Abstract:
Techniques are provided for extending a WS-enabled scanner. A client device sends a request for multiple scan ticket templates that the WS-enabled scanner maintains. A WS scan module, executing on the scanner, receives the request and forwards the request to a scan templates handler (STH). The STH invokes a routine of a scan templates manager (STM). The STM retrieves, in response to the invocation of the routine, a plurality of scan ticket templates. The STM sends the plurality of scan ticket templates to the STH, which forwards the plurality to the WS scan module. The WS scan module composes a response message that includes the plurality of scan ticket templates and sends the response message to the client device.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to extending a Web service scan service to support the maintenance of multiple scan ticket templates. 
       BACKGROUND 
       [0002]    The approaches described in this section are approaches that could be pursued, but not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated, it should not be assumed that any of the approaches described in this section qualify as prior art merely by virtue of their inclusion in this section. 
         [0003]    A scan ticket is a set of scan settings for scanning a document. The scan settings dictate how a document is to be scanned by a scan device. Some (or all) of the final scan settings in a scan ticket may be default settings that a user does not modify when the user creates a scan job, which includes the scan ticket. Non-limiting examples of scan settings include contrast, resolution, color, scale, orientation, and simplex/duplex printing. 
         [0004]    For many users, selecting a scan ticket for a particular scan job is not easy. Many users do not understand how each setting would affect the final scan result. Even if a user finalizes the scan settings for scanning one type of document (e.g., text documents), if the user then desires to scan a photograph, then the user must learn a new set of scan settings for scanning the photograph in a desired manner. Typically, scanning a text document requires different settings (and thus a different scan ticket) than scanning a photograph. 
         [0005]    To compound the problem, in an enterprise environment where users may have access to multiple scanners, different scanners typically have different capabilities. For example, one scanner may have a higher resolution capability than other scanners. As another example, one scanner may be capable of scanning in color while other scanners only scan in black and white. Thus, scanning a document on one scanner may require a different set of scan settings than scanning the document on another scanner in order to achieve the same (or similar) desired outcome. 
       SUMMARY 
       [0006]    Accordingly, scan ticket templates are introduced to assist a user in choosing proper scan settings for different types of documents on different scan devices. According to an embodiment of the invention, a scan device comprises a scan module and a scan ticket templates manager. The scan module is configured to implement a Web Services (WS) scan specification and cause an electronic version of a printed document to be generated at the scan device. The scan ticket templates manager is configured to manage scan ticket template data that corresponds to a plurality of scan ticket templates. Each of the plurality of scan ticket templates corresponds to a different set of default settings that are used by the scan device to indicate how the scan device is to scan a printed document. Also, each of two or more of the plurality of scan ticket templates corresponds to a different document type. 
         [0007]    The scan module is further configured to (a) receive, from a client device via a network, a request for at least a portion of the scan ticket template data and (b) in response to the request, send the request to the scan ticket templates manager. 
         [0008]    The scan ticket templates manager is further configured to, in response to the request: (a) retrieve a portion of the scan ticket template data, wherein the portion corresponds to one or more scan ticket templates of the plurality, and (b) send the portion to the scan module. The scan module is further configured to send to the portion to the client device. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    The present invention is illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings and in which like reference numerals refer to similar elements and in which: 
           [0010]      FIG. 1  is a block diagram that depicts an example scan system architecture, according to an embodiment of the invention; 
           [0011]      FIG. 2  is a block diagram that depicts various example modules that reside on a scan device, according to an embodiment of the invention; 
           [0012]      FIG. 3  is a sequence diagram that depicts a set of example communications for a client device obtaining a plurality of scan ticket templates that are maintained by a scan device, according to an embodiment of the invention; 
           [0013]      FIG. 4  is a flow diagram that depicts how a client request for scan ticket template data may be processed, according to an embodiment of the invention; 
           [0014]      FIG. 5  depicts an example scan ticket template, of a particular document type, that is sent to a client in response to the client&#39;s request for scan ticket template data, according to an embodiment of the invention; and 
           [0015]      FIG. 6  is a block diagram that illustrates a computer system upon which an embodiment of the invention may be implemented. 
       
