IS - Information Systems

Enhanced Definition

In the mainframe context, an Information System (IS) refers to the comprehensive, integrated set of hardware, software, data, processes, and people designed to collect, process, store, and distribute information to support an organization's operations, management, and decision-making. It represents the entire computing ecosystem built upon the z/OS platform to deliver critical business functions.

Key Characteristics

- High Reliability and Availability: Mainframe-based IS are engineered for continuous 24/7 operation, often leveraging sysplex and parallel processing capabilities to minimize downtime and ensure business continuity.
- Scalability and Performance: Capable of handling immense transaction volumes (billions of transactions per day) and processing vast amounts of data, scaling dynamically to meet peak demands without degradation.
- Robust Security: Features multi-layered security built into the hardware, z/OS operating system, and security software like RACF, providing unparalleled data protection and access control.
- Centralized Data Management: Often manages an organization's most critical and sensitive data using high-performance database management systems like DB2 for z/OS and IMS DB.
- Hybrid Workload Support: Efficiently supports both high-volume batch processing for end-of-day reports and real-time online transaction processing (OLTP) via subsystems like CICS and IMS TM.
- Legacy and Modern Integration: While often hosting mission-critical legacy applications, mainframe IS are increasingly integrated with modern distributed and cloud environments through APIs and middleware.

Use Cases

- Core Banking Systems: Managing customer accounts, processing financial transactions, handling loans, and supporting ATM networks globally.
- Insurance Policy Administration: Processing claims, managing policy lifecycles, calculating premiums, and maintaining customer records for large insurance carriers.
- Airline Reservation Systems: Providing real-time booking, ticketing, flight scheduling, and passenger management for major airlines worldwide.
- Government Tax Processing: Handling vast amounts of taxpayer data, processing tax returns, and managing revenue collection for national and regional governments.
- Enterprise Resource Planning (ERP): Supporting large-scale manufacturing, supply chain management, and human resources functions for global corporations.

Related Concepts

An Information System on the mainframe is the overarching construct that encompasses the z/OS operating system, the zSystems hardware, and key subsystems like CICS, DB2, IMS, and MQ. It is built using programming languages such as COBOL and PL/I, orchestrated by JCL, and secured by RACF. Essentially, the IS is the complete solution that these individual components collectively form to deliver business value.

Best Practices:

Implement High Availability (HA) and Disaster Recovery (DR): Design the IS with sysplex data sharing, remote mirroring (GDPS), and robust DR plans to ensure continuous operation and data integrity.
Optimize Performance: Regularly tune JCL, COBOL programs, DB2 queries, and CICS transactions to maximize throughput and minimize resource consumption.
Enforce Strict Security Policies: Utilize RACF (or equivalent) to manage user access, implement data encryption for sensitive information, and conduct regular security audits.
Maintain Comprehensive Monitoring: Deploy robust monitoring tools for z/OS, CICS, DB2, and other subsystems to proactively identify and resolve performance bottlenecks or potential issues.
Adopt Modernization Strategies: Integrate mainframe IS with contemporary technologies through APIs, z/OS Connect EE, and hybrid cloud solutions to extend their reach and leverage new capabilities.