How Local Printing Works

The print request follows the same path it would if the client and server were separate systems. Requests always flow from client to server following the same path.

The following figure shows what happens when a user submits a request to print a PostScript file on a local printer, which is a printer connected to the user's system. The lpsched daemon on the local system does all processing, which might include matching the printer and content type, identifying the default printer, filtering the request, and starting the specified printer interface program.

The printer interface program does the following:

• Prints the banner page.

• Catches printer faults.

• Determines the printer fault policy to either reset, continue, or begin the print job over again.

• Finally, the interface program uses the lpcat program to download the print request to the local printer's serial port.

Figure 8–2 The Local Printing Process