The Ceres Workstation was a workstation computer built by Niklaus Wirth's group at ETH Zurich in 1987. The central processing unit (CPU) is a National Semiconductor NS32000, and the operating system, named Oberon System is written fully in the object-oriented programming language Oberon. It is an early example of an operating system using basic object-oriented principles and garbage collection on the system level and a document centered approach for the user interface (UI), as envisaged later with OpenDoc. Ceres was a follow-up project to the Lilith workstation, based on AMD bit slicing technology and the programming language Modula-2.