Re: Did a 16-bit counter overflow shut down Comair?
This isn't at all surprising.
There are numerous industries which run "old" software like this. There
are several reasons not to upgrade:
1) The software is currently "good enough"
2) It would cost too much to upgrade
3) The original designers are long long gone and no-one knows
everything about the application any more (although this is
also a
reason TO upgrade).
There are several money-lending organizations which run "old" software
like this too quite happily.
On Tue, Dec 28, 2004 at 12:44:20PM -0500, Richard M. Smith wrote:
> Hi,
>
> On Christmas Day last Saturday, Comair Airlines had to completely stop
> flying
> all of its planes due to computer problems. Comair blamed the computer
> problems on their pilot scheduling software being overloaded after bad
> weather earlier in the week forced many flights to be rescheduled. Comair
> now hopes to have all of its 1,100 daily flights restored by tomorrow.
>
> An article which was published today at the Cincinnati Post Web site
> provides some interesting details of a software failure in Comair's pilot
> scheduling software:
>
> How it happened
> http://www.cincypost.com/2004/12/28/comp12-28-2004.html
>
> According to the article, Comair is running a 15-year old scheduling
> software package from SBS International (www.sbsint.com). The software has
> a hard limit of 32,000 schedule changes per month. With all of the bad
> weather last week, Comair apparently hit this limit and then was unable to
> assign pilots to planes.
>
> It sounds like 16-bit integers are being used in the SBS International
> scheduling software to identify transactions. Given that the software is 15
> years old, this design decision perhaps was made to save on memory usage.
> In retrospect, 16-bit integers were probably not a good choice.
>
> An anonymous message posted to Slashdot the day after Christmas first
> described the software failure at Comair:
>
> http://slashdot.org/comments.pl?sid=134005&cid=11185556
>
> Earlier this year, an overflow of a 32-bit counter in Windows shut down air
> traffic control over southern California for 3 hours:
>
> Microsoft server crash nearly causes 800-plane pile-up
> http://www.techworld.com/opsys/news/index.cfm?NewsID=2275
>
> This problem occurred because of a known design flaw in older versions of
> Windows:
>
> http://tinyurl.com/5n9gc
>
> Richard M. Smith
> http://www.ComputerBytesMan.com
>
>
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Avleen Vig
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