The IMS™ batch message processing program (BMP) can request z/OS UNIX services. However, the following applications cannot request z/OS UNIX services:

• Customer Information Control System/ESA (CICS/ESA): A CICS® transaction cannot access a file in a file system, because the access would put CICS in a wait. Also, other z/OS UNIX functions could not be used and would abnormally end CICS.
• Information Management System/ESA (IMS/ESA®): An IMS application cannot access a file in a file system, because the access would put the IMS application in a wait. Also, other z/OS UNIX functions could not be used and would abnormally end the IMS application.