Redundancy in SCADA systems based on DCOM


Thread Starter

Ariel Burbaickij

Hello forum participants,
As it is stated in DCOM specification binding information for an object, placed on remote machine, includes, among other things, also the address of the machine (in whatever supported format). As I see it makes ''hot swapping''-solutions for redundance rather imposible. My question is: How known SCADA systems written for
Windows family of operating systems try to solve this issue, i.e. what approaches are taken to provide redundancy in the presence of the described situation with DCOM?

Yours sincerely
Ariel Burbaickij

Mike McLaughlin

I solved the redundancy issue, by using an external communications computer. The Comm Computer, listened to all requests sent from the on-line system, and the responses that were sent as a result. It then repeated the response to the back-up system, when it's request matched the on-line request. It also controlled which computer was actually connected to the real world, and which on got responses only form it's 'remembered' responses. This kept the back-up system up to date with the on-line system should a switch over be needed!

It wasn't much of a computer, for the communications processor either!

Good Luck -MIKEM