>>You may have individually proven every algorithm, but interaction between algorithms and the event driven OS introduces more possibilities than can be reasonably proven.
>
>Well said, and precisely my point. An example I use in my testing presentation (and CoDe article, IIRC) was created by Genford Myers (well respected testing author). The program had a few pieces of branching code, a loop, and that’s about it. Could be written in most languages in about 20 lines of code. Myers calculated that it had 100 trillion different code paths. A fast tester could test that in about a billion years. :-)

Mike;

Could that be one of the reasons that Apple Computer SQA department uses a Cray Computer at the Cupertino Headquarters Office for software testing before it approves software for release? :)

Tom