Complex sentence: With the exception of Microsoft Windows, the designs of each of the them were inspired by or directly inherited from the Unix operating system, which was developed at Bell Labs beginning in the late 1960s and spawned the development of numerous free and proprietary operating systems.
Split into simpler sentences: With the exception of Microsoft Windows, the designs of each of the aforementioned OSs were inspired by, or directly inherited from, the Unix operating system. Unix was developed at Bell Labs beginning in the late 1960s and spawned the development of numerous free and proprietary operating systems.