8. A computer for executing a printer processing method, the computer comprising: a mark-up language parsing unit for interpreting a mark-up language document written in a mark-up language; and a port control unit for controlling a communication port used for communication with a printer having multiple mechanisms including a cover, a paper cutter, and transportation unit to a transport a print-medium; wherein: the mark-up language parsing unit has a conversion unit for converting a first mark-up language document to binary data including a mechanism control command that can be processed by the printer and that controls to at least one of the paper cutter and the transportation unit, the mechanism control command being based on model-dependent information that is specific to the printer and defines a rule for converting the mark-up language document to the mechanism control command when the mark-up language document is input; the port control unit has an output unit for outputting the converted binary data to the printer, based on port information relating to the communication port; the port control unit further having an input unit for inputting status information related to at least one of the mechanisms and outputted from the printer as a binary data; the model-dependent information defines rules for converting the received, binary data, status information to a second mark-up language document; the first mark-up language document is an XML document output from a POS application running a transaction process and generating transaction data; and the mark-up language parsing unit further executes a status information conversion step for converting the received status information to the second mark-up language document based on the model-dependent information and outputting the second mark-up language document as an XML document to the POS application.
8. A computer for executing a printer processing method, the computer comprising: a mark-up language parsing unit for interpreting a mark-up language document written in a mark-up language; and a port control unit for controlling a communication port used for communication with a printer having multiple mechanisms including a cover, a paper cutter, and transportation unit to a transport a print-medium; wherein: the mark-up language parsing unit has a conversion unit for converting a first mark-up language document to binary data including a mechanism control command that can be processed by the printer and that controls to at least one of the paper cutter and the transportation unit, the mechanism control command being based on model-dependent information that is specific to the printer and defines a rule for converting the mark-up language document to the mechanism control command when the mark-up language document is input; the port control unit has an output unit for outputting the converted binary data to the printer, based on port information relating to the communication port; the port control unit further having an input unit for inputting status information related to at least one of the mechanisms and outputted from the printer as a binary data; the model-dependent information defines rules for converting the received, binary data, status information to a second mark-up language document; the first mark-up language document is an XML document output from a POS application running a transaction process and generating transaction data; and the mark-up language parsing unit further executes a status information conversion step for converting the received status information to the second mark-up language document based on the model-dependent information and outputting the second mark-up language document as an XML document to the POS application. 13. The computer described in claim 8 , further comprising: a storage unit storing the model-dependent information and the port information; a model-dependent data reception unit for accessing a server coupled to the computer and printer, and retrieving from the server the model-dependent information and port-communications information; and a port data reception unit for controlling the storing of the port information sent from the server into the storage unit.