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1. The Systems Development Life Cycle (SDLC)
2. The Systems DevelopmentLife Cycle (SDLC): A series of steps completed over a period of time by analysts in a system development or maintenance project.
3. System Life Cycle: Embodies the entire life span of a system. In this text, life cycle will refer to project life cycle, unless indicated otherwise.
5. Logical and Physical Design: The logical design provides the user's view of the system, while physical design specifies the actual way the system will be implemented.
Logical design specifies the desired logical assembly of the system relative to what it will do and why, while physical design specifies how to physically implement the logical design.
6. Frederick Taylor's Scientific Management to Solving Problems: Define the Problem.
Identify Alternative Solutions.
Evaluate the Alternatives.
Implement the Selected Alternative Solution.
7. System Development and Maintenance Life Cycle: Problem Definition.
System Analysis and Feasibility Study.
Installation, Conversion, and Training.
System Modification and Enhancement.
8. Problem Definition: Problem definition is performed by the analyst to identify the central purpose for the SA&D project.
9. Types of Problems: Omission.
10. System Project Request: The problem usually comes to the attention of the systems analysis staff either through a formal systems request or direct communication with affected users.
12. Feasibility Study: A study to determine if a systems analysis and design project is both operationally and economically feasible. A more detailed operational/economical feasibility study is performed as more information is acquired concerning the project.
13. Operational Feasibility: Refers to having a project that can be completed operationally, or completing a system project that develops a system that the company can operationally support.
14. Economical Feasibility: Refers to having a project that can be completed based on considering the financial costs of completing the project versus the benefits of completing it.
15. Documentation: Creating detailed descriptions and explanations for all the components of systems and their use from the perspective of both a designer/developer and a user.
16. System Analysis andDesign Documentation: Designer/developer documentation which provides a "bird's-eye" view of the system to allow the project team to track the development of the project. This documentation becomes a permanent record for the completed system. All facts gathered and recorded become part of the development.
17. User Documentation: A general explanation of the system.
Detailed explanations of what is required of users in employing the system.
Detailed explanations of the results of system executions.
18. User Requirements Documentation: Documenting the information needs of people in the business produces the user requirements from which systems are constructed.
19. User Requirements using E/RD and DFD Modeling Methods: Are one way to standardize the creation of user requirements.
By standardizing the creation of user requirements and other system documentation, a company makes it easier for someone with knowledge of one system to gain a working knowledge of another.
20. Design Dictionary: A comprehensive collection of the design specifications used to define and describe all the components specified in designing a system.
The design dictionary becomes an extremely valuable source of information because it permits another analyst to gain comprehensive knowledge of the system.
21. Three Basic Alternativesto Solving the Problem: Modify the existing system.
Replace the existing system by developing a new system.
Replace the existing system by purchasing a new system.
22. Replacing the Existing Systemby Developing a New System: No software vendor supplies a system of the type needed.
An appropriate vendor-supplied system is deemed too costly.
A vendor-supplied systems would require far too much customization for it to match the needs of the users.
The firm does not have the available staff required to complete the system project.
23. Replacing the Existing System by Purchasing an Available Vendor-Supplied System: An existing vendor-supplied system will cost effectively meet user's needs, and
The firm does not have available staff to complete the project.
24. Three Alternative Perspectives that Existfor Each of the Three Alternative Solutions: The pessimistic (conservative) solution.
The most likely (middle of the road) solution.
The optimistic (liberal) solution.
These solutions suggest answers to the "what if" questions that assume either:
The worst possible outcome.
The most likely outcome.
The best possible outcome.
25. Logical Design: Consists of a logical series of operations necessary to meet user's new or additional information needs with little regard for physical implementation.
Logical design focuses on WHAT the user needs with little, if any, consideration for HOW that need can be met through physical circumstances.
26. Logical Design Models: During logical design, the analyst often creates a model of the proposed system that shows the user what the system will look like, what it will do, and what outputs it will generate.
27. Physical Design: Embodies an expansion of the logical design that includes the details of software and hardware that give physical reality to the logical design.
Physical design is devoted to creating specifications that establish the physical environment within which the system will operate, the physical characteristics of the system, and how it will physically function.
28. Steps in Physical Design: Identify resources needed to meet user needs.
Identify procedures necessary to meet user needs.
Describe the procedures so that computer code can be generated.
Describe data so that stored data can be created or modified.
Identify additional technology necessary for the new or modified system.
29. System Development(Design Implementation): Involves creating the separate modules that compose the system consists and their integration with other software into a harmonious system.
30. Structured Analysis and Design: Dictates that modules be designed and developed as separate components that are integrated to produce a harmoniously performing system through the creation of various interfaces, the sharing of data, and limited task sharing.
31. System Testing: Testing the separate modules and the integrated system.
Types of Testing:
32. Types of Errors: Syntax Errors:
Occur when a programmer does not follow the rules (grammar) of the specific software language or they misspell or misuse key-words (vocabulary) of the language.
Occur if the output does not precisely conform to the requirements specified for that component of the system, even though the program passes all syntactical checks.
Involves testing all of the logical procedures through a program's logic.
33. System Implementation Activities: System installation.
34. Installation - Conversion - Training: All have a transitional nature; they transition into having the system in production, conversion of data, storage, etc., and training on the use of the new system and accompanying practices and technology.
35. System Installation: Immediate change-over.
36. Conversion: The practice of modifying existing data, data storage, software, and hardware to fit a newly modified or developed system.
37. Reusable Code: Refers to existing software modules that can be reused in new or modified systems, although they often need conversion into a new format.
38. Training: Essential if they are to use these new system acquisitions effectively.
Usually involves both in-house courses and external seminars.
Includes how to use the new system and interpret its output.
New systems require users to become acquainted with screen-formatted data entry, responses to system generated screen prompts, and new reporting methods.
39. System Project Formal Review: Consists of upper-level and lower-level management and system professionals responsible for evaluation of project results.
40. System Project Modificationand Enhancement: New or modified systems usually some modifications and enhancements immediately following the formal review phase of the project.
41. System Maintenance: Involves modifying the design of the system and developed programs to provide for the needs of the users.
Although system maintenance may not be considered a part of the SDLC, it is a part of the life cycle of a system.
42. SDLC - Logical and Physical Modeling - Modeling Methods: Life Cycle Phase Logical/Physical Modeling Methods
Problem definition Logical Analysis modeling methods
System analysis and Logical Analysis modeling methods
Logical design Logical Logical modeling methods
Physical design Physical Physical modeling methods
Development Physical Physical modeling methods
System testing Physical Physical procedures
Installation conversion Physical Physical procedures
Formal review Physical Physical evaluation
System modification Logical/Physical Logical/Physical modeling
and enhancement methods/procedures
43. System Project Management: Using project management principles to manage the significant amount of the firm's resources (personnel, materials, facilities, etc.) mobilized by an A&D project in the most efficient and valid manner.
Project Master Schedule:
A schedule used to track the actual completion of portions of the project.
44. Types of System Projects: Reactive System Development Project:
A project that originates as a reaction to changes in the business environment.
Proactive System Development Project:
A project that anticipates positive modifications in the firm's operations and systems that are planned by key personnel in the firm.