The Active Directory Domain Services (AD DS) role installs Active Directory and turns a Windows Server 2008 computer into a domain controller. AD is a database of objects in computer it is used for authentication for users and computers. Active Directory is the foundation of a Windows network environment. This directory service enables administrators to create and manage users and groups, set network-wide user and computer policies, manage security, and organize network resources. Provides a single point of administration of network resources, such as users, groups, shared printers, shared files, servers, and workstations. Provides centralized authentication and authorization of users to network resources. Along with DNS, provides domain-naming services and management for a Windows domain. Enables administrators to assign system policies, deploy software to client computers, and assign permissions and rights to users of network resources.
RODC is read only domain controller used in remote locations such as branch office
Terminal server allows remote desktop applications.
Groups- Backup Operators, Administrators and Domain Administrators, remote desktop users, Domain users Print Operators, Server Operators, IIs users, Network Configuration Operators
Hyper-V feature that comes with Standard, Enterprise, and Datacenter editions.
Server versions- Standard Edition supports up to four processors. Standard Edition is available in 32-bit and 64-bit versions. The 32-bit version supports up to 4 GB RAM, and the 64-bit version supports up to 32 GB RAM. Clustering and support for more processors, are reserved for higher-end editions. Users of the 64-bit Standard Edition can install one virtual instance of Server 2008 Standard Edition with Hyper-V.
Enterprise, Enterprise Edition supports up to eight processors and 64 GB RAM in the 32-bit version and up to 2 TB of RAM in the 64-bit version. Server clustering is the most notable feature in Enterprise