is the high costs involved in running both systems.
Pilot: An organization has a certain location test the new system while the entire organization runs the old system. After the new system is verified, the entire organization switches to the new system.
Plunge: The entire organization cuts off the old system and starts running the new system. This is the most cost-effective conversion, but it does not allow for a backup if the new system does not run correctly.
Phased: The new system is installed in phases as it developed. This approach is not unusual when organizations install a large, enterprise-wide system.
Phase 4: Implementation-Training
The users of the new system must be trained. Often, the users who were a part of the development team train their peers on the new system.
Phase 5: Maintenance
addresses any problems and makes modifications as the system is being used, with the input being the either the problem found or the revision requested.
Phase 5: Maintenance Major tasks:
1. Address Problems
2. Resolve Problems
Phase 5: Maintenance Address Problems
When requests to modify the system are received, the system is revised as necessary.
Phase 5: Maintenance Resolve Requests for Revision
When problems or issues arise, they are investigated and solved.
Phase 5: Maintenance Issue Patches
When modifications are needed, updates are created and issued.
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