pacplyer,
Your reply to Chris Scott makes me doubt your competence, if not your actual provenance and education....
Where I come from (admittedly some time ago), channel A and channel B software were maybe not actually written by two different companies, but definitely by two different teams, using different compilers, etc. etc.
"I submit that both channels use the same code."
If so, things have changed a long way from "my days", and maybe... "Houston, we have a problem"?
Duplicating a mistaek doesn't make it any less of a mistaek.
Duplex hardware monitoring works fine. The chances of any two op-amps, RAMs, PROMs, transistors, or whatever, failing identically, in the identical location in channel A and B are infinitesimal.
But if both channels run exactly the same crudware... when both of them execute exactly the same faulty instruction at the same time, no kind of monitoring is going to catch it.
I'm not suggesting this is really relevant to BA038. I DO think it's relevant to pacflyer's misinterpretation of software reliabilty.
CJ