JES2

Job Entry Subsystem 2

Please! Verify all details or suggestions with the appropriate vendor and / or vendor's manuals.

MVS uses a job entry subsystem (JES) to receive jobs into the operating system, schedule jobs for processing by MVS, and control job output processing. JES2 (job
entry subsystem 2) is descended from HASP (Houston automatic spooling priority), which is defined as a computer program that provides supplementary job
management, data management, and task management functions such as: scheduling, control of job flow, and spooling. HASP persists within JES2 as the prefix string for
most module names and for all messages sent by JES2 to the operator.

JES2 accepts the submission of work for the BCP and exercises independent control over its job processing.

SA32-0988-00 Network Job Entry (NJE) Formats and Protocols PDF

SA32-0987-00 z/OS JES Application Programming PDF

SA32-0990-00 z/OS JES2 Commands PDF

GA32-0993-00 z/OS JES2 Diagnosis PDF

SA32-0991-00 z/OS JES2 Initialization and Tuning Guide PDF

SA32-0992-00 z/OS JES2 Initialization and Tuning Reference PDF

SA32-0995-00 z/OS JES2 Installation Exits PDF

SA32-0994-00 z/OS JES2 Introduction PDF

SA32-0996-00 z/OS JES2 Macros PDF

SA32-0989-01 z/OS JES2 Messages PDF

Website

z/OS V1R12.0 Introduction and Release Guide
GA22-7502-18
Website

JES2 compared to JES3

z/OS concepts
IBM^® provides two kinds of job entry subsystems: JES2 and JES3. In many cases, JES2 and JES3 perform similar functions, but most installations use JES2.
Both JES2 and JES3 read jobs into the system, convert them to internal machine-readable form, select them for processing, process their output, and purge them from the system.
Some principle differences between the two JES systems include:

In a mainframe installation that has only one processor, JES3 provides tape setup, dependent job control, and deadline scheduling for users of the system, while JES2 in the same system would require its users to manage these activities through other means. In an installation with a multiprocessor configuration, there are noticeable differences between the two, mainly in how JES2 exercises independent control over its job processing functions. That is, within the configuration, each JES2 processor controls its own job input, job scheduling, and job output processing.

In cases where multiple z/OS^® systems are clustered (a sysplex), it is possible to configure JES2 to share spool and checkpoint data sets with other JES2 systems in the same sysplex. This configuration is called Multi-Access Spool (MAS). In contrast, JES3 exercises centralized control over its processing functions through a single global JES3 processor. This global processor provides all job selection, scheduling, and device allocation functions for all of the other JES3 systems.
With JES3, installations may decide whether the global JES3 or z/OS base control program will handle device allocation. With JES2, only the z/OS base control program handles device allocation.

JES3 differs from JES2 in two main processing areas:

JES3 exercises centralized control over its job processing functions. JES2 exercises independent control. With JES3, a single, global processor controls job, device, and workflow for all processors in a multi-processor environment.
JES3 does pre-execution of job setup. JES2 does not do this.

Website

Go to the JES3 page

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