Charlie, I don't like your analogy that integrated control & safety is like combining emergency brakes with conventional brakes. That analogy implies 100% common cause between the 2 systems and thus a single layer of protection. That is NOT what integrated control & safety means to most people. The major suppliers of integrated control & safety systems (e.g. Honeywell, Siemens, ABB, Emerson & Yokogawa) all provide solutions that use dedicated controllers and I/O for the safety system. Some offer an integrated engineering environment and some offer integrated communications but they are all certified by TUV such that the non-safety components are non-interferring, that is a failure of the non-safety components will not interfere with the ability of the safety system to perform it's safety function. Properly implemented, in these integrated architectures the DCS and the Safety system can be treated as independent layers of protection. A better analogy is this. Imagine if, in the past, auto manufacturers didn't provide emergency brake systems. So, if you wanted one you had to take your car to a special niche supplier to have an aftermarket emergency brake system installed. They worked fine but they were costly and complex to install and didn't integrate well into the car. Maintenance was was costly because you had to go to separate garages for parts and service. Over time, the automakers decided to offer an emergency brake system as an option in their vehicles. These systems operated just like the aftermarket systems and complied with the same rigorous design and testing. Customers could now have the advantage of getting the auto with the emergency brake system installed and nicely integrated into the car. They could also go the same garage for service on both. The "compromise" is that while the brake systems are independent they were designed, manufactured and installed by the same supplier. They may even have some common parts. This is an insignificant compromise when compared to the benefits. Especially if an independent 3rd party safety agencies have evaluated the risks and certified the design to be safe. I argue that this scenario is perfectly analagous to what is occurring today. The major automation suppliers, like the major automakers, have all introduced an integrated safety systems when in the past you had to go to a different, specialty supplier. How would you expect the niche suppliers of the aftermarket emergency brake systems to respond? Of course, they're going to aggressively defend their market! How? By trying to scare consumers by saying they are putting their loved ones at risk by trusting an emergency brake system installed by the same manufacturer as the conventional brake system. This is exactly what is happening today with programmable safety systems. The niche, specialty suppliers are aggressively defending their market. Who could blame them? But, then again, who would continue buying an aftermarket emergency brake system when they could get one with their car?