The process of monitoring, evaluating, and modifying of existing information systems to make required or desirable improvements may be termed as System Maintenance. System maintenance is an ongoing activity, which covers a wide variety of activities, including removing program and design errors, updating documentation and test data and updating user support. I.e. all activities associated with changing any program, procedures or documentation for
an operational information system to keep the system operating correctly and to adapt to meet the changing requirements of end user.
Causes of system maintenance
1. Environmental changes: – e.g. government tax policies may influence change in a payroll system.
2. Change in user requirements
3. Poor documentation- Makes it difficult for one to understand the system, may be changes in order to improve its maintainability.
Types of maintenance
For the purpose of convenience, maintenance may be categorized into three classes, namely:
A. Corrective Maintenance: This type of maintenance implies removing errors in a program, which might have crept in the system due to faulty design or wrong assumptions. I.e. changes or actions in response to problems or errors and is intended to correct errors in the system that were not detected during design and construction process so as to help keep the system in operation. Thus, in corrective maintenance, processing or performance failures are repaired.
B. Adaptive Maintenance: In adaptive maintenance, program functions are changed to enable the information system to satisfy the information needs of the user. I.e. Changes in the system to accommodate expected changes in the processing environment. This type of maintenance may become necessary because of organizational changes which may include:
• Change in the organizational procedures,
• Change in hardware and software.
• Change in users’ specifications
• Change in organizational objectives, goals, policies, etc.
• Change in forms,
• Change in information needs of managers.
• Change in system controls and security needs, etc.
This change results in additional features and new functions to the system.
C. Perfective Maintenance: Perfective maintenance means adding new programs or modifying the existing programs to enhance the performance of the information system. I.e. enhancement in the system in response to request users. It is intended to improve performance, efficiency and extend facilities to more users or to make the system more user friendly.
This type of maintenance is undertaken to respond to user’s additional needs which may be due to the changes within or outside of the organization. Outside changes are primarily environmental changes, which may in the absence of system maintenance, render the information system ineffective and inefficient. These environmental changes include:
• Changes in governmental policies, laws, etc.,
• Economic and competitive conditions, and
• New technology.
D. Preventive maintenance – Refers to changes in the system structure in order to simplify and
reduce cost of future maintenance
Post implementation review and system maintenance stages are continuous stages and activities which begins from the time the system is implemented to the time it is regarded absolute / decay.
The post implementation review team writes a report that indicates specific areas of the system that need corrected. This report is called post implementation review report or evaluation report. It acts as a reference document during system maintenance.
Importance of Post implementation / Evaluation
1. To verify that the installed system meets the user requirements
2. Provide feedback to development team
3. To justify the adoption, continuation or termination of the installed system
4. To clarify and set priorities for the system for the system development team to the users.