Access to Legacy Applications and Data

Functional Overview of the COM Transaction Integrator

The following list summarizes how COMTI gains access to CICS applications. It also shows how COMTI integrates data returned from CICS transaction processing programs with IIS 5.0, by using COM components and Component Services. Specifically, COMTI can:

Gain Access to CICS Transaction Processing Programs COMTI directly supports any transaction processing program that executes in CICS or IMS. Because COMTI can access CICS programs, developers can issue application calls to the legacy environment, by using CICS to gain access to any program under its control. This includes DB2 databases, VSAM files, or IMS databases.
Redirect Method Calls COMTI is a generic proxy for the mainframe. It intercepts method calls from the client application and redirects them to transaction processing programs running on the mainframe. For example, when an Internet browser sends data that ASP interprets as requiring COMTI, IIS forwards the data to COMTI.
Reformat Method Calls When COMTI intercepts a method call, it converts and formats the method’s parameters from Automation data types into IBM System 390 mainframe data types.
Handle Return Values COMTI handles the return of all output parameters and values from the mainframe, converting and reformatting them for IIS as needed.

COMTI processing runs on computers using Windows 2000 Server, not on the SNA host. It does not require any new executable code to be installed on the mainframe, or on the desktop computer that is running the Internet browser. COMTI communicates through SNA Server 4.0 SP2. It uses standard protocols (LU 6.2 or TCP/IP, each of which is supported on SNA Server 4.0 SP2) in order to communicate between the computer running Windows 2000 Server and the mainframe transaction processing program.