Comment by fao_
12 hours ago
> Poor quality code might have caused the error, but the failure to investigate the errors and sweep them under the rug was made by humans.
That's not quite correct.
The root set of errors were made by the accounting software. The branch sets of errors were made by humans taking Horizon IT's word for it that there was no fault in the code, and instead blaming the workers for the differences in the balance sheets.
If there were no errors in the accounting software (i.e. it had been properly designed and tested), then none of that would have happened.
Nobody blames THERAC-25 on the human operator.
It was worse than that. Higher ups in the post office knew the system was buggy and still doubled down on it. Yes, if the accounting software wasn't terrible the whole issue would not have happened, but there were so, so, many chances for the post office to do the right thing afterwards that it's not at all fair to blame the results on the poor quality software, which very notably did not prosecute thousands of people for fraud while telling each of them they were the only ones being flagged by the system.
(THERAC-25 was a little more towards 'just bad software', but there were still systemic failures there as well).