1. An XML printer system adapted to print bar code labels based upon an extensible markup language (XML) input data stream, the XML printer system including a printer apparatus having a media control system, a print head assembly, and a print head driver, the XML printer system comprising: a computer system operatively coupled to the printer apparatus; the computer system further including a memory subsystem; a communication interface operatively coupled to a network; an XML processor configured to receive and process the XML input data stream, and obtain schema identified in the XML data stream from a schema repository, the XML processor validating the XML data stream based upon the schema obtained; an extensible stylesheet language transformation (XSLT) processor configured to obtain a stylesheet identified in the XML data stream from a stylesheet repository, the XSLT processor transforming data in the XML input data stream into transformed XML data based upon the stylesheet obtained; an extensible stylesheet language formatting object (XSLFO) processor configured to format the transformed XML data into formatted XML data based upon XSLFO instructions contained in the stylesheet; and a barcode rendering subsystem configured to receive the formatted XML data and generate a bit map representative of the bar code label.