Understanding CICS: A Comprehensive Overview
CICS (Customer Information Control System) is a powerful transaction processing subsystem designed for the z/OS operating system. It enables organizations to run online applications with exceptional performance, reliability, and scalability.
Key Features of CICS
- Resource Management: Efficiently shares and manages system resources
- Data Integrity: Ensures consistent and secure data processing
- High Performance: Supports rapid transaction processing for enterprise applications
- Multi-User Support: Enables simultaneous access by multiple users
CICS in the z/OS Ecosystem
Within the z/OS system, CICS acts as a specialized layer for transaction management. It isolates and handles online application programs, providing a robust interface between application logic and system hardware.
System Integration
- Separates online applications from other system programs
- Provides direct interfaces with database managers like DB2
- Manages resource allocation and user authorization
CICS Transactions and Programs
A CICS application represents a collection of interconnected programs designed to execute specific business operations. These can range from processing travel requests to managing complex payroll systems.
Transaction Processing Workflow
- Execute one or more application programs
- Handle message transmissions between applications and terminals
- Manage file and database access requests
Programming Language Support
CICS offers remarkable flexibility by supporting multiple programming languages, allowing developers to leverage their existing skills and preferred development environments.
Supported Languages
- COBOL
- Object-Oriented COBOL
- C
- C++
- Java
- PL/I
- Assembler
Transaction Programming Paradigms
CICS supports different transaction programming approaches to meet diverse application requirements.
Transaction Types
- Conversational Transactions: Interactive programs that maintain an ongoing dialogue with users
- Non-Conversational Transactions: Single-input, immediate-response transactions that complete quickly