Back in 2009, I did a short BizTalk project that used Host Initiated Processing (aka “HIP”).  This is one of the five features of Host Integration Server (HIS).  Starting with the BizTalk 2009 release, HIS is no longer sold separately, and can only be obtained along with a BizTalk license.

1. HIP – Host Initiated Processing – CICS transactions send a request to BizTalk for a response, example, a CICS program calls a COBOL subroutine, which in turns talks to BizTalk, which could run an orchestration and call an external web service.
2. WIP – Windows Initiated Processing – Windows sends a request to CICS and waits for a response.
3. DB2 – Ability to read/update DB2 database tables.
4. Host Files – Ability to read/write VSAM files
5. TI – Transaction Integration – Remote control of CICS screens.