Topic 9: System Development Life Cycle (SDLC) Flashcards
Define the System Development Life Cycle
A System Development Life-Cycle 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 the SDLC? (in order)
Investigation Analysis Design Implementation Evaluation Maintenance
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 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 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 phase of the SDLC?
Conducting interviews can be time consuming.
Results are qualitative, so they are difficult to analyse and often cannot be represented in charts.
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 is adaptive maintenance?
Adaptive maintenance makes changes to the system to meet the changing needs of the business or organisation. For example, 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 four aspects should be considered in the Design stage of the SDLC?
House-style
Hardware specification
Structures (such as 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 a direct changeover strategy.
An advantage of direct changeover is that it is the simplest and least costly method.
A disadvantage of direct changeover is that it is high risk. If the new system doesn’t work perfectly first time the company could suffer serious financial consequences.
State an advantage and a disadvantage of parallel changeover of IT systems.
An advantage of a parallel changeover is that it is lower risk. If the new system doesn’t run properly, the old system is still running.
However, a disadvantage is the cost of running two infrastructures. Also data must be entered and processed in two locations, which is inefficient.
