Chapter 5 - Implementing Computer Based Systems

Chapter 5 - Implementing Computer Based Systems

1. In any project, there are two main people within the project: the client and the developer.

   • It is the client who seeks a new system or an improvement to the current system. At first, they cannot possibly explain what they want fully or in enough detail = therefore client involvement is vital.
   • The client is the customer - the system is being produced for the client - the system must meet the needs of the client - the systems analyst will document the users requirements - the project involves many members at onse - if the customer is not involved then the final system will not match the needs of the client.

2. Client involvement is vital throughout the project.

   • In the definition/analysis stage the client will tell the analyst what they want the system to do (which takes place during the interview) and based on this, a requirements specification will be created. If the client does not specify a requirement, it won't show up on the final system - therefore the clients should be involved throughout to make sure all of their requirements are shown.
   • In the design stage, the client needs to see all of the designs to make sure they are as required. If not then the client can give feedback and rectify the designs to suit the needs of the client.
   • In the implementation/testing stage the developer creates the solution to the problem. Therefore if the client hasn't been involved then the needs of the client will not be met and the problem will not be solved.
   • During the installation stage the client should be consulted on the best method of changeover and appropriate dates for the changeover - this can minimalise errors and disruptions to the company.

3. Off-the-shelf vs. custom written

   • Off the shelf software
     • Disadvantages - has an expensive yearly cost/one off cost, may have to be altered to fit the purpose of the user, will probably have a higher memory footprint than custom due to bloatware.
     • Advantages - discussion groups, books etc. will already exist therefore you can get easy help, the software will be available immediately and you may already be familiar with the HCI.
   • Custom written software
     • Advantages - when you have finished with the software you can sell it to recoup some of the development cost, the system size will be smaller because there isn't bloatware included, there is a choice who writes the software therefore you can get the best price.
     • Disadvantages - will need to hire someone to write the software which could be expensive, you're only likely to get support from the people who developed it - what if they won't support it? and if you forgot a requirement, it won't show up.

4. Overall, the decision to upgrade is based on feasibility. It is necessary to work out whether it is feasible to upgrade the system - based on financial, personnel and technical feasibility.

   • Financial feasibility – most companies aim to make a profit or at least get the best value for money. A cost-benefit analysis will be carried out to work out whether its feasible.
   • Personnel feasibility – is hard/cannot be measured easily. Questions need to be asked such as “will the staff have the expertise to use the new system?”, “will any redundancies have a negative effect on morale?”.
   • Technical feasibility – this also cannot be measured easily. Questions to ask include: “will the existing hardware cope with the planned software?”, “will the new software be compatible with the old hardware?”.
   • A feasibility report will be created highlighting key positives and negatives of upgrading the system.

5. Reviews carry on all of the way through the systems life cycle, and they involve the client and the project team. The purpose of reviews is to ensure the system is doing its job properly, is still running efficiently and is still up to date. People must include representatives who are most familiar with the new system who know the strengths and weaknesses. If reviews are not carried out, then bugs will not be found and the system will not work as efficiently, users could become disillusioned that the system doesn’t work and if the system is not checked for accuracy then data could be compromised.

6. Changeover - is when the installation of a new system takes place. There are four different types of installation methods: parallel, phased, pilot and plunge.

7. Maintenance is part of the systems life cycle. It comes in three different forms: corrective, adaptive and perfective.