Failed intercept at Dhahran caused by a software error in handling of timestamps

The inimitable comp.risks discussed this in 1992:

http://catless.ncl.ac.uk/Risks/13/35#subj1.1

http://catless.ncl.ac.uk/Risks/13/76#subj8.1

And in 1997:

http://catless.ncl.ac.uk/Risks/18/79#subj9.1

Fair. I wasn't replying to you, your #1 sounds a lot like what I'm saying, though.

  1. I remember hearing the system was only designed for
  XX operational hours but was being run over the
  operational spec.

This is very similar to my "at least" which is very different than "at most". In requirements we wouldn't bound ourselves like that. We wouldn't say our system should run for at most 8 hours. We'd say it should run for at least 8 hours. However, we won't say what happens after 8 hours because we don't test it (it's not a requirement). We may communicate to the operators that the system should be rebooted after some period of time if there's a known or anticipated issue, or we may include a soft boot to reset things. For many of our systems, their operating time is usually under 12 hours (they go on aircraft that don't fly for days at a time, mostly), so we never test anything past about 48 hours anyways. If there's an issue that arises around 96 hours, we'd never know from our testing and only know about if an operator pushed it to that limit and recorded the circumstances properly.

This was a tragic and preventable loss. It's incredible that a software bug might have been the root cause.

At the time, this incident really stuck out because it broke the illusion of our fabled Patriot missile shield protecting us. Civilian expats really believed the inflated Patriot interception rates parroted to us by mainstream media and our American military expat buddies.

A large number of remaining expats who had stuck out the Gulf War to that point decided to pack it in and leave when word got out that the Dhahran barracks were hit. Although history shows that Iraq surrendered days after this incident, at the time there was heightened fear and confusion amongst the remaining expats, especially the non-Americans.

We left on the last Lufthansa flight (crewed by military personnel) after hearing about this.

Nostalgic edit:

During the Gulf War embassies issued equipment and rations to expat citizens who chose to stay behind. Americans were issued full body suits (for adults and youths) due to the biological and chemical weapon payloads that Saddam boasted his SCUDs were carrying, along with MREs that tasted fabulous! In stark contrast, Commonwealth citizens were issued a bare gas mask (adult size only) and mono-flavour MREs that tasted like cardboard.

The British embassy sticks out in my mind: with stern stone-faced expressions they admonished us all for not evacuating and thus endangering children in a war zone. In addition to the terrible rations and gas masks, they wordlessly gave us a stack of translucent stickers. When asked what they were for, embassy staff explained that in the event of the air siren going off, we should get under our sturdiest tables and don our gas masks (standard procedure), and then slap the stickers on. If the stickers changed colour, it meant we were in the presence of a biochemical agent and would have approximately 10 seconds before we died a horrific death.

You kind of had to be there to appreciate the grim humour.

I could be reading this wrong, but 1/3 of a second within 100 hours seems really good, like something you'd get from a temperature-controlled crystal oven.

I don't mean to second-guess them in an area I know so little about, but if that was enough to cause a serious issue in the span of only a few days, shouldn't the devices be designed with a separate synchronization system, at least as a backup? Maybe GPS?

Which brings up a sort of interesting question...would a Patriot missile system even have receivers for a weak public signal like GPS, or is it all self-contained?