    
    
     DETAILED DESCRIPTION 
       [0016]    In the following description, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, that the present invention may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form in order to avoid unnecessarily obscuring the present invention. 
       General Overview  
       [0017]    Techniques are provided herein for assisting a user in creating a scan ticket. Users are assisting in creating scan tickets for different document types and/or purposes (e.g., fast scan versus high quality scan), even for different scan devices. A scan device provides multiple scan ticket templates that are based on the scan device&#39;s capabilities. A particular scan ticket template may be for the purpose of scanning, e.g., a text document, a photograph, or a postcard. If the scan device is Web Services (WS-) enabled, then the scan specification is extended to support the retrieval (and, optionally, creation and update) of multiple scan ticket templates. With the scan template extension, clients can retrieve multiple scan ticket templates from a scan device or retrieve a specific scan ticket template. The user interface on the client device can list and/or display the scan ticket template(s) accordingly. After a user selects a particular scan ticket template, the user creates a scan job using the selected template or creates a scan ticket based on the selected template. 
         [0018]    Approaches described herein may take advantage of the fact that a particular scan device “knows” its capabilities better than a typical user knows the scan device&#39;s capabilities. As a result, the scan ticket templates maintained by a scan device may be tailored (e.g., “out of the box”) depending on the capabilities of the scan device and the specific document type (e.g., text documents or photographs) and/or specific scan purpose (e.g., high quality scan or low quality scan). Therefore, rather than providing a single set of default scan settings to a client for all scan jobs, a scan device maintains multiple different scan ticket templates, one for each type of document and/or scan purpose. 
       Scan System Architecture  
       [0019]      FIG. 1  is a block diagram that depicts an example scan system architecture  100 , according to an embodiment of the invention. Scan system architecture  100  comprises clients  110 A-C, network  120 , and scan devices  130 A-B. 
         [0020]    Each of clients  110 A-C may be any client that is capable of requesting scan services from scan devices  130 A-B. Non-limiting examples of clients  110 A-C include personal computers, cell phones, and personal digital assistants (PDAs). Each of clients  110 A-C includes a client application that is configured to request multiple scan ticket templates or one or more specified scan ticket templates. 
         [0021]    A scan job may be initiated at a client device (e.g., client  110 A) or at a scan device (e.g., scan device  130 A). Embodiments of the invention are not limited to scan jobs being initiated at a particular device. 
         [0022]    Clients  110 A-C are communicatively coupled to scan devices  130 A-B via network  120 . Network  120  may be implemented by any medium or mechanism that provides for the exchange of data between clients  110 A-C and scan devices  130 A-B. Non-limiting examples of network  120  include one or more Local Area Networks (LANs), one or more Wide Area Networks (WANs), the Internet, or any combination thereof. 
       Scan Device  
       [0023]      FIG. 2  is a block diagram that depicts various example modules  210 - 230  that reside on a scan device, such as scan device  130 A, according to an embodiment of the invention. Each of modules  210 - 230  may be implemented in computer software, computer hardware, or any combination of computer software and computer hardware. 
         [0024]    Scan device  130 A includes: a scanning module  210 , a scan templates handler module (ST handler)  220 , a scan templates manager module (ST manager)  230 , and a scan templates repository (ST repository)  240 . 
         [0025]    Scanning module  210  comprises one or more modules and provides a scan service. Scanning module  210  implements a Web Services (WS) scan service specification that is standardized by a Web Services standardizing body. Web services are described in more detail below. 
         [0026]    Scanning module  210  is configured to (a) receive, from a client device, a scan job that includes a scan ticket and (b) scan a document according to the settings indicated in the scan ticket. Scanning a document comprises causing an electronic version of the document to be generated according to the settings indicated (or specified) in a scan ticket. A document is any printed material that is capable of being scanned by a scan device. Non-limiting examples of documents include text documents, pictures, photographs, brochures, postcards, and identification cards. 
         [0027]    ST repository  240  stores scan ticket template data. In an alternative embodiment, ST repository  240  resides on a device that is separate from scan device  130 A and may be accessed over network  120  or another network. ST repository  240  may be a database or a file. Scan ticket template data may be stored in a variety of data formats, depending upon a particular limitation. Example formats include, without limitation, XML, HTML, and plain text. 
         [0028]    The scan ticket template data corresponds to a plurality of scan ticket templates. Each of the plurality of scan ticket templates corresponds to a different set of default scan settings that are used by the scan device to indicate how the scan device is to scan a document. Also, each of two scan ticket templates corresponds to a different document type. 
         [0029]    The scan ticket template data (or a portion thereof) may be stored on scan device  130 A before the time of sale of scan device  130 A, initially created by an administrator of scan device  130 A, and/or downloaded onto scan device  130 A from a remote site. 
         [0030]    ST handler  220  interfaces with scanning module  210  and ST manager  230  by parsing a scan ticket templates request from scanning module  210 , calling ST manager  230  for scan ticket template data, and returning the scan ticket template data to scanning module  210 . In an embodiment, ST handler  220  also serializes the scan ticket template information, received from ST manager  230 , in a defined format and sends the serialized information to scanning module  210 . 
         [0031]    ST manager  230  manages ST repository  240 . In addition to retrieving scan ticket template data from ST repository  240 , ST manager  230  is configured to create and/or update the scan ticket template data. In an embodiment, an administrator or end-user creates and updates scan ticket template data in ST repository  240  via a user interface to ST manager  230 . 
         [0032]    ST manager  230  uses location data to access the scan ticket template data in ST repository  240 . Table 1 is an example of location data that ST manager  230  accesses in response to request for scan ticket template data: 
         [0000]    
       
