The UNIX server allows multiple users to log on simultaneously and have access to files on the server. Windows NT also allows multiple users to log on using the Remote Desktop Connection.
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.