Specifications

3-5
Spooler Overview
• For print jobs, provides an environment that you can customize to address specific
printing needs.
You typically do not run printer backend programs directly, although backends such as
compilers can clearly be run directly from the command line. The qdaemon runs the
backend, sending it the names of files and any job control flags that you specify. The
backend communicates with the qdaemon through a status file in the /var/spool/lpd/stat
directory. You can use a queue status query command such as qchk or lpstat to display
status information, including, in the case of a print job, the printer status, the number of
pages printed, and the percentage of the job that is finished.
In the base operating system, piobe is the standard spooler backend for processing local
print jobs.
Spooler Job
A spooler job is any job that a user submits to the spooler. All job submission commands
must end with the names of one or more files that require processing. You cannot, for
example, pass a keyword to a backend and have the keyword control the function that
backend will perform; the submitted job must exist in the file system.
The spooler will accept many types of jobs. It is the responsibility of the system
administrator to ensure that the backend for a given queue is capable of processing any job
submitted to that queue.
Printer job types include:
• ASCII
• Postscript
• PCL
• HPGL
• GL
• Diablo 630
• ditroff