Spooler Programmer's Guide

Introduction to the Spooler Subsystem
Spooler Programmer’s Guide—522287-002
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Disk Files Maintained by the Spooler
Disk Files Maintained by the Spooler
The spooler maintains two sets of disk files: data files and control files.
Data files are unstructured files containing the spooled data from all the jobs in the
spooler subsystem. Each collector has its own data file to hold jobs written to it. The
collector maintains an internal structure in the data file to ensure the integrity of jobs
and most efficiently use the storage space. The spooler library print routines are used
to fetch jobs from the collector data file. You can create data files at any time prior to
starting the collector.
Control files contain information regarding the attributes of all components of the
spooler: devices, processes, jobs, and so on.
The control file name has the same form as a disk file name. The control file name you
supply when you start the spooler is used to create these control files. You can specify
only seven letters or digits in the control file name; the spooler appends a integer
(0 through 9) to the control file name you specified. All 10 control file names should be
reserved for use by the spooler.
A particular control file defines a particular spooler subsystem. When a spooler has
been brought to an orderly halt (by means of the Spoolcom command SPOOLER
DRAIN), you can always restart it without any initialization by passing the control file
name to the supervisor (using the SPOOL command).
See the Guardian System Operations Guide for more information on how data file
names and control file names are selected and assigned.
Multiple Spoolers
The spooler can handle up to 8191 jobs and 511 output devices at one time, which
should suffice for most applications. However, if you need more spooling capability,
you can run any number of spooler subsystems at the same time.
To create additional spooler subsystems, simply follow the starting procedure as many
times as needed, each time using a different control file name and process name.
When running multiple spoolers, you should consider the following:

Spoolcom communicates with the spooler supervisor designated by the Spoolcom
OPEN command. The default supervisor name is $SPLS.

A spooler is always characterized by its control file. When a spooler is stopped
and then restarted, the control file name (not the process name of the spooler
supervisor) determines which spooler gets started.

Ensure that all collector and print process names are unique across all spooler
subsystems created on a given system. The presence of duplicate collector or
print process names is not immediately apparent when multiple spoolers are
starting. As long as the supervisor names are unique, all of the spooler
subsystems will start without error. However, nonunique collector or print process