From a Software Developer perspective, it was quite frustrating that Post Office would try to minimise the number of Software Bugs in the Horizon System (whatever that is). Often it felt that people simply did not understand the Software Development Process and made statements based upon their limited understanding. The Inquiry usually never challenged these statements and so they stand uncorrected on the record. To be honest the Inquiry remembered all these statements and then used them to impeach that witness.
Ms Paula Vennels was caught in an attempt to downplay a bug by calling it something else. Although this was largely pointless it did provide good entertainment value to some of the audience! In fact the development community sometimes do the same thing! Bugs are assigned a Priority and no release is possible until the number of priority one bugs are below a certain level. Some project managers have been know to manipulate the number of problem priorities. None of that development priority information was ever disclosed to the Inquiry, in fact no development information was disclosed to the Inquiry. I will return to this point.
The ITV show “Mr Bates vs the Post Office” had a section on Lee Castleton’s case. The Post Office witness is portrayed as saying only about 60 Post Offices had that bug. It is difficult to comprehend what they meant by that. I’m not sure how correct that is but I did have a brief discussion with a Post Office employee who made much the same statement. It is difficult to assign any meaning to that statement.
One example might be Microsoft’s “Patch Tuesday” each month (or more often if necessary). They release all chosen fixes in one go. Although all those bugs were reported by one person nobody attempts individual fixes. This is because bugs are fixed in the Code, who reported it is utterly irrelevant. Fixes are entered into a release and it is distributed to everybody.
The same is true for Horizon, fixes are made and released to everybody. At least they should be. The idea that only some people have bugs is utter nonsense. Perhaps some problems depend on site specific hardware. The Inquiry and Courts should never have accepted this point without detailed explanation (by a competent developer)