One of Apple's top Mac OS X engineers, Wilfredo Sanchez, has left Apple to join a Web start-up company.

Sanchez joined Apple in July 1997 as senior software engineer, before becoming a scientist at Apple's Core Operating Systems Group. His last post, as head of Open Source Engineering, saw him leading the team responsible for OS X's open source BSD (Berkeley Software Distribution) Unix core – better known as Darwin.

Sanchez was responsible for allowing OS X's APIs (Application Programming Interfaces), graphics sub-systems and Aqua GUI (Graphical User Interface) to operate on top of the Unix-driven BSD core.

His work led to the release last April of the Darwin source code, and the launch of Apple's Public Source version of the open-source licence.

Sanchez has taken up a position as open source program manager with California-based target="_blank">KnowNow, a start-up that describes itself as "powering the two-way Web".

The Register reports that Sanchez plans to maintain the OS X versions of the Perl programming language and the Apache Web server – which he can do thanks to its open source nature.

Mac OS X will ship on Saturday, 24 March.