Many configurations take advantage of JES2's ability to link processors together to form a multiple-processor complex, which is generally referred to as a multi-access spool (MAS) configuration. A multi-access spool configuration consists of two or more JES2 (MAS) processors at the same physical location, all sharing the same spool and checkpoint data sets. There is no direct connection between the processors; the shared direct access data sets provide the communication link. Each JES2 processor can read jobs from local and remote card readers, select jobs for processing, print and punch results on local and remote output devices, and communicate with the operator. Each JES2 processor in a multiple processor complex operates independently of the other JES2 processors in the configuration.

The JES2 processors share a common job queue and a common output queue, which reside on the checkpoint data sets. These common queues enable each JES2 processor to share in processing the installation's workload; jobs can run on whatever processor is available and print or punch output on whatever processor has an available device with the proper requirements. Users can also specifically request jobs to run on a particular processor and output to print or punch on a specific device. If one processor in the configuration fails, the others can continue processing by selecting work from the shared queues and optionally take over for the failed processor. Only work in process on the failed processor is interrupted; the other JES2 systems continue processing.