Windows Server is a brand name for a group of server operating systems released by Microsoft. It includes all Windows operating systems branded "Windows Server", but not any other Microsoft product. The first Windows server edition to be released under that brand was Windows Server 2003. However, the first server edition of Windows was Windows NT 3.1 Advanced Server, followed by Windows NT 3.5 Server, Windows NT 4.0 Server, and Windows 2000 Server; the latter was the first server edition to include Active Directory, DNS Server, DHCP Server, Group Policy, as well as many other popular features used today.
This brand includes the following operating systems:
Certain editions of Windows Server have a customized name. For example, all editions of Windows Server to this date had a Windows Storage Server edition. Other examples include Windows Home Server and Windows HPC Server.
Microsoft has also produced Windows Server Essentials (formerly Windows Small Business Server) and the discontinued Windows Essential Business Server, software bundles which include a somewhat restricted Windows Server operating system and some other Microsoft Server products.
Users of Windows Server may choose to deploy either on-site or using a cloud computing service. Each provides different advantages.
By delegating the managing and upkeep of the server to a cloud computing service such as Microsoft Azure or Amazon Web Services, users get the benefit of paying monthly based on usage rather than a large fixed cost. Furthermore, infrastructure tends to be more reliable and it is easier to scale up as necessary. However, buying and running a server in-house may be a better choice in certain cases when it is more cost effective. Other use cases such as using a Windows server to manage client computers in a facility are also appropriate for running a physical server.