         
               
               
               
             
           
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                 Template Name 
                 Location 
               
               
                   
                   
               
             
             
               
                   
                 Photo 4X4 
                 Loc1 
               
               
                   
                 Fast Scan 
                 Loc2 
               
               
                   
                 General everyday scan 
                 Loc3 
               
               
                   
                 Text 
                 Loc4 
               
               
                   
                 Passport 
                 Loc5 
               
               
                   
                   
               
             
          
         
       
     
         [0033]    If all the scan ticket templates are stored in the same file (or table), then the location data in the “Location” column may indicate where in a particular file (or table) the corresponding scan ticket template is located. If the scan ticket templates are stored in different files (or tables), then the location data may indicate the name of the files (or tables) in which the corresponding scan ticket template is stored. Embodiments of the invention are not limited to how the scan ticket template data is stored. 
         [0034]    In an embodiment, ST manager  230  is configured to modify (or create a separate copy of) one or more scan ticket templates in response a change in the capabilities of scan device  130 A. For example, in response to the depletion of color ink, ST manager  230  creates a copy of each scan ticket template whose color/gray scale setting indicates “color” and changes the setting to “gray scale.” Then, in response to scan ticket template data requests, ST manager  230  may retrieve, depending on the specific request, one or more scan ticket templates copies that ST manager  230  created based on the changed capabilities of scan device  130 A. When a “lost” capability is restored, then ST manager  230  may remove the corresponding scan ticket template copies or store them for further use if the capability is changed in the future. 
         [0035]    In a related embodiment, the functionality of ST handler  220  is incorporated into ST manager  230  or vice versa, in which case there is only one ST module instead of two. 
       MFP 
       [0036]    A scan device, such as scan device  130 A, may be a multi-function peripheral (MFP). A scan device that is an MFP is a device that provides one or more services in addition to a scan service, such as a print service, a fax service, a copy service, and/or an archive service. Thus, if a scan device is an MFP that also includes a print service, then the MFP includes a printing module that is configured to process print data and cause a printed version of an electronic document reflected in the print data to be printed on a tangible medium, such as paper. Like scanning module  210 , the printing module may be implemented as computer hardware, compute software, or any combination of computer hardware and computer software. 
       Web Services  
       [0037]    The World Wide Web Consortium (“W3C”) is an international consortium that develops standards for the World Wide Web. The W3C defines a “web service” as a software system that is designed to support interoperable machine-to-machine interaction over a network. This definition encompasses many different systems, but in common usage, the term refers to those services that use Simple Object Access Protocol (SOAP)-formatted Extensible Markup Language (“XML”) envelopes and that have their interfaces described using Web Services Description Language (“WSDL”). Web services allow devices and applications to communicate with each other over one or more networks without the intervention of any human being, while using the same suite of protocols (e.g., Hypertext Transfer Protocol (“HTTP”)) that a human being would use to communicate with such devices and applications over one or more networks. 
         [0038]    The specifications that define web services are intentionally modular, and, as a result, there is no one document that defines all web services. Instead, there are a few core specifications that are supplemented by other specifications as the circumstances and choice of technology dictate. Common core specifications are SOAP, WSDL, WS-Discovery, WS-MetadataExchange, WS-Addressing, and WS-Security. Different specifications address different tasks and functions. 
