Abstract for MVS Using the Functional Subsystem Interface

Who should read this information

This book is intended for anyone responsible for writing and installing a functional subsystem (FSS) and its functional subsystem applications (FSA). This book describes the functional subsystem interface (FSI) and shows how the FSS and a job entry subsystem (JES) communicate using the FSI.

How is this information organized

The organization and content of each section are:
  • Functional Subsystem Interface Concepts, briefly describes functional subsystem concepts, terminology, address space relationships, and services that the functional subsystem interface supplies.
  • An Overview of FSI Processing, describes the overall flow of processing from the time the FSS is started, through data set processing, until the FSS is terminated.
  • Installing a Functional Subsystem, provides examples of JES initialization statements needed to install a functional subsystem and a sample JCL procedure.
  • The FSIREQ Macro, presents the FSIREQ macro and explanations of the macro parameters.
  • FSI Communication, describes the communication mechanisms that allow JES to make service requests to the FSS or FSA and allows the FSS or FSA to respond to JES.
  • Establishing FSS/JES Communication, describes the processing for starting the functional subsystem.
  • Establishing FSA/JES communication, describes the processing for starting a functional subsystem application that is associated with an individual device.
  • Starting an FSS device, describes the processing for starting a device that runs under an FSS.
  • Issuing Data Requests to JES, describes how to obtain and free a data set and its records, and how to ask JES to record checkpoint information.
  • Responding to Device Orders From JES, describes the processing for orders that request a change in device or data set characteristics, affects the flow of data through the device, or requests information about a data set currently being processed by an FSA device.
  • Stopping an FSS device, describes the processing involved in stopping a device that is running under an FSS.
  • Stopping an FSA, describes the processing for stopping a functional subsystem application that is associated with an individual device.
  • Stopping an FSS, describes the processing for terminating the functional subsystem address space.
  • FSS Output Descriptor Support, describes the scheduler JCL facility and how it interfaces with JES and the FSS to provide FSS scheduler work block support.
  • FSI Trace, describes FSI trace facilities useful for diagnosing problems with the FSI.
  • FSIREQ Parameter List, contains storage representations for the fields in the IAZFSIP mapping macro and other related storage.
  • Numeric Values of FSI Services and Orders, provides the numeric values for the FSI services.

How to use this information

Use Functional Subsystem Interface Concepts, and An Overview of FSI Processing, to familiarize yourself with the terminology and processing related to the functional subsystem interface.

Use Installing a Functional Subsystem, to install the functional subsystem.

Then use The FSIREQ Macro, through FSS Output Descriptor Support, when you are coding your functional subsystem and your functional subsystem applications. These chapters explain how to use the FSI to make requests to JES and explains how JES will respond to those requests. These sections explain the values that JES expects to receive from your functional subsystem during processing. These sections also show the values that your functional subsystem can expect to receive from JES when your FSS receives control.

Use FSI Trace, to diagnose any problems your FSS encounters.