Spooled files

Spooling is a system function that saves data for later processing or printing. This data is stored in a spooled file. Spooled files work in a similar manner to tape files or other device files. Spooled files allow you to manage your data targeted for externally attached devices such as a printer.

A spooled file holds output data until it can be printed. The spooled file collects data from a device until a program or device is able to process the data. A program uses a spooled file as if it were reading from or writing to an actual device.

Spooling functions help server users to manage input and output operations more efficiently. The server supports two types of spooling, output spooling and input spooling. Output spooling can be used for printer devices. Input spooling applies to database file input.

At the end of a the job, the job log can be written to the spooled file QPJOBLOG so that it can be printed. After the job log is written to the spooled file, the job log is deleted.

For information about using spooled files with printer output, see Spooled files in the Basic Printing topic.

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• Output spooling
  Output spooling can be used for both printer and diskette devices. Output spooling sends job output to disk storage instead of sending it directly to a printer or diskette output device. Output spooling allows the job that produces the output to continue processing without consideration for the speed or availability of output devices.
• Output queues and spooled files
  Batch and interactive job processing can result in spooled output records that are to be processed on an output device, such as a printer or diskette drive. These output records are stored in spooled files until they can be processed. There can be many spooled files for a single job.
• Default server output queues
  The server is shipped with the defaults on commands to use the default output queue for the server printer as the default output queue for all spooled output. The server printer is defined by the QPRTDEV server value.
• Spooling writers
  A writer is an i5/OS™ program that takes spooled files from an output queue and produces them on an output device. The spooled files that have been placed on a particular output queue will remain stored in the server until a writer is started to the output queue.
• Summary of spooling writer commands
  There are many commands that you can use to control spooling writers.
• Input spooling
  Input spooling takes the information from the input device, prepares the job for scheduling, and places an entry in a job queue. Using input spooling, you can typically shorten job run time, increase the number of jobs that can be run sequentially, and improve device throughput.
• Summary of job input commands
  The following commands may be used when submitting jobs to the server. The start reader commands may be used for spooling job input; the submit job commands do not use spooling. For detailed descriptions of these commands, see the CL topic in the iSeries™ Information Center.
• Use an inline data file
  An inline data file is a data file that is included as part of a batch job when the job is read by a reader or a submit jobs command. You use SBMDBJOB or STRDBRDR to queue up a CL batch stream (stream of CL commands to be executed or run). That CL batch stream can include data to be placed into "temporary" files (inline files). When the job ends, the inline files are deleted.
• Open considerations for inline data files
  The following considerations apply to opening inline data files: