Abstract:
A method and system for downloading encrypted double-byte font scripts to a print server. A communication element is interposed between a data processing system and a print server, where the print server does not support a bi-directional communication protocol utilized by the data processing system to download encrypted double-byte font scripts. The communication element supports data transmissions in both the bi-directional communication protocol and with the print server. To download a double-byte font script, the data processing system transmits a request to the print server through the communication element for an identifier from the print server. The print server transmits the identifier to the data processing system through the communication element. A decryption key for the double-byte font script is produced by the data processing system utilizing the identifier and downloaded with the encrypted double-byte font script to the print server through the communication element.

Description:
BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The present invention relates in general to an improved method and system for downloading fonts, and in particular to a method and system for downloading encrypted font scripts to a print server. Still more particularly, the present invention relates to a method and system for downloading encrypted double-byte font scripts from a data processing system that utilizes a bi-directional communications protocol to a print server which does not support the bi-directional communications protocol. 
     2. Description of the Related Art 
     In the development of printer systems, page-description languages have been developed which offer flexible font capability and high-quality graphics for printing. Currently, the most-well known of the page-description languages is POSTSCRIPT, which is a trademark of Adobe Systems. POSTSCRIPT fonts have been developed which are defined in terms of the POSTSCRIPT page-description language rules and are intended to be printed on a POSTSCRIPT-compatible printer. 
     POSTSCRIPT compatible printers typically utilize an ADOBE POSTSCRIPT Interpreter to support printing of POSTSCRIPT fonts. Typically, in order to print characters defined in POSTSCRIPT fonts, a script describing each character of the POSTSCRIPT font is downloaded to the POSTSCRIPT-compatible printer where the ADOBE POSTSCRIPT Interpreter utilizes the script to translate a printing image for each POSTSCRIPT character. The scripts for fonts may be loaded into a memory of the printer or in a print server that is dedicated to managing printers on a network. In this manner, the scripting is provided at the printer to support the font, for subsequent requests for the POSTSCRIPT font. Additionally, some PostScript fonts are encrypted and the printer must access the font script utilizing a decryption key downloaded with the encrypted font. 
     In the development of data processing systems, multiple operating systems (OSs) have been developed. In designing new operating systems, it is typical to provide support for existing operating systems by the new operating system. For example, the MACINTOSH (MAC) OS utilizes Printer Access Protocol (PAP) to govern communications between computers and printers where one function of PAP is downloading font scripts. MAC OS is a trademark of Apple Computers Corporation. WINDOWS NT is an example of an operating system that provides support for PAP communication whereby WINDOWS NT systems and MAC OS systems may communicate to download font scripts. WINDOWS NT is a trademark of Microsoft Corporation. 
     However, not all operating systems are enabled to support PAP. For example, the AIX OS does not support PAP communication with the MAC OS. AIX OS is a trademark of International Business Machines Corporation. However, the AIX OS may be utilized to control a print server. Therefore, from a MACINTOSH system, via traditional PAP communication, new font scripts cannot be downloaded to a print server controlled by the AIX OS. 
     In the development of POSTSCRIPT fonts, characters which require two bytes per character to specify have been created. To support downloading these double-byte character POSTSCRIPT fonts, a double-byte character POSTSCRIPT font downloader (DBFD) has been provided which is compatible with the MAC OS. In particular, the DBFD supports downloading encrypted double-byte character POSTSCRIPT fonts to a printer or print server. In a general example, the DBFD software resides on a data processing system controlled by the MAC OS. The DBFD works by sending a request, via a PAP connection, to a POSTSCRIPT interpreter on a print server or printer with a request for at least one unique POSTSCRIPT interpreter identifier(ID). The POSTSCRIPT interpreter processes the request from the MACINTOSH and responds, via a PAP connection, to the MACINTOSH with at least one unique interpreter ID. The DBFD then utilizes the returned unique interpreter ID(s) to make a key for decrypting an encrypted POSTSCRIPT double-byte font script. Thereafter, the encrypted POSTSCRIPT double-byte font script and a decryption key are transmitted to the printer or print server where the encrypted POSTSCRIPT double-byte font script and the decryption key are stored. When the font is successfully downloaded, the POSTSCRIPT interpreter of the printer or print server may utilize the newly stored font script to print documents. 
     In some markets, MAC OS based systems access printers which are served by AIX based systems. In this case, there is a need for a method for downloading double-byte character fonts scripts and other custom fonts from the MAC OS based systems to the print server which is an AIX based system. In particular, there is a need for a method of communicating between a MAC OS based system which supports the DBFD software and an AIX OS based system which supports the PostScript interpreter. 
