Windows Server appliance
Microsoft Windows, or simply Windows, is a metafamily of graphical operating systems developed, marketed, and sold by Microsoft. It consists of several families of operating systems, each of which cater to a certain sector of the computing industry with the OS typically associated with IBM PC compatible architecture.
More informations on https://www.microsoft.com/en-us/windows
RAM: 2048 MB
You need KVM enable on your machine or in the GNS3 VM.
Documentation for using the appliance is available on https://technet.microsoft.com/en-us/library/cc498727.aspx