Mainframe Glossary

Common Business-Oriented Language. A programming language developed in 1959, still running in 95% of ATM transactions and 80% of in-person transactions.

Customer Information Control System. IBM transaction processing middleware that handles millions of transactions per second in enterprise environments.

IBM's relational database management system, commonly used on mainframes for enterprise data storage and OLTP workloads.

IBM's 64-bit operating system for mainframes, providing high reliability, security, and continuous availability for enterprise computing.

Million Instructions Per Second. The primary unit for measuring and licensing mainframe computing capacity.

Job Control Language. Scripting language used to instruct z/OS how to run batch jobs and allocate resources.

Virtual Storage Access Method. IBM file access method used for organizing, storing, and retrieving data on mainframes.

Information Management System. IBM hierarchical database and transaction manager, one of the oldest DBMS still in production use.