Filter
Top Products
•
RPG II is not a supported language for CICS/OS. RPG II programs should be
converted to a supported application language (that is, COBOL, PL/I, C++,
and or Assembler).
•
Programs that directly invoke operating system services.
•
Programs that directly access operating system control blocks.
•
Programs that access internal CICS control blocks (DSECTs).
•
The CICS/VSE Report Controller Feature (RCF) is not supported by
CICS/MVS. This includes many suboperands of the EXEC CICS SPOOL
commands. The basic spool interface (open, close, read, and write) functions
are available in both CICS/VSE and CICS/MVS.
•
The CICS provided programming interface to JES (the Job Entry Subsystem
component of MVS) 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.
Spool Interface restrictions
There are internal limits in JES that you should consider when you are
designing applications. Some apply to JES2, some to JES3 and some to
both. In particular:
JES2 imposes an upper limit on the total number of spool files that a
single job (such as CICS) can create. If CICS exceeds this limit during its
execution, subsequent SPOOLOPEN OUTPUT commands fail with the
error condition.
JES3 does not impose such a limit explicitly, but for both JES2 and JES3,
some control information for each file created persists for the entire
execution of CICS. For this reason, creating very large numbers of spool
files can stress JES resources.
Spool files require other resources (buffers, queue elements, disk space)
until they are processed. Please review the
CICS Application
Programming Guide
for more details.
However, spool read is single thread in CICS/MVS. This may have
significant performance implications. Similar functions may be provided
in the MVS environment by the Report Management and Distribution
System (RMDS), 5665-310.
•
If your CICS applications have exploited the menu services provided by the
VSE Interactive Interface (II) they may need some rework. The II selection
panels and II programs such as IESFPIP do not exist in CICS/ESA. The
functions may be provided by user written CICS programs and maps. Similar
Chapter 6. CICS 151