Can I use OPC or DDE on Windows Vista?

The Dynamic Data Exchange (DDE) protocol is a set of messages that uses shared memory to exchange data between applications.  DDE has been available since Windows version 3.1 and still has support in Windows XP and Vista. Network Dynamic Data Exchange (NetDDE) is an extension of the DDE protocol that has existed since the very early versions of Windows.  Much like using a remote printer or directory, a NetDDE Share must be configured before the applications can exchange data.  Although it is available on Windows XP and 2003 Server, it is disabled by default.  NetDDE is NOT available on Windows Vista.

 

OPC is based on the COM/DCOM.  COM is a binary standard that enables objects to interoperate in a networked environment and includes ActiveX Controls, Automation, and object linking and embedding (OLE) technologies.  DCOM builds upon the remote procedure call (RPC) technology, and was designed to give developers more control over security, as compared to other interprocess communication mechanisms.

 

While DDE is considered simpler to use, due to improved robustness and security, OPC is considered to be the better choice for industrial applications.  When comparing the two protocols, users should consider: Supportability, Interoperability, Speed and Through-put, Scalability, Robustness and Security.  A full discussion on this topic can be found here.