What is CICS Transaction Server for z/OS?

CICS® Transaction Server, often called simply CICS, is a powerful, mixed-language application server that runs on the IBM® mainframe operating system called z/OS®.

An application server provides an environment to host applications. It can provide services to solve many concerns, such as security, transactionality, or exchanging data between new and existing applications. Developing custom enterprise-grade solutions for these issues is difficult and can take time away from focusing on what the application is intended to do for the business. Importantly, CICS can provide these services to applications that are composed of components written in different programming languages.

CICS is used as an application server by a host of different companies in numerous industries, such as banking, transportation, retail, and insurance. The kind of applications that run in CICS often form the core of the owning business and are critical to their success. If these applications fail, unexpected downtime or errors can result in significant revenue loss and impact on reputation. This significance means that they need to run on a highly available, reliable, and robust platform such as CICS.

Prefer video?

A series of short videos, hosted on the IBM Redbooks® site, explores what an application server is, what it provides to application developers, and what distinguishes CICS as a mixed-language application server: Introduction to CICS - an IBM Redbooks course.