The NeXTStep operating system was designed by a team led by Avie Tevanian, who was a member of the team that designed the Mach Microkernel at the Carnegie Mellon University alongside the BSD personality for it. NeXTStep is basically a version of the Mach kernel and a BSD personality with a layer of object-oriented user interface on top, that is implemented in Objective C.
- 1989: NeXTStep 1.0
- 1990: NeXTStep 2.0
- 1991: NeXTStep 2.1
- 1992: NeXTStep 3.0 - 4.3BSD-Reno
- 1993: NeXTSTEP 3.1 - support for Intel 486, HP PA-RISC, SPARC
- 1993: NeXTSTEP 3.2
- 1995: NeXTSTEP 3.3