>Perhaps I should have said that the MTBF must be based on certain >observational data but must be essentially a prediction as a real-time >testing process isn't possible. > >How are these values derived?
1) By maths based on component MTBFs. (supported by tests of the components), and 2) sometimes supported by testing of large numbers of the final item, or 3) by accelerated testing and more arguable maths. Julian Julian Canberra, Australia http://members.austarmetro.com.au/~julian/photo-an/photo-an.htm ---------------------------------------------------------------------------------------- Unsubscribe by mail to [EMAIL PROTECTED], with 'unsubscribe filmscanners' or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or body