Apple Mac OS X Server is a Unix server operating system from Apple Inc. The server edition of Mac OS X is architecturally identical to its desktop counterpart, except that it includes work group management and administration software tools. These tools provide simplified access to key network services, including a mail transfer agent, a Samba server, an LDAPserver, a domain name server, and others. Also included (particularly in later versions) are numerous additional services and the tools to manage them, such as web server, wiki server, chat server, calendar server, and many others.
Mac OS X Server is the operating system of Xserve computers, rack mounted server computers designed by Apple. Also, it is optionally preinstalled on the Mac mini and Mac Pro ideal for smaller businesses.