Richard Smith offers up some background, and links on the Comair shutdown this past weekend.
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 wise choice.
It’s generally amazing things work as well as they do This example also demonstrates the importance of keeping software up to date….