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HP OpenVMS Systemsask the wizard |
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The Question is: OpenVMS DCOM question Our company has been using OpenVMS for its flagship SCADA product for nearly 20 years. However, we are increasingly offloading advanced functionality to Windows machines since 3rd party vendor support is far better. In searching for a middleware solution between OpenVMS and Windows we decided to use DCOM for OpenVMS as of June 2001. Our initial results looked quite good with the latest OpenVMS and DCOM version (1.1) available at that time. But as of late, we have experienced numerous problems with DCOM at OpenVMS (see REF note 1.3.1 below). Our staff determined the VMS RPC daemon would fail after a small number of DCOM transactions. So we installed the various patches from your website an d we believe the RPC daemon problem has been solved. However, we are also seeing a problem with CoCreateInstanceEx(), where an "access denied" error occurs after a number of successful DCOM transactions. Our DCOM client was designed to do a CoInitializeEx() into an MTA apartment, followed by a guaranteed C oUninitialize() after the transaction completed. By experimentation, we discovered that moving the calling thread into an MTA apartment and leaving it there appears to solve the "access denied" problem. Although we can accept this workaround, this behav ior does not conform to the COM specification. Any comments are appreciated. Sincerely, John Petz Transdyn Controls, Inc Atlanta, GA 678/473-6456 RE: 1.3.1 Windows 2000 Interoperation Requires Compaq DCE Version 3.0 for OpenVMS As part of our interoperability testing, HP has identified a problem in the authentication layer that prevents authenticated COM requests between an OpenVMS COM client application and a Windows 2000 COM server application. In this case, the system returns an 80070005 (E_ACCESSDENIED) error from a call to CoCreateInstanceEx in the COM client application. The problem does not occur with requests between Windows 2000 COM client applications and OpenVMS COM server applications. The solution to this problem is to install the Compaq DCE Version 3.0 for OpenVMS kit. (COM needs only the RPC run time, but to get the RPC run time you must install the DCE kit.) This problem occurs only on versions of OpenVMS prior to Version 7.3. The DCE for OpenVMS Version 3.0 RPC run time ships with the OpenVMS operating system beginning with OpenVMS Version 7.3. If you are running OpenVMS Version 7.3 or higher, you do not nee d to install the DCE kit. The Answer is : Assuming you have the current ECO kits for OpenVMS, TCP/IP Services and DCE, please contact the support center directly for assistance with this resolution.
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