The Ceres Workstation was a computer built by Niklaus Wirth's group around 1985. Ceres was a workstation based on the NS320xx a CPU by National Semiconductor. Ceres was a follow-up project to the Lilith, a machine based on AMD bit-slice technology and the programming language Modula-2. The operating system of Ceres, called "The Oberon System" was completely written in the programming language Oberon. It is an early example of an object oriented operating system utilizing garbage collection on the system level and a document centered approach for the user interface.
On the same hardware Clemens Szyperski implemented as part of his PhD thesis an operating system, called ETHOS, which was taking full advantage of object oriented technologies. According to a posting of Clemens Szyperski on usenet the BlackBox Component Builder, formerly known as Oberon/F, incorporates many of his ideas and principles.