     SUMMARY OF THE INVENTION 
     In view of the foregoing, it is therefore one object of the present invention to provide an improved method and system for downloading font scripts. 
     It is another object of the present invention to provide an improved method and system for downloading encrypted font scripts onto a print server. 
     It is yet another object of the present invention to  1 provide an improved method and system for downloading encrypted double-byte font scripts from a data processing system that utilizes a bi-directional communications protocol to a print server which does not support the bi-directional communications protocol. 
     In accordance with the method and system of the present invention, a communication element is interposed between a data processing system and a print server, where the print server does not support a bi-directional communication protocol utilized by the data processing system to download encrypted double-byte font scripts. The communication element supports data transmissions in both the bi-directional communication protocol and with the print server. To download a double-byte font script, the data processing system transmits a request to the print server through the communication element for an identifier from the print server. The print server transmits the identifier to the data processing system through the communication element. A decryption key for the double-byte font script is produced by the data processing system utilizing the identifier and downloaded with the encrypted double-byte font script to the print server through the communication element. 
     All objects, features, and advantages of the present invention will become apparent in the following detailed written description. 
    
    
     DESCRIPTION OF THE FIGURES 
     The invention itself, as well as a preferred mode of use, further objects, and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein: 
     FIG. 1 depicts a block diagram of a typical computer system that may utilize a preferred embodiment of the present invention; 
     FIG. 2 illustrates a block diagram of a layer diagram of the software of the computer system of FIG. 1; 
     FIG. 3 depicts a block diagram of communications between a MAC OS based computer system and an AIX OS based computer system in accordance with the method and system of the present invention; and 
     FIG. 4 illustrates high-level logic flowchart of a process for transmitting data to and from a PAP connection and a POSTSCRIPT API socket in accordance with the method and system of the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the drawings and in particular to FIG. 1, there is depicted a block diagram of a typical computer system that may utilize a preferred embodiment of the present invention. As shown, a processor (CPU)  12 , a read-only memory (ROM)  13 , and a Random-Access Memory (RAM)  14  are connected to a system bus  11  of a computer system  10 . CPU  12 , ROM  13 , and RAM  14  are also coupled to a PCI local bus  20  of computer system  10  through a PCI host bridge  16 . PCI host bridge  16  provides a low latency path through which processor  12  may directly access PCI devices mapped anywhere within bus memory and/or I/O address spaces. PCI host bridge  16  also provides a high bandwidth path for allowing PCI devices to directly access RAM  14 . 
     Also attaching to PCI local bus  20  are communications adapter  15 , small computer system interface (SCSI)  18 , and expansion bus bridge  29 . Communications adapter  15  is utilized for connecting computer system  10  to a network  17 . SCSI  18  is utilized to control high-speed SCSI disk drive  19 . Expansion bus bridge  29 , such as a PCI-to-ISA bus bridge, may be utilized for coupling ISA bus  25  to PCI local bus  20 . As depicted, a keyboard  26  and a mouse  28  are attached to ISA bus  25  for performing certain basic I/O functions. In addition, an audio adapter  23  is attached to PCI local bus  20  for controlling audio output through speaker  24 . A graphics adapter  21  is also attached to PCI local bus  20  for controlling visual output through display monitor  22 . In alternate embodiments of the present invention, additional peripheral components may be added. 
     Computer system  10  also preferably includes an interface such as a graphical user interface (GUI) and an operating system (OS) that reside within machine readable media to direct the operation of computer system  10 . Any suitable machine-readable media may retain the GUI and OS, such as RAM  14 , ROM  13 , SCSI disk drive  19 , and other disk and/or tape drive (e.g. magnetic diskette, magnetic tape, CD-ROM, optical disk, or other suitable storage media). Any suitable GUI and OS may direct CPU  12 . For example, the AIX operating system is one of IBM&#39;s operating systems which may be implemented. 
     Further, computer system  10  preferably includes at least one software application (e.g. program product) that resides within machine readable media and may be loaded into RAM  14  and then into CPU  12  for execution. A software application contains instructions that when executed on CPU  12  carry out the operations depicted in the flow chart of FIG.  4  and others described herein. 
     Referring now to FIG. 2, there is illustrated a block diagram of a layer diagram of the software of computer system  10 . At the highest level of the diagram are the application programs  40 . At the intermediate level is an application program interface (API)  42 , through which the application programs request services from an operating system  44 . The lowest level of each diagram is occupied by operating system  44 . In addition to managing the operations of a computer system, operating system  44  also provides tools for managing communications between computer system  10  and remote data processing systems. Included in operating system  44  is a kernel  46  that manages the memory, files, and peripheral devices of computer system  10 . The lowest level also includes device drivers  48  that each kernel utilizes to manage input from and output to peripheral devices. 
