As an introduction for new CICS® users, this section presents deliberately simplified definitions of the CICS intercommunication functions.
A program in system CICSA accesses resources (such as files or transient data queues) that are owned by remote system CICSB as though they were locally owned. The diagram shows a data-access request.
Asynchronous processing is an example of function shipping that does not access data - the shipped request is an EXEC CICS START command for a remote transaction.
A terminal attached to system CICSA runs a transaction in remote system CICSB as though it were a local transaction.
A program in system CICSA links a program in remote system CICSB as though it were running in the local system.
Two programs, one in system CICSA and one in system CICSB, communicate synchronously with each other. This dialog is called a conversation.