Mainframe concepts
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Who is the system operator?

Mainframe concepts

The system operator monitors and controls the operation of the mainframe hardware and software. The operator starts and stops system tasks, monitors the system consoles for unusual conditions, and works with the system programming and production control staff to ensure the health and normal operation of the systems.

System console messages can be so voluminous that operators often have a difficult time determining whether a situation is really a problem. In recent years, tools to reduce the volume of messages and automate message responses to routine situations have made it easier for operators to concentrate on unusual events that might require human intervention.

As applications are added to the mainframe, the system operator is responsible for ensuring that they run smoothly. New applications from the Applications Programming Department are typically delivered to the Operations Staff with a run book of instructions. A run book identifies the specific operational requirements of the application, which operators need to be aware of during job execution. Run book instructions might include, for example:
  • Application-specific console messages that require operator intervention
  • Recommended operator responses to specific system events
  • Directions for modifying job flows to accommodate changes in business requirements

The operator is also responsible for starting and stopping the major subsystems, such as transaction processing systems, database systems, and the operating system itself. These "restart operations" are not nearly as commonplace as they once were, as the availability of the mainframe has improved dramatically over the years. However, the operator must still perform an orderly shutdown and startup of the system and its workloads, when it is required.

In case of a failure or an unusual situation, the operator communicates with system programmers, who assist the operator in determining the proper course of action, and with the production control analyst, who works with the operator to make sure that production workloads are completing properly.

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