         [0039]    SOAP is an XML-based, extensible message envelope format, with bindings to underlying protocols (e.g., HTTP and Simple Mail Transfer Protocol (“SMTP”)). Using XML, SOAP defines how messages should be formatted, so that those messages are formatted in such a way that the recipients of those messages (devices and applications) can understand those messages. SOAP can be used to perform remote procedure calls, for example. 
         [0040]    WSDL is an XML format that allows web service interfaces to be described along with the details of those interfaces&#39; bindings to specific protocols. WSDL is typically used to generate server and client code, and for configuration. 
         [0041]    In an embodiment, scanning module  210  implements the Devices Profile for Web Services (DPWS). DPWS may be a part of the WS scan specification that scanning module  210  implements. DPWS defines a minimal set of implementation constraints to enable secure Web Service messaging, discovery, description, and eventing on devices. The DPWS specification defines an architecture in which devices run two types of services: hosting services and hosted services. Hosting services are directly associated to a device and play an important part in the device discovery process. Hosted services are mostly functional and depend on their hosting device for discovery. DPWS builds on the following core Web Services standards: WSDL 1.1, XML Schema, SOAP 1.2, WS-Addressing, and further comprises WS-MetadataExchange, WS-Transfer, WS-Policy, WS-Security, WS-Discovery and WS-Eventing. The latest DPWS specification (published in February, 2006) is incorporated herein by reference as if fully disclosed herein. 
         [0042]    In a related embodiment, the WS scan specification that scanning module  210  implements is standardized by W3C or another Web Services standardizing body, such as the Organization for the Advancement of Structured Information Standards (OASIS). Additionally or alternatively, the WS scan specification may be drafted and promoted by a certain company, such as Microsoft, whose operating system has built-in support for the specification. As a consequence, many scanner vendors may adopt the WS scan specification to better communicate with the company&#39;s scan client. The WS scan specification is extended to support multiple scan ticket templates. 
         [0043]    Additionally, a client device (e.g., client  110 A) may implements one or more WS specifications, one of which is extended to support the requesting of multiple scan ticket templates or of one or more specific templates. 
       Communication Between a Client and a Scan Device  
       [0044]      FIG. 3  is a sequence diagram that depicts a set of example communications for a client device obtaining a plurality of scan ticket templates that are maintained by a scan device, according to an embodiment of the invention.  FIG. 3  depicts communication between four entities: client  110 A, scanning module  210 , ST handler  220 , and ST manager  230 . 
         [0045]    At step  1 , scanning module  210  sends a HELLO message, which message is received by client  110 A. The HELLO message may be a broadcast message or a multi-cast message that is sent into network  120 . The message may conform to the WS-Discovery protocol, as defined by the WS-Discovery specification. 
         [0046]    At step  2 , in response to the HELLO message and as part of the WS-Discovery protocol, client  110 A requests and receives metadata of scanning module  210 . 
         [0047]    At step  3 , client  110 A requests and receives a scanner description of scanning module  210 . Scanner description includes information such as model, manufacture, and the service endpoint, which client  110 A will use to communicate with the scan service for further operations, such as retrieving templates and creating scan jobs. 
         [0048]    At step  4 , client  110 A requests, from scanning module  210 , multiple scan ticket templates that are maintained by the scan device. In response to the request (at step  5 ), scanning module  210  forwards the request to ST handler  220 . In response (at step  6 ), ST handler  220 , in turn, deserializes the request and then calls a “GetAndPackageTemplateInfo” API function of ST manager  230 . In response (at step  7 ), ST manager  230  retrieves a plurality of scan ticket templates from ST repository  240 . 
