anthony@uunet.uu.net> (02/10/90)
In the offical explanation of the AT&T outage, the following was written about the software flaw. >with the main CCS7 signaling network. While the software had been >rigorously tested in laboratory environments before it was introduced, >the unique combination of events that led to this problem couldn't be >predicted. I would really like to know if AT&T does rigorously test their software as they claim. Can anyone confirm that ? Furthermore does a company like AT&T use any of the modern software engineering techniques for their software development ? e.g. Formal Specifications, Proofs of correctness of critical parts of software etc.? The point is that the FAA required that proofs of correctness of flight control software be provided so why aren't there similar requirements for critical software within the 4ESS ? If the financial communities in the US are so dependent on the AT&T network then shouldn't they have satisfaction of knowing that they can relied on the fact that the software in the 4ESS to work correctly? That is, if a passenger on a modern jetliner places his life in the hands of an engineer who wrote the flight control software of the jetliner and that engineer has to prove his software is correct then what permits an engineer at AT&T to write some code for the 4ESS without proving the correctness of that code ? I don't know if they do program correctness proofs at AT&T but if they do, then my apologies. Anthony Lee (Humble PhD student) (Alias Time Lord Doctor) ACSnet: anthony@batserver.cs.uq.oz TEL:+(61)-7-371-2651 Internet: anthony@batserver.cs.uq.oz.au +(61)-7-377-4139 (w) SNAIL: Dept Comp. Science, University of Qld, St Lucia, Qld 4067, Australia