Avie Tevanian

Avadis "Avie" Tevanian, Jr. is an American software engineer and former senior vice president of software engineering at Apple from 1997 to 2003, before serving as chief software technology officer from 2003 to 2006. There, he redesigned NeXTSTEP to become macOS. Apple's macOS and iOS both incorporate the Mach Kernel, and iPadOS, watchOS, and tvOS are all derived from iOS. He was a longtime friend of Steve Jobs. At Carnegie Mellon University, he was a principal designer and engineer of the Mach operating system. He used that work at NeXT Inc. as the foundation of the NeXTSTEP operating system.