Topic 9 System development life cycle Flashcards Preview

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Flashcards in Topic 9 System development life cycle Deck (17):
1

System Development Life Cycle Phases (6)

Feasibility Study
Analysis/Investigation
Design
Implementation
Changeover Methods/ installation
Maintenance Phase

2

Feasibilty report

The summary of an initial investigation to look at the likelihood of being able to create a new system

3

What should a Feasibility report/ investigation include (6)

User requirements (aims and objectives)
Cost benefit anlaysis of the new system
Details of existing hardware and software
Conclusion
Benefits of the new system
Identification of problems with the current system

4

Reasons why a new system could be required (4)

Failure to supply users with the information they require
The cost of user support is too high
Too much time spent updating the new system
There are security breaches which were not envisioned when the system was first developed

5

BOT (Feasibility)

Budget
Objectives
Time

6

TELOS (Feasibility)

Technical
Economic
Legal
Operational
Schedule

7

Methods of investigation (4)

Interview
Observation
Questionnaires
Document Inspection

8

Features of a process that could be considered when designing a system (4)

Design of input methods
Design of processes
Design of output
Security procedures

9

4 types of changeover

Direct changeover
Parallel changeover
Phased conversion
Pilot conversion

10

Direct changeover

Stop using the old system one day and start using the other
Risky
If the system fails it can end badly for the business
Requires fewer resources and is simple, provided nothing goes wrong

11

Parallel changeover

Old ICT system is being used alongside the new ICT system until the management is happy that the new system is working correctly
Minimises risk
Can compare results to ensure that the new ICT system is working correctly
Lot of unnecessary work and therefre expensive in people time
Adds the amount of planning needed for the implementation

12

Phased conversion

A module at a time is converted to the new system until the whole system is transffered

13

Pilot conversion

One branch at a time

14

3 methods of maintainance

Perfective
Adaptive
Corrective

15

Perfective

Improving the performance of the software

e.g. modification of user interface upon feedback from users who are finding it difficult to use

16

Adaptive

Software may need to be changed owning to the changing needs of the business

e.g. A new virus threat/hacker threat means that the software will need to be adapted to protect against this

17

Corrective

Bugs in the software which were not discovered during testing may need correcting

e.g. A piece of software may crash when being used with another piece of software