Apollo Computer
In the 1980s Apollo Computer originally used UUIDs in the Network Computing System (NCS) and later in the Open Software Foundation's (OSF) Distributed Computing Environment (DCE). The initial design of DCE UUIDs was based on the NCS UUIDs, whose design was in turn inspired by the (64-bit) unique identifiers defined and used pervasively in Domain/OS, an operating system designed by Apollo Computer. Later, the Microsoft Windows platforms adopted the DCE design as "globally unique identifiers" (GUIDs). RFC 4122 registered a URN namespace for UUIDs and recapitulated the earlier specifications, with the same technical content.