CICS fundamentals

This section introduces you to the components and concepts of CICS.

CICS topology
You can distribute CICS applications and the resources they use between interconnected CICS regions. You can group CICS regions into CICS system groups and CICSplexes, and distribute regions across the z/OS systems in a sysplex.
CICS resources
Before you can run a program in CICS, you must supply CICS with information about system resources, including software resources such as programs and data, and hardware resources such as terminals or communications links. At a minimum, you must define a transaction.
What is a CICS application?
An application is a collection of related programs that together perform a business operation, such as processing a product order, or preparing a company payroll. CICS® applications execute under CICS control, using CICS services and interfaces to access programs and files.
CICS and Java
If you are planning to use Java™ in your enterprise, CICS provides the tools and runtime environment to develop and run Java applications in a Java Virtual Machine (JVM) that is under the control of a CICS region. Java workloads that run in a JVM server are eligible to run on a zEnterprise® Application Assist Processor (zAAP).
Making asynchronous requests
Using the asynchronous API commands provided with CICS is a simple way to issue requests to external services and have them run asynchronously. Instead of calling each service sequentially and waiting for a response, the asynchronous API commands provide a simple and powerful way to write asynchronous applications which save wait time and frees up your program to continue with other processing.
Event processing overview
An event is anything that happens that is significant to an enterprise. Event processing is the capture, enrichment, formatting and emission of events, the subsequent routing and any further processing of emitted events (sometimes in combination with other events), and the consumption of the processed events.
FEPI concepts and facilities
This topic gives an overview of FEPI, and some general information about functions, services, and implementing applications.
Platforms in a cloud environment
Platforms are CICS resources that provide a layer of abstraction to decouple applications from the underlying region topology. A platform contains one or more region types, each of which contains one or more CICS regions. For agile service delivery, an application can be dynamically deployed to the relevant region types within a platform, and removed again when no longer needed. Platforms can be used to deploy policies, to limit and control resources, and to provide application separation.
Cloud enabled CICS applications
The large set of resources that make up a business application within CICS can be logically defined as a single entity and deployed on a platform as a single resource. An application that is defined in this way can then be managed as a single entity throughout its lifecycle, making CICS application management faster, easier, and less prone to error.
CICS policies
The behavior of CICS can be controlled during run time, based on predefined policies. CICS performs the action that is defined in the policy when all the conditions specified in the policy are met.
CICS intercommunication
CICS is often used as a single system with associated data resources and a network of terminals. However, CICS can also be used in a multiple-system environment, in which it can communicate with other systems that have similar communication facilities. This sort of communication is called CICS intercommunication.
CICS web support
CICS web support is a collection of CICS services that enable a CICS region to act both as an HTTP server, and as an HTTP client.
CICS and web services
CICS provides support for web services.
CICS external interfaces
CICS provides a number of interfaces that make transaction processing services available to a variety of external users.
Access to databases and data sets
CICS supports access to external data in DB2® and DL/I databases and in VSAM and BDAM data sets.
CICSPlex SM overview
The CICSPlex® System Manager element of CICS Transaction Server for z/OS® is a system management tool that enables you to manage multiple CICS systems from a single control point.
CICS and Business Transaction Services (BTS)
Read this introductory information to learn about CICS business transaction services (BTS).
CICS and MQ
CICS provides two interfaces to allow you to bring workload into CICS using MQ messages. These interfaces are the CICS-MQ adapter and the CICS-MQ bridge.
CICS feature toggles and continuous delivery
CICS TS continuous delivery delivers new functional enhancements on a much shorter cadence, providing much more rapid access to those new features. Usually, these features are not CICS base functions and are disabled by default. To enable and use these features in your CICS region, you must configure feature toggles when you set up the CICS region. With this feature toggling mechanism, you have great flexibility and control in enablement of such features.
Provisioning CICS with z/OS Provisioning Toolkit
With the IBM z/OS Provisioning Toolkit, application developers can independently, and rapidly, provision and deprovision a development environment without needing mainframe administration skills or authorities. System programmers can automate the provisioning process while retaining control by using IBM z/OS Management Facility (z/OSMF) workflows. Sample images for provisioning commonly used CICS environments such as CICS TS with an embedded Liberty JVM server, or standard CICS TS for traditional COBOL development, are provided with the z/OS Provisioning Toolkit.
Threadsafe learning path
This learning path provides an overview of open transaction environment (OTE) threadsafe options. Using the OTE you can obtain throughput improvements on multiprocessors, providing that the application code is threadsafe. The options available to get different types of threadsafe applications to use the OTE are explained and a summary is provided with links to further reading.
Managing and monitoring your CICS workload
This learning path provides an overview of the CICS and z/OS components, and some separate tools, which you can use for workload management and performance monitoring of your CICS regions. The primary audience for the learning path is CICS system administrators, and anyone who is involved with managing or assessing the performance of a CICS system.
Sysplex optimized workload management learning path
Sysplex optimized workload management takes advantage of the z/OS Coupling Facility (CF) to store current region status information posted directly from CICS. The stored region status is then used to make more efficient routing decisions. In this learning path, you learn about optimizing your workloads by implementing a region status (RS) server, the benefits you can expect, how to determine your optimization status, storage utilization, impact on the coupling facility, and RS server tuning parameters.