Hosted - Running on system

Enhanced Definition

"Hosted - Running on system" on the mainframe refers to the execution of applications, services, or workloads directly on the IBM z/Architecture hardware, managed by the z/OS operating system or a virtualized environment like z/VM. It signifies that the mainframe system provides the complete environment, resources, and infrastructure required for the software to run and operate.

Key Characteristics

- Execution Environment: Applications are hosted within specific z/OS environments such as CICS regions, IMS control regions, DB2 subsystems, or as batch jobs managed by JES.
- Resource Management: z/OS's Workload Manager (WLM) dynamically manages and allocates CPU, memory, I/O, and other system resources to hosted applications based on predefined service level objectives.
- High Availability & Reliability: Mainframe hosting inherently provides enterprise-grade availability, disaster recovery capabilities, and fault tolerance through features like Parallel Sysplex, data sharing, and robust hardware design.
- Security: Hosted applications benefit from z/OS's comprehensive security framework, including RACF (Resource Access Control Facility) for authentication, authorization, and auditing of access to system resources and data.
- Scalability: The z/OS platform offers vertical and horizontal scalability, allowing hosted applications to scale up by utilizing more processor capacity or scale out across multiple LPARs in a Parallel Sysplex.
- Integration: Hosted applications often integrate tightly with other mainframe services and data sources, such as DB2, IMS DB/DC, VSAM, and other z/OS middleware.

Use Cases

- Core Business Applications: Hosting mission-critical applications like banking transactions, insurance policy processing, airline reservations, and government services directly on z/OS.
- Database Management Systems: Running enterprise-scale database systems such as DB