Chapter 10 Flashcards
What do system failures cause?
- Missed deadlines
- Users’ needs not addressed
- Poor support from top management
What do successful information systems integrate into their design?
People
Software
Hardware
What is a SDLC?
- Range of clearly defined - phases executed in order
- Serves as framework for development of cycle or project
- Waterfall model
What is the lifecycle of Systems Development?
1.Planning
2. Requirements gathering and analysis
3. Design
4. Implementation
5. Maintenance
What is planning?
Most important phase
Designer understands and defines organisation’s problem
How is information on a problem obtained?
forming a task force
feasibility studies
What is the thought process to take place during planning?
- Identify potential systems in organisation
- Perform preliminary analysis of needs and define problem
- Perform feasibility studies
- Decide to proceed with model or not
What questions do analysts use to assess current and future needs?
- Why system is being developed
- Who are the current and future users
- Is the system new/upgrading/extension of current system
- Which functional areas are going to use the system
What is the information to consider during planning (needs analysis)?
- Organisation’s strategic goals
- How proposed system will support these goals
- Factors critical for the success of the proposed system
- Criteria for evolution of proposed sysytem
what representatives are required for the task force during planning?
IT department
Systems analysts
Technical advisors
Top management
Planning: Task Force; Joint program design?
- Collective activity existing of task force members
- Structured workshop where everyone comes together to develop program
- Detailed agenda; Visual aids; leader
- Result in final document containing definitions of planned system
=Internal users: Employees who use system regularly
=External users: non-employees who will use system
Planning user feedback: 4W’s?
Why is the system designed
Who will use the system
When will the system be operational
What kind of capabilities will the system provide
What is the feasibility studies area of planning?
Analysis of the proposed solutions’ feasibility and determine how to present solution to management
Feasibility studies are measured against how advantageous and practical system will be for organisation
Measured continuously through SDLC proses
What are the 5 dimensions of feasibility studies?
Economy
Technical
Operational
Scheduling
Legislative/Legal
What is Economic feasibility?
Assess system cost and advantages
Advantage>Cost = Economic feasible
What is technical feasibility?
technology used in the system
1. Is technology available
2. Is it feasible to implement
What is operational feasibility?
Assess how the proposed solution will work for the organisation
Measures how internal and external users would react to system
Assess whether it is worth it to implement the system
Scheduling feasibility?
Determine if the system will be finished on time
Is system will not finished on time and clients will be lost as a result thereof - System not feasible
What does legal feasibility entail?
Determine legal/legislative aspects and address the following:
-Will system violate any legal issues in country of use
-Are there political repercussions
-Is there conflict between the proposed system and legal requirements
What are the requirements gathering and analysis?
Analysts define the problem and generate alternatives to solve the problem
Information gathered by means of:
-Interviews
-Recordings
-Observations
What is information used for in the second phase?
Processing analysis: What the system should do
Data analysis: Which data is needed for the process to be executed
What are the two approaches for analysis and design of information system?
- Structured system analysis and design => SSAD
- Treat processing and data independently
- Sequential approach
- Requires completion of analysis before starting with design - Object oriented approach
- Combines processing and data analysis
- Analysis and design is done in 1 phase instead of 2 phases
What types of designs to analysts opt for?
-Most Realistic
-Offers highest reward
What are the 3 parts of the design phase?
Conceptual design
- Overview of system
Excludes hardware and software
- Logical design
Specifies hardware and software - Physical design
Design for specific platform
What is Computer-Aided Systems Engineering?
(CASE)
Systems analysts use aids to automate certain parts of application development process
Tools are helpful in investigation and analysis of large-scale projects
Analysts use this to make modifications and updates to several design versions to get best version
What does CASE Aid in?
Helps Analysts to:
- Keeps models consistent
- Documents models with explanations and notes
- Ensures models are developed according to rules
- Keeps record of and maintains changes to design
- Creates different versions of design
What is design prototyping?
Small scale version of system is developed
Big enough to illustrate advantages of system
Users can give feedback on system
Possible problems identified and solutions investigated
Why is design prototyping used?
- Collects system requirements
- Helps to determine system requirements
- Determine technical feasibility of system
- Sells the proposed system to users and management
What is a Proof-of-Concept?
Shows users how a task that was previously impossible can now be performed.
Selling Prototype?
Used to sell proposed system to users and/or management by illustrating some of its functions
What are the steps to design prototyping?
- Define initial requirements
- Develop prototype
- Review and evaluate prototype
- Change prototype
What does the implementing of a system entail?
Solution transferred from paper to action
System is configured and components are produced
What are the types of system conversions?
Parallel
Phased - in - phased - out
Plunge
Pilot
Parallel Implementing?
Old and new systems run simultaneously for short time to ensure new system works
Very expensive and can only be used if operational system is already in place
Phased-in-phased-out Implementing?
Each module is phased in and the old one phased out until the whole system is operational
Not suitable for all situations
Can be effective in accounting and finance
Plunge Implementing?
Stop the old system and start using the new one
Very high risk (if there are problems with new system), but cost effective (Higher risk, higher returns)
Pilot Implementing?
New system is only introduced to limited area of organisation
If it functions like it should, it is implemented in the rest of the organisation (either in stages or all at once).
What tasks need to be performed for implementing to take place?
Purchase of new equipment
Appointment of new employees
Training of employees
Planning and design of physical layout
Coding
Testing
Design security measures and safeguards
Create a disaster recovery plan
What is a request for proposal?
Written document with detailed specification used for bid for equipment, supplies or services
Contains detailed functional, technical and business requirements information
Compares different bids
Convenient to use single vendor to supply all components
(Consider that the vendor might not have knowledge for all areas of business)
What are alternatives to implementation?
Insourcing
-Organisation’s team develop system internally
Self-sourcing
-End users design own system with minimum or no input from IT
-Might not have knowledge to write programming code
-Proficient enough to use off the shelf software
-Manufacture custom-made applications
Outsourcing
-Organisation appoints external supplier or consultant who specialises in development services
What does Maintenance entail?
System is in use
Improvements and modifications are developed and tested
Hardware and software are added or removed
Maintenance team assesses how the system works and take actions to ensure the system keeps working
If system objectives are not being met, corrective action will be taken