         [0049]    At step  8 , ST manager  230  sends the plurality of scan ticket templates to ST handler  220 . In response (at step  9 ), ST handler  220  serializes the template data and then forwards the serialized template data to scanning module  210 . “Serialization” refers to the generation of a SOAP message that will include the template data. 
         [0050]    At step  10 , scanning module  210  sends the packaged data to client  110 A. Client  110 A displays, to a user, a list that identifies each of the plurality of scan ticket templates. 
         [0051]    At step  11 , in response to the user instructing client  110 A to select one of the plurality of scan ticket templates, client  110 A creates a scan job using the selected template and sends the scan job to scanning module  210 . The user may or may not change the default settings in the selected scan ticket template. Thus, the user may first modify a selected template and then create a scan job based on that modified template. 
         [0052]    In an embodiment, client  110 A stores the plurality of scan ticket templates that are received from scanning module  210  for future use. 
       Communication Between a Client and a Device  
       [0053]      FIG. 4  is a flow diagram that depicts how a client request for scan ticket template data may be processed, according to an embodiment of the invention.  FIG. 4  depicts three processes on a scan device (e.g., scan device  130 A): scanning module  210 , ST handler  220 , and ST manager  230 . 
         [0054]    At step  402 , scanning module  210  receives, from a client application executing on a client device (e.g., client  110 A) a request at least a portion of scan ticket template data that scanning module  210  maintains. The request may be a SOAP request, i.e., that conforms to the SOAP protocol. The portion corresponds to one or more scan ticket templates. Specifically, the request may indicate that all scan ticket templates maintained by the scan device are requested without specifying any particular scan ticket template. Alternatively, the request may specify one or more particular scan ticket templates that are maintained by the scan device. Scanning module  210  also forwards the request to ST handler  220 . 
         [0055]    At step  404 , ST handler  220  receives the request from scanning module  210 . At step  406 , ST handler  220  analyzes (or deserializes) the request to determine which template(s) is/are requested. 
         [0056]    At step  408 , ST handler  220  determines whether the request is valid. If the request is for one or more particular templates, then this determination may entail determining whether each particular template is supported or stored on the scan device. If the particular template is not supported by the scan device, then the request is invalid. 
         [0057]    If the request is valid, then (at step  410 ) ST handler  220  calls an API of ST manager  230  and the process proceeds to step  414 . If the request is invalid, then (at step  412 ) ST handler  220  generates a message that indicates that the request is invalid and sends to the request to scanning module  210 . 
         [0058]    At step  414 , ST manager  230  is notified of the request via the API call invoked by ST handler  220  in step  410 . 
         [0059]    At step  416 , ST manager  230  retrieves the requested scan ticket template data from a template repository, such as ST repository  240 . 
         [0060]    At step  418 , ST manager  230  returns the requested scan ticket template data to ST handler  220 . 
         [0061]    At step  420 , ST handler  220  serializes the requested scan ticket template data received from ST manager  230 . 
         [0062]    At step  422 , ST handler  220  returns the serialized results to scanning module  210 . 
         [0063]    At step  424 , scanning module  210  processes the serialized results and returns the results to the client. 
       Scan Ticket Template  
       [0064]    Each scan ticket template that a scan device maintains corresponds to a different set of default scan settings. The scan settings indicated in a finalized scan ticket dictate how a scanner scans a document. Some of the scan settings may not be adjustable. For example, if a scan device is not capable of scanning documents in color, then each of the templates maintained on the scan device indicate that the color is “gray scale” or “black/white.” What client can see for each scan setting is based on the capabilities of the scan device. Thus, if a scan device has no color capability, then the user will not see color in the selection list. Therefore, the user cannot select it. 
