<Moderator's note: this subthread has been given a new topic and
title.>

> From: Peter Whalley <[email protected]>
> Subject: Re: ALL: An (open) announcement

> My understanding is that SOAP enables applications to
> intercommunicate via
> the Web using http and XML. Whilst it may replace DCOM in
> this application
> it would not neccessarily replace OPC.

This is obviously true. The main issue is likely to be performance, both at each end and in terms of network load. Most of the complexity of OPC is caused by it going to a lot of work to define a complex structure that can hold a lot of binary data to amortize network overhead. A similar XML structure will both be much larger and require substantially more CPU resources to construct and parse.

Despite the above, I expect the corporate world to
move to XML based data transport whenever possible. This makes the adoption of SOAP both reasonable and likely. However, I question how much payback there'll be from an OPC-like mass of data wrapped in SOAP/XML versus simpler structures.

Dan Pierson, <[email protected]>

 

At 15:34 29.03.00 -0500, you wrote:
>From: Peter Whalley <[email protected]>
>
>I think we need to be clear about what SOAP replaces and what it enables.
>
>My understanding is that SOAP enables applications to intercommunicate via
>the Web using http and XML. Whilst it may replace DCOM in this application
>it would not neccessarily replace OPC. Thus applications couldn use OPC to
>exchange controller data and if they went via the Web then the OPC data
>would be carried using SOAP. Taking this further, a CORBA based application
>might talk to an OPC application across the Web using SOAP.

CORBA doesn't need SOAP ... the IIOP protocol can be used across the Web. That means CORBA integrates the functionality of Web communication and object oriented data communication seamlessly.

Regards

Armin Steinhoff

 

Yes until CORBA reaches the Firewall!!!! Bang a gotcha.

 

Armin -

CORBA doesn't need SOAP to talk to OPC - it's OPC that needs SOAP so as to be accessible from CORBA.

-- Paul McGuire
KLA-Tencor Control Solutions
(formerly ObjectSpace Fab Solutions)
Austin, TX
- Advanced Process Control Solutions for the Semiconductor Industry -