Chapter 5: Implementing Computer-Based Information Systems Flashcards
Give 3 reasons why it is important the client is involved during the development of a custom-written system?
- They will provide details of what the new system should do
- If details are incomplete, the client can expand on the requirements to prevent loss of money and time
- They can be consulted at all stages to prevent errors
What is a cost-benefit analysis?
Analysis of the cost effectiveness of different alternatives to see whether the benefits outweigh the costs
In the cost-benefit analysis, give 3 costs that should be considered?
- Skills and training to learn how to operate the new hardware and software
- Licences for the new software
- Hardware needs to be upgraded to meet new requirements
Give 2 advantages of off-the-shelf software?
- Immediately available to install and use
2. Lots of help and support available online from other users
Give 2 disadvantages of off-the-shelf software?
- Not unique and therefore may not meet specific requirements
- Costs a lot to buy and install on each computer
Give 2 advantages of custom-written software?
- End user owns the software and can sell it to make money
2. Fits the requirements exactly
Give 2 disadvantages of custom-written software?
- Not much support as only the developers will know how to use it
- Takes a long time to develop
What are the 4 installation methods?
- Parallel
- Pilot
- Phased
- Direct
Describe what happens in parallel installation?
The old and new systems are run at the same time. The old is only discarded when accuracy and reliability are confirmed in the new system
Describe what happens in pilot installation?
Only selected sections use the new system to build confidence to use it for more and more tasks until they all have been completed
Describe what happens in phased installation?
Different systems in the organisation are brought online one by one using the new system until they are all using it
Describe what happens in direct installation?
The new system completely replaces the old system in one go
Give 1 advantage and disadvantage for parallel installation?
Advantage
1. Problems can be found in the new system and rectified whilst the old system takes over
Disadvantage
1. Data is duplicated so inconsistencies have to be checked twice
Give 1 advantage and disadvantage for pilot installation?
Advantage
1. Problems can be found with the new system before the next stages are implemented
Disadvantage
1. Implementing the new system can take a long time
Give 1 advantage and disadvantage for phased installation?
Advantage
1. If a problem is found the organisation can still use the old system
Disadvantage
1. Expensive in terms of time and cost
Give 1 advantage and disadvantage for direct installation?
Advantage
1. Cheapest in terms of time and cost
Disadvantage
1. Problems may lead to complete loss of data
Explain in 3 points, the role of reviews during the life of a computer-based information system?
- Reviews can be scheduled to occur regularly or with any planned external or internal changes
- Reviews enable hardware and software developments to be incorporated into the system
- During reviews users should be asked for views on how well they think the system is working and their feedback noted
In role of reviews, what are external changes?
Legislation changes such as TAX and VAT
In role of reviews, what are internal changes?
A change in the mode of operation were new functions performed by the system need to be included
What are the 3 maintenance methods?
- Corrective
- Adaptive
- Perfective
Describe 3 characteristics of the maintenance method Corrective?
- Also known as remedial maintenance
- Used if there any errors in the software
- The bugs can be either programming or logic
Describe 2 characteristics of the maintenance method Adaptive?
- Only occurs when the organisation has a new requirement the system must fulfil
- Or, the system needs to be adapted due to internal or external changes within the organisation
Describe 1 characteristic of the maintenance method Perfective?
- Only occurs when theres benefits to enhance the performance of the system or to make it easier for the end user to operate
Give 1 reasons for the need for Corrective maintenance?
- Errors not spotted in testing before becomes obvious
Give 2 reasons for the need of Adaptive maintenance?
- Security issues may arise so the system will need more protection
- New hardware or software may be purchased which needs to be implemented into the system
Give 3 reasons for the need of Perfective maintenance?
- Rewriting procedures to reduce the response time of the system
- Tasks not included in the design stage need to be added to the system
- Addition of short-cut keys to help users shorten processes
