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When a computer sends a document to a
printer for output, the information must be translated from the
operating system format to the Page Description Language
(PDL) of
the printer. The PDL then creates a raster (bitmap) image of the
document, and the printer outputs the image. These language
translations and the drawing of the raster image can be very time
consuming. A method of speeding up print jobs is through the use of host-based
printing.
Host-based printing, also known as Graphical Device Interface (GDI) printing, is a technology in which the operating system communicates directly with the printer and sends the printer an image that is ready to print. Since no translations need to be made and since the computer sends the data to the printer at the rate it is actually printed out, the speed of the printing process is significantly improved. Printers that take advantage of host-based printing technology are usually more inexpensive than traditional PDL-based printers. Because the computer CPU and memory are doing all of the work, manufacturers no longer have to place complicated processors or memory buffers on their printers. Therefore, host-based printing technology takes advantage of the power of the computer and the efficiency of the operating system. To increase the performance of the printer, users can upgrade the PC and update the printer driver. Along with the advantages of host-based printing technology, there are some drawbacks. A printer-specific driver must be installed. Many PDL-based printers can use generic drivers, while GDI printers must be specific for that particular model so the operating system will know how to communicate with the printer. Also, host-based printers placed on a network require that they are directly connected to a host and that printer sharing is configured. This host then becomes a print server, which may limit the role the computer can perform. |