5.6 Chapter 32. CICS interface to JES
CICS provides a programming interface to JES (the Job Entry Subsystem component of MVS) that allows CICS applications to create and retrieve spool files. Spool files are managed by JES and are used to buffer output directed to low-speed peripheral devices (printers, punches, and plotters) between the job that creates them and actual processing by the device. Input files from card readers are also spool files and serve as buffers between the device and the jobs that use the data.
The interface consists of five commands:
- SPOOLOPEN INPUT, which opens a file for input
- SPOOLOPEN OUTPUT, which opens a file for output
- SPOOLREAD, which retrieves the next record from an input file
- SPOOLWRITE, which adds one record to an output file
- SPOOLCLOSE, which closes the file and releases it for subsequent
processing by JES
These commands can be used with either the JES2 or JES3 form of JES, although some restrictions apply to each (see "Spool interface restrictions" in topic 5.6.1.5). The term JES refers to both.
You can use the spool commands to do the following types of things:
- Create an (output) file for printing or other processing by JES. JES
manages most of the "unit record" facilities of the operating system,
including high-speed printers, and card readers. In order to use these
facilities, you pass the data to be processed to JES in a spool file.
- Submit a batch job to MVS. Spool files directed to the JES "internal
reader" are treated as complete jobs and executed.
- Create an (output) file to pass data to another job (outside of your
CICS), that runs under MVS.
- Retrieve data passed from such a job.
- Create a file to pass data to another operating system, such as VM,
VSE/ESA, or an MVS system other than the one under which your CICS is
executing.
- Retrieve a file sent from such a remote system.
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