Job Entry Subsystem 1

Job Entry Subsystem (JES), aka Job Entry Subsystem 1 (JES1), was released by IBM as an integral part of OS/VS1 as an enhancement to the basic functions that users of VS1's predecessor, MFT, had.

IBM proclaimed JES1 to be "the single most important addition" to the job scheduling provided by VS1. IBM Systems Journal defined JES1's services as Spooling and scheduling, adding "Its three major components are peripheral services, central services, and queue management."

JES1 was not popular, because HASP and ASP users often had made local modifications (edits), and wanted to retain their investment.

JES1 permitted operators to submit batch jobs from local unit record equipment.

In addition, Remote Entry Service (RES) permitted remote operators to submit jobs from remote sites to JES. The printed and punched output of jobs running on OS/VS1, whether submitted locally or remotely, is handled by JES and may be routed to local devices, to the originating site or to another remote site. The Remote Entry Services (RES) of OS/VS1 is similar to Remote Job Entry (RJE) on OS/360 but the protocol for programmable workstations is that used by HASP II and ASP rather than that used by RJE.

• In MFT a reader or writer task tied up a partition; in JES1 a separate partition was required only while starting or stopping the task.
• In MFT each SPOOL file was a separate physical sequential (PS) dataset on public DASD; in JES1 SPOOL files are kept in a common SPOOL dataset managed by JES1.
• In MFT a reader task could be delayed by interpreting tasks; in OS/VS1 the interpretation is done when the job is initiated.
• The JOB Card JCL was given a new option: TYPRUN=SCAN, whereby a job could be submitted for quick feedback, and - if no errors were detected - be submitted again (without TYPRUN=SCAN on the JOB Card.
• JES1 used a SubSystem Interface (SSI) similar to that in MVS.