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
"Input" and "output" here refer to the CICS point of view
here; what is spool output to one job is always spool input to another job
or JES program.
These commands can be used with either the JES2 or JES3 form of JES, although
some restrictions apply to each (see Spool interface restrictions). The term JES
refers to both. You can support the requirements of other products to exchange
files with other systems connected through a JES remote spooling communications
subsystem (RSCS) network.
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. See Figure 93
Figure 93. Create a file and write it to the JES spool
- 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. See Figure 94
Figure 94. Retrieve data from the JES spool
- 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.
See Figure 95.
Figure 95. Send a written file to a remote destination
This chapter describes:
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