Post #4152891

@mattblaze@federate.social A classic case. See https://www.newscientist.com/article/1818118-technology-sorry-no-numbers-the-day-the-uss-telephone-network-crashed/ and https://catless.ncl.ac.uk/Risks/9.63.html#subj3.1 — and https://catless.ncl.ac.uk/Risks/9.69#subj5 for the precise bug: misuse of a a 'break' statement. The salient points: it was a flaw in error recovery code, which was triggered if and only if while a phone switch was rebooting, it received two incoming call requests within 1/100 second. In the aftermath, AT&T started classes in the proper use of 'break' statements…