What is the primary function of a differencing disk in a virtual machine?

The primary function of a differencing disk in a virtual machine is to keep the parent disk unaltered. When a differencing disk is created, it acts as a virtual layer that captures all changes made to the virtual machine after the point at which the differencing disk was created. This allows the original parent disk to remain unchanged while enabling users to experiment with various configurations, software installations, or changes without affecting the base image.

By using a differencing disk, administrators can easily revert to the original state of the VM if needed, as the parent disk retains its integrity and does not record the modifications made in the differencing disk. Any data written or altered is captured in the differencing disk, thus protecting the parent disk from any direct changes. This functionality is crucial for testing and development scenarios, providing flexibility and ensuring that the base system remains stable and unspoiled by temporary alterations.