MTS components can be located on a different computer than the client. A client can call a remote MTS component using a special implementation of COM called Distributed COM (DCOM), HTTP, or Remote Automation. To run an MTS component on the client computer, MTS must be installed.
Figure 3.7 Communicating with an MTS component
DCOM is the standard transport for calling MTS components. To enable DCOM calls to MTS components, you must configure the following:
The easiest way to configure your client application to call a remote MTS component is to use the Client Install Utility, which automatically configures client registry settings.
You may have to configure the impersonation level and authentication level on both the client and server computers. MTS uses the default values for these settings: Identify for impersonation level and Connect for authentication level. Changing the default settings by using the DCOM configuration utility (DCOMCNFG) is not recommended. Necessary changes should be made at the package level in the MTS Explorer.
If you want to use Microsoft Windows 95-based clients with MTS, install DCOM for Windows 95.
NoteDCOM version 1.1 for Windows 95 is available for download from the Microsoft Web site. For the latest information on DCOM support for Windows 95, see http://www.microsoft.com/oledev.
Remote Automation was introduced with Visual Basic version 4.0, before the introduction of DCOM. Remote Automation is useful for 16-bit clients, because DCOM only works with 32-bit clients. To use Remote Automation with MTS, the Remote Automation Manager (RACMAN) must be running on the server where the MTS components are installed. For more information, see the Visual Basic documentation.
NoteMTS security cannot be used with Remote Automation because all calls are made using the RACMAN identity. Because RACMAN does not impersonate when calling components on the server, the client identity cannot be determined.
You can use Transaction Server to deploy scalable server applications built from ActiveX components. Components are in-process servers or DLLs. You can create and implement these components with Visual Basic, Visual C++, Visual J++, or any ActiveX-compatible development tool.
MTS simplifies the development of components by allowing you to perform work with transactions. This protects applications from anomalies caused by concurrent updates or system failures.
The standard transport for calling MTS components is a special implementation of COM called DCOM. To enable DCOM to call components, you must configure the client registry settings and the DCOM security settings.