"In any proceedings, a statement in a document produced by a computer shall not be admissible as evidence of any fact stated therein unless it is shown. That at all material times the computer was operating properly, or if not, that any respect in which it was not operating properly or was out of operation was not such as to affect the production of the document or the accuracy of its contents."
they have now changed the position to
"in the absence of evidence to the contrary, the courts will presume that mechanical instruments were in order at the material time... The principle has been applied to such devices as speedometers and traffic lights and in the consultation paper we saw no reason why it should not apply to computers."
I have no earthly idea, where the assumption about not checking calculations, or "don’t need to show why it produced the results it did." comes from or how you arrived at that conclusion.
your logical seems as daft as asking if I've ever used a computer system, on a computer system.
The general assumption in dealing with computer systems should always be to assume that they contain bugs. There have been detailed studies in the defence and medical industries into flaws in critical computer systems, and bugs are endemic in complex computer systems. We should always be prepared to question the results we get, check, test and double check.
In critical cases where there is a question about the validity of the results, they must be checked. In these cases they were not checked, they were assumed to be correct because the subpost-masters and mistresses in the case could not provide evidence that the software was wrong. But then, how on earth could they?
Questioning the validity of results and working hard to validate test and audit results is an approach that is well supported by the evidence and has served me well in my professional career.
> check, test and double check.
Clearly that's not what you want to do, because you want to assume the computer is wrong without evidence as you stated. Testing might provide some evidence.
> could not provide evidence that the software was wrong. But then, how on earth could they?
Well, I suppose they could "check, test and double check." Or is that unreasonable?
Their position was that you don’t need to check the calculations, don’t need to show why it produced the results it did, you just assume it’s always correct. I work in the finance industry myself and have supported financial applications in banks and exchanges and the way these cases were handled is unbelievable. We’d never make assumptions about our systems like this, it was grossly negligent and incompetent and the courts need very clear guidance on how to do better.