I recently tweeted an article from Ars Technica on Linux technology being used by Raytheon for US Navy warships.
The Navy’s newest warship is powered by Linux http://t.co/AsUhQV125P
— Zydeco Digital LLC (@ZydecoDigital) October 24, 2013
Although the article is recent the technology is old. I worked on projects 10 years ago that utilized the same concepts – military grade server hardware that is not susceptible to vibrations or EM, Ethernet based network that connects various components to various control points, a push / pull data subscription model based on widespread industry protocols (ARINC), and SBC embedded devices that interface to various equipment such as water systems, entertainment systems, lighting, etc.