System testing and installation planning
The "implementation stage" confused with the "installation stage".
You are likely to come across descriptions of the Systems Life Cycle in various books and online that include references to an "implementation stage", which the writers then manage to confuse with an "installation stage". Implementation is concerned with taking the design produced in the design stage and turning it into a real, actual working system. It means building the system from the design documents This is not the same as "installation". Installation is taking the finished, built and tested product from the design company’s premises and putting it into the customer’s premises, ready to be used.
The Testing stage
Thorough testing should be carried out once the system has been built. It should follow the test plan produced in the Design stage. All results should be documented and cross-referenced just in case there is a problem in the future, to prove that they have been carried out properly and thoroughly. Ensuring that a system works is very important.
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- A company that builds systems has a reputation to protect. They do not want to damage this by producing products that get into the news for the wrong reasons! In some cases, it could cause the company to go bust.
- They need customers to say good things about the product they bought because 'word of mouth' will generate new business. This will help the company make bigger profits
- A system that is unreliable will soon be avoided by users. They will find it frustrating to use and will stop using it. Their company can only suffer because they have invested a lot of money in a system that was supposed to bring benefits and a system that doesn't work often makes matters worse.
- A system that causes accidents will leave a company open to legal action.
The installation stage
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- Once a product has been built and tested in the system designer's buildings, it then needs to be installed in the customer's buildings in a way that ensures minimum disruption to the business. Excellent planning is essential to install a new product with the minimum of disruption.
- Staff training on the new system must take place. This should include those who will use the system and those who will support others in the initial phases of installation, for example the Network Administrator or the various managers. This has implications for the business. If staff are training, they are not working! The cost of this should be taken into account when the project is planned.
- When a new system is to replace an old system, the data files kept on the old system needs to be transferred. Someone has to actually do this and this takes money, time and resources. In addition, any data transferred to the new system should be current. It would be of little use to transfer data from the old system to the new system one day but then not use the new system for a week. There would be one week's worth of data out-of-date!
The hardware and software must be in place. Any additional hardware and software must be bought and stored somewhere until they are installed. They then need to be set-up and checked
There are 4 installation strategies that could be used. These are:
- parallel running
- pilot running
- direct changeover
- phased implementation.
Parallel running
The new system is run alongside the old system. Both systems operate together. This allows the new system to prove itself before the old system is abandoned - data generated by the new system can be compared to data generated by the old system. It also means that staff can be trained and gain confidence in the new system. Of course, if you are running two systems together, that means twice as much work for everyone for a short time!
Pilot running
According to the BCS, pilot running is when the new system is run alongside the old system, but only a portion of the data is actually used in the new system. This method is less of a drain on resources. Data from part of the new system can be compared with the old system, but you cannot check how the whole system will react until you have got the whole system up and running. The term pilot running can also be applied when a system is to be installed in a chain of stores e.g. when a new store accounts system is to be installed in each of twenty stores in a chain. The whole system will be put intro one store and piloted. When it has proven itself, it will be rolled out to other stores, one at a time.
Direct changeover (Big Bang)
The old system is stopped and the new system is started. This might happen over a weekend, for example. If something goes wrong with the new system, then it has to be sorted out because you cannot fall back on the old system. Staff training needs to take place in advance with this method.
Phased implementation
Parts of a new system completely replace parts of an old system, whilst the old system continues to be used as required. The part of the new system that has been installed can be used for staff training and can prove itself before the next part of the installation takes place. This method takes longer than the direct changeover method. A company with 10 branches may install a new accounting system in one branch first, for example. They run it in the branch until it has proven itself and possibly bring in staff members from other branches for training. Once the system has proven itself in one branch, it can then be phased into the other branches.