This document summarizes different network operating systems (NOS) including Microsoft Windows Server, Novell NetWare, UNIX/Linux, and Apple Mac. It describes key features of each like how Windows Server uses domains and trusts, how Novell NetWare uses its file system and directory services, how UNIX/Linux uses TCP/IP and X Windows, and how Apple Mac used AppleTalk and file/printer sharing between clients. The document also provides overviews of common server utilities, client applications, and networking models associated with each NOS.