CICS (Customer Information Control System) is a transaction processing system designed for both online and batch activity. A transaction is basically a set of operations performing a task. Usually, the majority of transactions are relatively simple tasks such as updating the balance of an account. On IBM System z servers, CICS easily supports thousands of transactions per second, making it a mainstay of enterprise computing. CICS applications can be written in numerous programming languages, including COBOL, PL/I, C, C++, IBM Basic Assembly Language, REXX, and Java.