Perfective maintenance .adds enhancements to an operational system and makes the system easier to useb. diagnoses and corrects errors in an operational systemc. involves changing an operational system to make it more efficient, reliable, or maintain-abled. requires analysis of areas where trouble is likely to occur in order to avoid problems

Involves changing an operational system to make it more efficient, reliable or maintainable

Explanation:

Lientz and Swanson in the late 1970s caried out a survey and categorized maintenance activities into four:

Preventive Maintenance- This is maintenance carried out to prepare for potential changes or pereived changes. Errors are anticipated and measures are taken to ensure these errors are mitigated before they occur.

Perfective Maintenance - as far as maintenance is concerned, the perfective maintenance is described as the biggest because it involves significant changes to the usability and functionality of an operational system simply to make it more efficient and more reliable. Perfective maintenance are forms of redesigns, tweaks that will change the way a system looks or works. Unlike the preventive system, no issues or challenges are pre-meditated, the maintenance is simply to make a good system better.

Corrective Maintenance - This type of system maintenance is carried out after errors have been reported. It is a maintenance system that seeks to diagnose reported errors and fix them as well. These errors are mostly reported errors by users of such systems not the administrators of the system.

Adaptive Maintenance - This is maintenance undertaken to modify a system and ensure it is able to cope with changes in the environment. Meaning, a system that was good before, needs to adapt to new factors in its environment or it becomes obsolete.