     With reference now to FIG. 3, there is illustrated a block diagram of communications between a MAC OS based computer system and an AIX OS based computer system according to the method and system of the present invention. A MAC OS based data processing system  50  includes a double-byte font downloader (DBFD) application program  52 . DBFD application program  52  produces a request for at least one unique printer interpreter ID in order to produce a decryption key that will be downloaded with encrypted double-byte POSTSCRIPT fonts to a print server. Data processing system  50  transmits the request via a printer access protocol (PAP) connection which is utilized by the MAC OS for communication with printers and or print servers. The request is received at a communications element  54  interposed between data processing system  50  and print server  58 . In the present embodiment of the present invention, communication element  54  is supported by WINDOWS NT, includes a downloader daemon application program  56  and receives and transmits communications via at least one PAP connection and at least one POSTSCRIPT API socket. In alternate embodiments, communications element  54  may be supported by alternate operating systems, including alternate application programs and receive and transmit via alternate protocol interfaces. 
     Downloader daemon application program  56  routes the request to an AIX OS based print server  58  via a POSTSCRIPT API socket which provides for data transmission between communications element  54  and AIX OS based system. An ADOBE POSTSCRIPT Interpreter application program  60 , residing on AIX OS based print server  58 , receives the request and in turn produces at least one unique interpreter ID. At least one unique interpreter ID is passed to communication element  54  via the POSTSCRIPT API socket. Downloader daemon application program  56  routes at least one unique interpreter ID to data processing system  50  through the PAP connection. DBFD application program  52  produces a decryption key for an encrypted double-byte font script utilizing at least one unique interpreter ID. The encrypted POSTSCRIPT font and decryption key are transmitted to communication element  54  via the PAP connection. Downloader daemon application program  56  routes the encrypted POSTSCRIPT font and decryption key to print server  58  via the POSTSCRIPT API socket. Print server  58  stores the encrypted POSTSCRIPT font and decryption key for subsequent use. 
     Referring now to FIG. 4, there is illustrated high-level logic flowchart of a process for transmitting data to and from a PAP connection and a POSTSCRIPT API socket in accordance with the present invention. As depicted, the process starts at block  70  and thereafter proceeds to block  72 . Block  72  illustrates a determination as to whether or not there is data received via a PAP connection. If there is data received from a PAP connection, the process passes to block  74 . Block  74  depicts transmitting the data received from the PAP connection to the intended destination through a POSTSCRIPT API socket. Thereafter, the process proceeds to block  72 . 
     Returning to block  72 , if there is not data received via a PAP connection, the process passes to block  76 . Block  76  illustrates a determination as to whether data is received from a POSTSCRIPT API socket. If data is not received from a POSTSCRIPT API socket, the process passes to block  72 . If the data is received from a POSTSCRIPT API socket, the process passes to block  78 . Block  78  depicts transmitting the data received from the POSTSCRIPT API socket interface to the intended destination via a PAP connection. Thereafter, the process proceeds to block  72 . 
     As has been described, the invention provides a method for downloading POSTSCRIPT fonts from a MAC OS based system to an AIX OS based system through a WINDOWS NT based system. Although the downloader daemon application program in the WINDOWS NT based system provides a communication method between the incompatible systems, other systems with operating systems that support both PAP and POSTSCRIPT API socket interface communication may be utilized. In addition, while the invention is described for a double-byte font downloader application program, other types of font downloader application programs may also be implemented by the method of the present invention. 
     This invention is described in a preferred embodiment in the following description with reference to the figures, in which like numbers represent the same or similar elements. While this invention is described in terms of the best mode for achieving this invention&#39;s objectives, it will be appreciated by those skilled in the art that variations may be accomplished in view of these teachings without deviating from the spirit or scope of the present invention. For example, the present invention may be implemented using any combination of computer programming software, firmware or hardware. As a preparatory step to practicing the invention or constructing an apparatus according to the invention, the computer programming code (whether software or firmware) according to the invention will typically be stored in one or more machine readable storage mediums such as fixed (hard) drives, diskettes, optical disks, magnetic tape, semiconductor memories such as ROMs, PROMs, etc., thereby making an article of manufacture in accordance with the invention. The article of manufacture containing the computer programming code is used by either executing the code directly from the storage device, by copying the code from the storage device into another storage device such as a hard disk, RAM, etc. or by transmitting the code on a network for remote execution. The method form of the invention may be practiced by combining one or more machine readable storage devices containing the code according to the present invention with appropriate standard computer hardware to execute the code contained therein. An apparatus for practicing the invention could be one or more computers and storage systems containing or having network access to computer program(s) coded in accordance with the invention. 
     While the invention has been particularly shown and described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention.