CICS transaction

A CICS® transaction is initiated by a single request, usually from a terminal. A CICS transaction is equivalent to a Language Environment process. A Language Environment process consists of one or more enclaves that carry out the needed processing when they are run. When a CICS transaction is initiated, the first Language Environment thread is triggered within the first enclave in the Language Environment process.

For example, the insertion of a bank card into an ATM machine might trigger a Language Environment process (CICS transaction) consisting of one or more enclaves (CICS run units) to read the information on the card. After an ATM machine reads a bank card, the validation of the information on the card might be performed by one enclave, processing the user's personal ID number might be performed by another enclave, processing a user request by another, and dispensing the cash by a final enclave.