Multi-Access Spool

The MAS complex is a facility that increases the security of JES 2 and assists in the system recovery.

In a MAS, each systems keeps its internal queue consistent with the copy in the checkpoint data set. Because of this all processors logically will share the same queue.

In an event that one of the systems in the MAS complex fails, the other systems in the complex can use the shared checkpoint data of the shared spool in order to resume the jobs that it was processing.

In effect, all systems in the complex will have just one shared common spool. They are loosely coupled and the jobs can be sent into any system for execution.

Even in a MAS scenario, commands relating to jobs and queues entered on a system cannot affect local devices or JES initiators of another system.