Chapter 18: Printing

Since the inception of networking, printing has been a primary concern during the design and implementation phases of building networks. Whether the issue is quality of the print job, bandwidth needs, performance requirements, paper tray demystification, or simply determining "Where did my print job go?" administrators have struggled with providing secure, fast, and simple printing solutions to their users. This chapter explains the Windows printing environment, shows the options available to administrators within Presentation Server, defines terminology unique to Presentation Server printing, and provides a troubleshooting section for systematic resolution of the most common problems. Third-party print driver utilities are also discussed as alternatives for managing the Terminal Server/Presentation Server print environment beyond the tools inherent in Presentation Server 4.

WINDOWS PRINTING EXPLAINED

From the perspective of most users, printing is a very simple process. Type some text into an application, press the printer icon in the toolbar, and pick up the pages from the printer. Unfortunately, things aren't so simple for a system administrator. Devoting just a bit of thought to the difficulties of printing in complex environments is enough to give the average administrator a headache . In a less complex printing environment, the client computer, print server, and printer (or "print device" if you are fluent in Microsoft-speak) are typically all located in a single well-connected LAN environment. When printer problems occur, an administrator is able to walk to all of the devices involved in the print process to investigate and troubleshoot problems. As companies grow, expanded LANs and WANs complicate printing. The print server, client, and printer may all be on different segments of the network with some components located at different physical sites.

In a Terminal Server/Presentation Server environment these three key components (client, printer server, and printer) are often located across WAN links. New concepts and new terms also exist in a Presentation Server environment, which must be considered in order to effectively design, implement, and maintain that environment. Printing problems cause end- user frustration and, in turn , cause users to reject the new technology. With proper planning, testing, consideration, and a good troubleshooting methodology, however, Presentation Server printing can be managed and work properly.

The Windows Print Process

The Windows environment effectively shields the end user from the complexities of the print process. However, to appreciate the difficulty of developing and maintaining a complex and robust print environment, an administrator must understand the fundamentals of the print process.

When a Windows user clicks the print icon, the following occurs:

  1. The application generates an output file including document formatting called an enhanced metafile (EMF).

  2. The EMF is sent to the local print spooler.

  3. From the EMF file, the local print spooler generates a spool file using a print driver. The spool file includes printer-specific information needed by the printer to create the final document.

  4. The print job is queued by the print spooler in the local spool folder and forwarded to the printer or print server, where it is transformed from print commands to hard output.

In Presentation Server environments the Presentation Server server acts like a regular client workstation during printing to a standard network printer. The application running from the terminal server generates the EMF, the EMF file is sent to the local print spooler, and a spool file is generated. The spool file may then be sent directly to the printer, or to the print server that holds the queue for that printer.

When the Presentation Server server is printing to a local printer attached to a client machine, the process can be very different. If the client printer is using a standard print driver, on the server side, it will process the print job locally and then stream it to the client spooler. If the client printer is using the Universal Print Driver on the server, then the Citrix Print Manager service intercepts the spool file, compresses the file, and sends it to the client. The Win32 Presentation Server client then uncompresses the file and hands it to the local print spooler in native EMF format. This is a new process created for Presentation Server 4 and is very different from previous versions of the Universal Print Driver.



Citrix Access Suite 4 for Windows Server 2003. The Official Guide
Citrix Access Suite 4 for Windows Server 2003: The Official Guide, Third Edition
ISBN: 0072262893
EAN: 2147483647
Year: 2004
Pages: 137

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