         [0065]      FIG. 5  depicts an example scan ticket template  500 , of a particular document type, that is sent to a client in response to the client&#39;s request for scan ticket template data, according to an embodiment of the invention. According to this example, Template  500  is for documents of type “PHOTO” (i.e., photographs). Also, template  500  is formatted in XML. The outer tag of template  500  is “ScanTemplate,” which has two “children” tags: “ScanTemplateName” and “ScanTicket.” The “ScanTicket” template has a single child tag entitled “DocumentParameters,” which refers to the default scan settings for documents of type “PHOTO.” Within the “DocumentParameters” tag, multiple scan settings are indicated and defined, such as the format, the number of images to transfer, the input source, exposure (which includes contrast, brightness, and sharpness), scaling, rotation, color, and resolution. 
       Implementation Mechanisms  
       [0066]      FIG. 6  is a block diagram that illustrates a computer system  600  upon which an embodiment of the invention may be implemented. Computer system  600  includes a bus  602  or other communication mechanism for communicating information, and a processor  604  coupled with bus  602  for processing information. Computer system  600  also includes a main memory  606 , such as a random access memory (RAM) or other dynamic storage device, coupled to bus  602  for storing information and instructions to be executed by processor  604 . Main memory  606  also may be used for storing temporary variables or other intermediate information during execution of instructions to be executed by processor  604 . Computer system  600  further includes a read only memory (ROM)  608  or other static storage device coupled to bus  602  for storing static information and instructions for processor  604 . A storage device  610 , such as a magnetic disk or optical disk, is provided and coupled to bus  602  for storing information and instructions. 
         [0067]    Computer system  600  may be coupled via bus  602  to a display  612 , such as a cathode ray tube (CRT), for displaying information to a computer user. An input device  614 , including alphanumeric and other keys, is coupled to bus  602  for communicating information and command selections to processor  604 . Another type of user input device is cursor control  616 , such as a mouse, a trackball, or cursor direction keys for communicating direction information and command selections to processor  604  and for controlling cursor movement on display  612 . This input device typically has two degrees of freedom in two axes, a first axis (e.g., x) and a second axis (e.g., y), that allows the device to specify positions in a plane. 
         [0068]    The invention is related to the use of computer system  600  for implementing the techniques described herein. According to one embodiment of the invention, those techniques are performed by computer system  600  in response to processor  604  executing one or more sequences of one or more instructions contained in main memory  606 . Such instructions may be read into main memory  606  from another machine-readable medium, such as storage device  610 . Execution of the sequences of instructions contained in main memory  606  causes processor  604  to perform the process steps described herein. In alternative embodiments, hard-wired circuitry may be used in place of or in combination with software instructions to implement the invention. Thus, embodiments of the invention are not limited to any specific combination of hardware circuitry and software. 
         [0069]    The term “machine-readable medium” as used herein refers to any medium that participates in providing data that causes a machine to operation in a specific fashion. In an embodiment implemented using computer system  600 , various machine-readable media are involved, for example, in providing instructions to processor  604  for execution. Such a medium may take many forms, including but not limited to storage media and transmission media. Storage media includes both non-volatile media and volatile media. Non-volatile media includes, for example, optical or magnetic disks, such as storage device  610 . Volatile media includes dynamic memory, such as main memory  606 . Transmission media includes coaxial cables, copper wire and fiber optics, including the wires that comprise bus  602 . Transmission media can also take the form of acoustic or light waves, such as those generated during radio-wave and infra-red data communications. All such media must be tangible to enable the instructions carried by the media to be detected by a physical mechanism that reads the instructions into a machine. 
