Operating system parameters are settings or values that affect the behavior or performance of the operating system1. Modifications to the operating system parameters may be necessary to improve the system functionality, security, or efficiency. However, such modifications may also introduce risks or errors that can affect the system stability, compatibility, or integrity. Therefore, modifications to the operating system parameters should be authorized and documented by the appropriate authority2.

A change control log is a record of all changes made to the system, including the date, time, description, reason, authorization, and impact of each change3. A change control log can help the IS auditor to verify whether modifications to the operating system parameters were authorized by comparing the log entries with the actual system settings and the change approval documents4.