Nowadays, the most common use of spooling is printing:
documents formatted for printing are stored in a queue at the speed of the computer, then retrieved and printed at the speed of the printer. Multiple processes can write documents to the spool without waiting, and can then perform other tasks, while the "spooler" process operates the printer. For example, when a large organization prepares payroll cheques, the computation takes only a few minutes or even seconds, but the printing process might take hours. If the payroll program printed cheques directly, it would be unable to proceed to other computations until all the cheques were printed. Similarly, before spooling was added to
PC operating systems,
word processors were unable to do anything else, including interact with the user, while printing. Spooler or print management software often includes a variety of related features, such as allowing priorities to be assigned to print jobs, notifying users when their documents have been printed, distributing print jobs among several printers, selecting appropriate paper for each document, etc. A
print server applies spooling techniques to allow many computers to share the same printer or group of printers.
Banner page Print spoolers can be configured to add a
banner page, also called a
burst page,
job sheet, or
printer separator, to the beginning and end of each document and job. These separate documents from each other, identify each document (e.g. with its
title) and often also state who printed it (e.g. by
username or
job name). Banner pages are valuable in office environments where many people share a small number of printers. They are also valuable when a single job can produce multiple documents. Depending on the configuration, banner pages might be generated on each client computer, on a centralized print server, or by the printer itself. On printers using fanfold
continuous forms a leading banner page would often be printed twice, so that one copy would always be face-up when the jobs were separated. The page might include lines printed over the fold, which would be visible along the edge of a stack of printed output, allowing the operator to easily separate the jobs. Some systems would also print a banner page at the end of each job, assuring users that they had collected all of their printout. == Other applications ==