4.2BSD Line Printer Spooler Manual

This document is the 4.2BSD Line Printer Spooler Manual, published in May 1984 by Digital Equipment Corporation. It provides detailed information on the ULTRIX-32 line printer system, which supports multiple printers, spooling queues, and both local and remote printing, including specialized raster and laser devices.

The manual outlines the core components and commands of the system, including lpd (line printer daemon) for coordinating spooling, lpr for submitting print jobs, lpq for examining queues, lprm for deleting jobs, and lpc for administrative control. It explains the critical role of the /etc/printcap file for printer configuration and capability, as well as the use of output filters to manage device dependencies and accounting.

Key sections cover the implementation of access control for protected spooling areas, detailing how programs like lpr utilize setuid root and setgid spooling, and how remote clients are authenticated. It provides guidance on setting up the system, emphasizing printcap file creation and filter implementation, with examples for serial and remote printers. Finally, the manual includes a comprehensive troubleshooting section, explaining common error messages generated by the various line printer commands and offering solutions.