09 System Development Life Cycle (SDLC) Flashcards
Define the SDLC.
A SDLC is “a sequence of activities that are performed when a system is analysed designed and implemented”. This cycle is repeated as the software is updated and improved from time to time.
What are the stages of SDLC?
- Investigation
- Analysis
- Design
- Implementation
- Maintenance
- Evaluation
What four methods does a Systems Analyst use to gather information during the investigation phase?
- Questionnaires given to employees, managers or customers
- Interviews with managers and a few key employees and customers
- Observation of employees doing their normal day-to-day work
- Reading of documents and reports
What is adaptive maintenance?
Adaptive maintenance makes changes to the system to meet the changing needs of the business or organisation. I.e. as a company grows more employees might use the application than was expected. So the system may need more processing power to allow for this.
What is perfective maintenance?
Perfective maintenance improves the performance of the system after it has been implemented. For example, the database developer provides an upgrade that makes queries run faster.
What is corrective maintenance?
Corrective maintenance fixes bugs in the software that were not discovered during testing. For example, the software developer provides security patches that fix vulnerabilities.
How does a Systems Analyst use in-depth interviews during the investigation phase of the SDLC?
The analyst conducts interviews with managers, senior operations staff and the biggest customers and suppliers using both open and closed questions.
What is an advantage of using in-depth interviews during the investigation phase of the SDLC?
Interviews can reveal information the analyst had not considered. The analyst has the opportunity to ask follow-up questions and to request deeper explanation.
What is a disadvantage of using in-depth interviews during the investigation phases of the SDLC?
- Conducting interviews can be time consuming
* Results are qualitative, difficult to analyse and often cannot be represented in charts.
What is an advantage of using questionnaires during the investigation phase of the SDLC?
- Questionnaires are most effective when given to a large number of people, so that quantitative statistics can be produced
- Questionnaires are an efficient way of obtaining information from a large number of employees or customers, especially if they are in different locations.
What is a disadvantage of using questionnaires during the investigation phase of the SDLC?
• Questions are fixed in advance - respondents cannot respond to clarify. Staff may not return questionnaires or not fill them in accurately.
What four aspects should be considered in the design stage of the SDLC?
- House style
- Hardware specification
- Structures (i.e. database tables and fields)
- User interface
- Output reports
- Networks
- Staffing issues
- Security processes
A Systems Analyst has four choices of changeover strategy when a new IT system is introduced. Name them.
- Direct changeover
- Parallel changeover
- Phased changeover
- Pilot changeover
State an advantage and a disadvantage of direct changeover strategy.
- Advantage - Simplest and least costly
- Disadvantage - High risk. If new system doesn’t work perfectly the first time the company could face serious financial consequences.
State an advantage and a disadvantage of parallel changeover of IT systems.
- Advantage - Lower risk. If the new system doesn’t run properly, the old system is still running.
- Disadvantage - Cost of running two infrastructures may be high. Also, data must be entered and processed in two locations which is inefficient.
State an advantage and a disadvantage of phased changeover.
- Advantage - IT consultants are able to deal with a smaller number of issues as they arise
- Disadvantage - Only an option if the system can be broke down into modules.
State an advantage and a disadvantage of pilot changeover.
- Advantage - Lowers risk so if something goes wrong it only affects one location.
- Disadvantage - Takes the longest to implement and the system isn’t being tested at full scale.
Describe direct changeover of IT systems.
Direct changeover means the old system is switched off as the new system is powered up.
Describe parallel changeover of IT systems.
Parallel changeover means the new and old systems are run at the same time until the new system is ready to take over.
Describe phased changeover of IT systems.
Phased changeover means individual modules of the system are implemented one at a time
Describe pilot changeover of IT systems.
Pilot changeover means the system is tested in one or a few locations rather than in the whole company.
“A sequence of activities that are performed when a system is analysed, designed and implemented.” is the definition of what?
System Development Life Cycle (SDLC)
Analysis is which stage of the SDLC?
Second
Evaluation is which stage of the SDLC?
Sixth
Maintenance is which stage of the SDLC?
Fifth
Implementation is which stage of the SDLC?
Fourth
Investigation is which stage of the SDLC?
First
Design is which stage of the SDLC?
Third
What are the four methods used to gather information?
- Questionnaires
- Interviews
- Observation
- Documentation
Questionnaires, interviews, observations, and documentation are used during which stage of the SDLC?
Investigation.
What method is most effective when given to a large number of people, so that quantitative statistics can be produced?
Questionnaires
What is an effective way of obtaining information from a large number of employees or customers?
Questionnaires
What can reveal information the analyst had not considered?
In-depth interviews.
What can be time consuming if done in-depth?
Interviews
What qualitative results can be difficult to analyse and often cannot be represented in charts?
In-depth interviews
Questions being fixed in advance meaning respondents cannot respond to clarify the questions is a disadvantage of what?
Questionnaires.
What fixes bugs in the software that were not discovered during testing?
Corrective maintenance.
What makes changes to the system to meet the changing needs of the business or organisation?
Adaptive maintenance.
What improves the performance of the system after it has been implemented?
Perfective maintenance
House style is an aspect that should be considered in what stage of the SDLC?
Design stage
Hardware specification is an aspect that should be considered in what stage of the SDLC?
Design stage
Structures is an aspect that should be considered in what stage of the SDLC?
Design stage
User interface is an aspect that should be considered in what stage of the SDLC?
Design stage
Output report is an aspect that should be considered in what stage of the SDLC?
Design stage
Networks is an aspect that should be considered in what stage of the SDLC?
Design stage
Staffing issues is an aspect that should be considered in what stage of the SDLC?
Design stage
Security processes is an aspect that should be considered in what stage of the SDLC?
Design stage
Direct changeover is a method used when?
A new IT system is introduced
Parallel changeover is a method used when?
A new IT system is introduced
Pilot changeover is a method used when?
A new IT system is introduced
Phased changeover is a method used when?
A new IT system is introduced
The old system being switched off as the new one is powered up is the description of which changeover method?
Direct changeover
New and old systems being run at the same time until the new system is ready to take over is the description of which changeover method?
Parallel changeover
Individual modules of the system being implemented one at a time is the description of which changeover method?
Phased changeover
The system being tested in one or a few locations rather than in the whole company is the description of which changeover method?
Pilot changeover
Which changeover method is the simplest and least costly?
Direct changeover
Which changeover method runs at lower risk so if the new system doesn’t work, the old one is still running?
Parallel changeover
Which changeover method means IT consultants are able to deal with a smaller number of issues as they arise?
Phased changeover
Which changeover method lowers risk so if something goes wrong it only affects one location?
Pilot changeover
Which changeover method is of the highest risk so if the new system doesn’t work perfectly the first time the company could face serious financial consequences?
Direct changeover
Which changeover method is the most expensive due to running two infrastructures at the same time?
Parallel changeover
Which changeover method is only an option if the system can be broken down into modules?
Phased changeover
Which changeover method takes the longest to implement?
Pilot changeover
Which changeover method is the least efficient as data has to be entered and processed in two locations?
Parallel changeover
Which changeover method means the system isn’t being tested to its full scale?
Pilot changeover.
