Peter, I think that you are forgetting one very important aspect of creating software reliability; EXPERIENCE. Looking back I know of unreliable coding I did early on as well as unreliable coding I had to find in software produced by "kids" (my affectionate name to those with less than 5 years exp.). Some of the more obscure (to the non-afficionado) features of the various uCs can cause you to lose your hair till you have gained the experience. I have done embedded since the PDP-8 was THE embedded processor and am still learning.