NBC News reports here on a pair of computer problems that have caused flight delays. In the past few months, both Delta and Southwest suffered computer problems that severely disrupted their flight operations.<p>
These problems were all related to information technology (IT)---traditional issues related to databases, networks, etc. Nonetheless, they disrupted the physical plants of the airlines in the form of flight delays. We often treat CPS and IT as separate domains but in the real world they blend together.<p>
Many utilities separate their billing and management IT systems from their computer systems that operate equipment. Nonetheless, these systems must talk---you can't bill unless you know something about the equipment's operation. And the operational computer systems that perform cyber-physical operations such as control make extensive use of hardware and software originally designed for IT.
A chain is only as strong as its weakest link. If we want to build safe and secure cyber-physical systems, we need to be sure that IT and CPS work together.