Host Application Integration Using COMTI

As SNA networks are integrated with client/server-based networks, many organizations are investigating ways to leverage the power of host systems to run new client/server applications accessible from the personal computer. One method is by using SNA Server's COM Transaction Integrator (COMTI) feature for IBM's Customer Information Control System (CICS) and IBM's Information Management System (IMS).

COMTI simplifies the process of creating applications that consist of Automation clients running on the desktop or server with COBOL servers running under CICS or IMS. Any application or development platforms that support Distributed COM (DCOM) and Automation can use COMTI components. For example, an application written in VB, VBA, or VBScript, can provide access to host data from within Excel. This feature can also be used through Web browsers that connect to Microsoft® Internet Information Services (IIS).

COMTI provides an interface between Automation components and mainframe-based applications. Running on Windows 2000 Server, components appear as simple Automation servers that developers can easily add to their application. Behind the scenes, however, COMTI functions as a proxy that communicates with an application running on IBM's Multiple Virtual Storage (MVS) operating system.

Applications that run in part on Windows platforms and in part on the mainframe are distributed applications. COMTI supports all distributed applications that adhere to Automation and DCOM specifications, although not all parts of the application have to adhere to these standards.

COMTI is composed of three parts:

• The Component Builder, which is used to create Automation components.

• Microsoft Management Console (MMC), which is used to manage components created with the Component Builder.

• The COM Transaction Integrator Runtime, which provides the Automation server interface for each component created with the Component Builder and which communicates with the mainframe programs. The run time operates within Component Services.

COMTI directly supports any transaction program (TP) that executes in CICS and is structured to use either distributed program linking or Advanced Program-to-Program Communications (APPC) verbs. It also directly supports IMS applications that are structured to use the IMS Message Queue. Because COMTI can access CICS programs, developers can extend the client application calls even further by using CICS to access any other program on an MVS mainframe, such as DB2.

Figure 10.30 shows how SNA Server can be integrated with a host application. A client application uses the COMTI feature hosted by Component Services to access a TP running on the mainframe. The specific TPs supported by the feature are IBM's CICS and IBM's IMS. An example of this type of distributed application is one that reads a mainframe-based DB2 database to update data in a SQL Server database on a Windows 2000–based server.

Figure 10.30 Integration with a Host Application

The client components can run on any platform that supports DCOM, including:

• Microsoft® Windows NT® Server

• Microsoft® Windows NT® Workstation

• Windows 95 and Windows 98

Because DCOM is language-independent, developers can build their client applications using the languages and tools with which they are most familiar. Common client/server application development environments include:

• Visual Basic (VB)

• Visual Basic for Applications (VBA)

• Visual C++ (VC++)

• Visual J++ (VJ++)

• Borland Delphi

• Sybase Powerbuilder

• Microfocus Object COBOL

Once created, the client components can make calls to the COMTI Automation object (or any other Automation object) registered on the computer running Windows 2000 Server.

Complete information about using COMTI, including sample applications, can be found in SNA Server COM Transaction Integrator Help.