         [0070]    Common forms of machine-readable media include, for example, a floppy disk, a flexible disk, hard disk, magnetic tape, or any other magnetic medium, a CD-ROM, any other optical medium, punchcards, papertape, any other physical medium with patterns of holes, a RAM, a PROM, and EPROM, a FLASH-EPROM, any other memory chip or cartridge, a carrier wave as described hereinafter, or any other medium from which a computer can read. 
         [0071]    Various forms of machine-readable media may be involved in carrying one or more sequences of one or more instructions to processor  604  for execution. For example, the instructions may initially be carried on a magnetic disk of a remote computer. The remote computer can load the instructions into its dynamic memory and send the instructions over a telephone line using a modem. A modem local to computer system  600  can receive the data on the telephone line and use an infra-red transmitter to convert the data to an infra-red signal. An infra-red detector can receive the data carried in the infra-red signal and appropriate circuitry can place the data on bus  602 . Bus  602  carries the data to main memory  606 , from which processor  604  retrieves and executes the instructions. The instructions received by main memory  606  may optionally be stored on storage device  610  either before or after execution by processor  604 . 
         [0072]    Computer system  600  also includes a communication interface  618  coupled to bus  602 . Communication interface  618  provides a two-way data communication coupling to a network link  620  that is connected to a local network  622 . For example, communication interface  618  may be an integrated services digital network (ISDN) card or a modem to provide a data communication connection to a corresponding type of telephone line. As another example, communication interface  618  may be a local area network (LAN) card to provide a data communication connection to a compatible LAN. Wireless links may also be implemented. In any such implementation, communication interface  618  sends and receives electrical, electromagnetic or optical signals that carry digital data streams representing various types of information. 
         [0073]    Network link  620  typically provides data communication through one or more networks to other data devices. For example, network link  620  may provide a connection through local network  622  to a host computer  624  or to data equipment operated by an Internet Service Provider (ISP)  626 . ISP  626  in turn provides data communication services through the world wide packet data communication network now commonly referred to as the “Internet”  628 . Local network  622  and Internet  628  both use electrical, electromagnetic or optical signals that carry digital data streams. The signals through the various networks and the signals on network link  620  and through communication interface  618 , which carry the digital data to and from computer system  600 , are exemplary forms of carrier waves transporting the information. 
         [0074]    Computer system  600  can send messages and receive data, including program code, through the network(s), network link  620  and communication interface  618 . In the Internet example, a server  630  might transmit a requested code for an application program through Internet  628 , ISP  626 , local network  622  and communication interface  618 . 
         [0075]    The received code may be executed by processor  604  as it is received, and/or stored in storage device  610 , or other non-volatile storage for later execution. In this manner, computer system  600  may obtain application code in the form of a carrier wave. 
         [0076]    In the foregoing specification, embodiments of the invention have been described with reference to numerous specific details that may vary from implementation to implementation. Thus, the sole and exclusive indicator of what is the invention, and is intended by the applicants to be the invention, is the set of claims that issue from this application, in the specific form in which such claims issue, including any subsequent correction. Any definitions expressly set forth herein for terms contained in such claims shall govern the meaning of such terms as used in the claims. Hence, no limitation, element, property, feature, advantage or attribute that is not expressly recited in a claim should limit the scope of such claim in any way. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense.