User`s guide

1-3
Printers, Print Jobs, and Queues Overview for Users
Real Printer
A real printer is the printer hardware attached to a serial or parallel port at a unique
hardware device address. The printer device driver in the kernel communicates with the
printer hardware and provides an interface between the printer hardware and a virtual
printer, but it is not aware of the concept of virtual printers.
Local and Remote Printers
When you attach a printer to a node or host, the printer is referred to as a local printer. A
remote print system allows nodes that are not directly linked to a printer to have printer
access.
To use remote printing facilities, the individual nodes must be connected to a network using
the Transmission Control Protocol/Internet Protocol (TCP/IP) and must support the required
TCP/IP applications.
Printer Backend
The printer backend is a collection of programs called by the spooler’s qdaemon command
to manage a print job that is queued for printing. The printer backend performs the following
functions:
• Receives from the qdaemon command a list of one or more files to be printed.
• Uses printer and formatting attribute values from the database, overridden by flags
entered on the command line.
• Initializes the printer before printing a file.
• Runs filters as necessary to convert the print data stream to a format supported by the
printer.
• Provides filters for simple formatting of ASCII documents.
• Provides support for printing national language characters.
• Passes the filtered print data stream to the printer device driver.
• Generates header and trailer pages.
• Generates multiple copies.
• Reports paper out, intervention required, and printer error conditions.
• Reports problems detected by the filters.
• Cleans up after a print job is canceled.
• Provides a print environment that a system administrator can customize to address
specific printing needs.