Don't go that high, Airbus do the same from the navigation to the airplane control system everything which is critical for flying the plane. As far as I know even the hardware is designed by a 'shadow team'. Tamas On 4/10/07, Herbert Graf wrote: > > On Tue, 2007-04-10 at 13:38 -0400, William Couture wrote: > > Just as a datapoint: > > > > The Space Shuttle uses redundant computers. > > > > And part of the redundancy is that some of them run software > > that is written by a different company from the same specs. > > Hehe, was just about to post something very similar. > > I believe such a thing was common in the Apollo days as well, aside from > redundant different hardware, the software was also independently > developed to ensure one software bug wouldn't take out everything. > > TTYL > > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > -- unPIC -- The PIC Disassembler http://unpic.sourceforge.net -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist