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List:       bugtraq
Subject:    Re: Did a 16-bit counter overflow shut down Comair?
From:       Avleen Vig <lists-bugtraq () silverwraith ! com>
Date:       2004-12-29 8:41:12
Message-ID: 20041229084112.GK21044 () silverwraith ! com
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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
> 
> 

-- 
Avleen Vig
Systems Administrator
Personal: www.silverwraith.com
EFnet:    irc.mindspring.com (Earthlink user access only)
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