Creating Printer Shares

Samba printer shares are very similar to file shares. The primary distinguishing characteristic is the printable = Yes option, which tells Samba to treat the share as a printer share. If this option is set, Samba tries to send files destined for the printer to a local print queue of the same name as the Samba printer share. (If you want to use another print queue name, you can set it with the printer option.)

Rather than define printers one by one, many Samba configurations rely on a special printer share name that's akin to the [homes] share for file shares: [printers]. This share might look something like this:

[printers] comment = All Printers browseable = no path = /tmp printable = yes create mode = 0700

If this share is present, and if the [global] section does not include a load printers = No option, Samba scans /etc/printcap (or another file defined by printcap name in the [global] section) and creates a printer share for every print queue on the system. This feature can be a convenient way to share all of your printers at once.

Samba delivers the print job via the local printing system—BSD LPD, LPRng, CUPS, or something more exotic if that's what you use. The global printing option defines how Samba submits print jobs, so be sure this option is set correctly. In all cases, the format of the job Samba submits must be something that the print queue can handle. Because Samba simply passes a file it receives from the client on to the server's printing system, this means that the client must have a print driver that generates output the Linux print queue can process. In most cases, Linux print queues are designed to handle PostScript input, so using a generic PostScript driver on the client is in order. As a general rule, drivers for Apple LaserWriter models work well for monochrome printers, and QMS magicolor PostScript drivers work well for color printers. Adobe also provides generic PostScript drivers at

http://www.adobe.com/support/downloads/, but these drivers are licensed only for use with printers that use genuine Adobe PostScript interpreters. If your printer is a PostScript model, you can try using the driver provided by the manufacturer. On occasion, though, these drivers create output that includes mode-switching codes that confuse Linux print queues, so you may need to use another driver. Alternatively, you can include the postscript = Yes option; this tells Samba to tack a PostScript identifier onto the start of the file, causing the Linux print queue to correctly identify the output as PostScript.

If your printer is a non-PostScript model, you can try using its native driver. This practice will only work if the Linux print queue recognizes the format and passes print jobs unmodified to the printer, though. If necessary, you can create a "raw" print queue, as described in Chapter 13, "Managing Printers," to pass data through without changes.

Note Many, but not all, printers that can't be made to work from Linux can still be served to Linux clients using Samba and a raw print queue. A few such printers rely on two-way communication between the printer and Windows printer driver. Such printers won't work via Samba unless they're supported in Linux.

In practice, it's hard to say which is better—to use Windows PostScript drivers with a Linux print queue that interprets PostScript using Ghostscript or the printer's native drivers in Windows and a raw queue. The PostScript approach is likely to reduce network traffic when printing text, but it imposes a greater CPU load on the print server. The native driver approach is likely to increase network traffic when printing text and shifts the CPU load onto the clients. The PostScript approach may be desirable if you use applications that work best with PostScript printers, such as some desktop publishing and graphics tools. Native drivers often give more convenient access to printer features such as resolution adjustments. Either approach could produce superior output; the best approach depends on the drivers in question and the type of printing. I recommend you try both approaches. You may want to create two queues, one for each method. (If your Linux queue is smart enough to recognize the file type, you'll need only one Samba printer share; you can create multiple queues on the clients that print to the same Samba share.)

Team LIB

Team LIB

^ previous

0 0

Post a comment