Quiz1 SDLC & Prototyping

Question 1

Advantages of prototyping

Answer 1

Advantages:
It’s easy to see what functionality is missing from the demo
It encourages innovation and flexible minds as new ideas can be easily tested
It requires validation to work, hence discrepancies can be easily identified.

Question 2

Advantages of system development life cycle

Answer 2

Advantages:
• Highly structured with well-defined goals and timelines
• Encourages documentation
• Effort spent in planning may save effort/time later
• Projects and progress are easily understood from the outside
• Well-suited to projects using established technologies/standard requirements

Question 3

Disadvantages of prototyping

Answer 3

Disadvantages:
Requirements for the product may change significantly after reaching build, creating more work (Cyberpunk)
Identified non-functional elements may be difficult to document from the demo
The client may be unaware or uncertain about what they’re looking at or what they want.

Question 4

Disadvantages of system development life cycle

Answer 4

Disadvantages:
• Requires the customer to know in advance exactly what it is that they want
• Not suited to high-risk or experimental projects
• High documentation requirements can be onerous on individual developers
• Changes to requirements require revisiting each stage of development
• Very formal

Question 5

Phase 1

Answer 5

○ Phase 1: Preliminary Analysis
		○ Technical Feasibility
			• Can I do it?
			• Confirms system will work with no production barriers
		○ Operational Feasibility
			• Can I do it?
			• Can it solve problem at hand?
			• Takes advantage of the opportunities identified by scope definition
		○ Economic Feasibility
			• Can the money do it?
			• Will it make a load of cash?
		○ Human Factors Feasibility
Is it relevant, and can target audience use it?

Question 6

Phase 2

Answer 6

○ Phase 2: Analysis
○ Model of current system
• how does the system work now → see everything (how do people work, see files etc)
• gather info: interviews etc
• identify target audience
• model processes using ER diagrams and DFDs
○ Define objectives of new system
• what do users need?
• use info to get objs
• goals: what do u want to do
• what inputs are needed to make required output
• create logical design of new system: process modelling: DFD, ER modelling or object modelling: use case & class diagrams → design phase
• find a solution
-finalize project plan

Question 7

Phase 3

Answer 7

○ Phase 3: Design → physical and logical design
○ Logical
• abstract design usually by modelling. Eg Entity relationship diagram
○ Physical
-specs on coding

Question 8

Phase 4

Answer 8

○ Phase 4: Development
○ Obtain and Install Hardware
• Find suitable vendors able to supply and support hardware
• Negotiating purchase or lease of hardware including contracting for ongoing vendor support in case of damage, loss or malfunction.
• Testing and evaluating vendor proposals,
• Making a decision
• Obtaining installing and testing hardware
○ Setting up a Development Environment
• Database server
• Application server
• Web server
• Hardware & Network infrastructure
• Create a database
• Create a database server
• Obtaining a database engine (MySQL, SQL server etc) and creating the back end (tables, relationships, stored procedures) specified in ER Diagrams & Normalisation
• Setting up security on database
○ Coding and Customizing Software
• Design algorithms. Pseudocode, DFD’s, Structure Diagrams, Flow Charts
• Coding all modules identified in Structure Charts and DFD’s and minutely specified in pseudocode, flow chart etc.
• Customising any off-the-shelf software.
• Alpha testing is done as code is written
○ Testing the System
• Setting up a Testing environment
• Install Hardware & Network infrastructure
• Boundary testing
• White box & black box testing
• Load testing
• User acceptance testing
○ Begin Documenting the System
• User documentation. Help files, Online help, FAQ’s
• System documentation. ER diagrams, DFD’s Data dictionary, Comments in programming code, Help files for system administrators, online help for administrators

Question 9

Phase 5

Answer 9

○ Phase 5: Implementation
○ Direct Changeover
• Suddenly switch everyone over to the new system.
• Cheapest option if it works.
• Risk for errors are high.
○ Phased Implementation
• Gradually introduce discrete aspects of the new system over time.
• Users learn the new system, can cope with changes, problems can be managed.
○ Parallel Changeover
• Run new and old system simultaneously till you’re sure the new system works.
• Requires a lot of extra work from the users – need to do everything twice.
• May need to employ a bunch of temps to handle double workload.
○ Pilot Changeover
• A small number of competent users try the system first
• Everyone else stays on the old system till all bugs have been sorted.

Question 10

Phase 6

Answer 10

○ Phase 6: Evaluation and Maintenance
○ Is it working? Does it fit the pre-analysis stuff?
○ Operation, Support and Security
• The purpose of this phase is to provide ongoing assistance for an information system and its users after the system is implemented.
• Debug errors as they are reported, code fixes for security holes as they are identified.
• Issue regular updates which include recent security holes and bug fixes, and may include new or enhanced features in the software.
• Occasionally issue a new release or new version of the software where sufficient changes in core code warrant it. A new Word release could be Word 14.

Question 11

Context Diagrams

Answer 11

○ Context Diagrams
○ Showing outside the system to inside
Shows no processes

Question 12

Data Flow Diagram

Answer 12

○ DFDS
○ Shows processes in the system
Entities to processes