Implementation

Implementation is the process of constructing the working computer system. It will usually include:

  • Identifying the modules to be used and specifying them
  • Identifying the main data structures within the program
  • Identifying the main algorithms to be used, describing them in pseudo code or as structure diagrams
  • Producing the program and any other elements of the system

Purpose:

  • Process of creating a working computer system based on previously produced system design documentation
  • Implementation usually incorporates tasks such as determining the actual data structures to be used to store the data once it is input, specifying individual system modules and describing them in algorithmic form before actually creating the computer system and its associated elements

Installation is the process of starting to use an information system in a real situation after having designed and developed it. It may enable final testing in a real situation. Different approaches are used depending on the size of the system and the properties of the data being produced

Changeover: Following the design, implementation and testing of a new information system a changeover from the old to the new system must take place; this allows the information system to be tested in a real life scenario if necessary. During Changeover: Hardware is installed, the software is installed, data conversion takes place, an appropriate changeover method is used (Direct, parallel, pilot, phased), training completed in operation of new system

Parallel running requires the new system to operate for a short period of time alongside the older system. The results can be compared to ensure that the new system is working correctly

Direct changeover requires that the new system replaces the old system without any overlap. In some cases direct changeover is the only option.

Pilot running requires the new system to operate alongside the old system but only processing part of the data. The results can be compared to check that the new system works correctly but pilot running cannot test how the system will operate with the larger quantities of data of the real situation

Phased implementation involves replacing part of a system with a new system while some tasks continue to use the old system. this enables training and installation to be carried out over a period of time

Documentation: All systems will be provided with a series of documents used to, support the planning and development of the system, support in the maintenance of the system and supporting the end user as they use the system.

User documentation gives the user any information necessary for the successful running of a piece of software or hardware. This does not generally include many technical details, which will usually be found in technical/ maintenance documentation

Technical documentation describes how the system works. It is written for the computer professional rather than the user. The reader will need to have expert knowledge. It will include system documentation, program documentation and maintenance documentation.

System documentation describes the results of the system analysis, what is expected of the system, the overall design decisions, the test plan and test data with the expected results.

Program documentation is the complete description of the software, intended for use when altering or adapting software. it usually includes a statement of the purpose of the software, any restrictions on the use of software, the format for input data, printed output produced, flowcharts, program listings and notes to assist in future modifications

Maintenance documentation is parts of the document which are used to later develop and adapt the system

Data conversion is the process of transferring or converting data from the old system to the new one

Maintenance is ensuring the system continues to run smoothly and to meet changed requirements

Program maintenance is the modification of a software application or system after its implementation has been completed. There are various types of program maintenance

  • Corrective Maintenance: This may be needed to correct errors found in the system
  • Adaptive Maintenance: May be necessary to adapt the system to changes within the organisation using it, to external changes such as new legislation or to allow the system to operate with new hardware
  • Perfective Maintenance: Making changes that may be advantageous to enhance the performance phase of the system

Ease of Maintenance allows modifications that have to be made during the life of a system to be carried out easily and cheaply
Program maintenance enables software to be designed in a way that enables ease of maintenance

Adaptive Maintenance it may be necessary to adapt the system to changes within the organisation using it, to external changes such as a new legislation or to allow the system to operate with new hardware

Corrective Maintenance is needed to correct errors found in the system post installation

Perfective Maintenance is making changes that may be advantageous to enhance the performance of the system