What Are Examples of Multi-User Operating Systems?

The UNIX system uses fewer resources than the Windows system. While there is a high initial resource output with UNIX, the system uses few resources for each additional user. For example, users share memory to run certain aspects of applications. By contrast, a Windows system starts a new session each time a user logs in. This requires a much higher resource output for each user, but is more secure because users do not share resources across sessions.