What's a DCS?

Somebody wrote to the A-List at control.com a while back, and claimed that while XYZ and ABC were DCS systems, two other companies' systems, in his not-so-humble opinion, didn't qualify. Last year, in a discussion with Emerson's Chief Strategic Officer, Peter Zornio, we came up with the following definition of a Distributed Control System: "A DCS is a set of proprietary field controllers connected to field devices via analog or digital field level networks and connected to a central control function via open networks such as Ethernet. The Central Control function consists of COTS (commercial off the shelf) computers running a proprietary integrated software suite." That pretty much allows any field controllers with an integrated set of software running them into the definition, don't you think? Last week, in a discussion with Rockwell's Rick Dolezal, the subject came up again. Rick noted that nobody sells DCS systems anymore, and offered this list as evidence: Who sells a DCS? No one, apparently...From each of their web sites: Foxboro (InFusion) - Enterprise Control System Honeywell (Experion) - Process Knowledge System Emerson (Delta-V) - Digital Automation System ABB (800xA) - Extended Automation System Siemens (PCS 7) - Process Control System Yokogawa (CENTUM CS) - Integrated Production Control System NovaTech (D/3) - Process Automation System Rockwell Automation - Integrated Architecture for Process So, if nobody is making DCS systems, what are all those end users buying?