Abstract:
A client state object, such as a “cookie,” allows a server to save client state information on the client. This information is returned when the client requests information from the server. A server includes two identifiers—a primary name and an alternate name. Web pages on the server are modified so that links to server resources, such as files, that need client state information reference the primary name, while other links that do not need client state information reference the alternate name. In this manner, it does not matter which directory on the server is used to store files and files can be intermingled with one another regardless of whether the individual files use client state information. A method is provided for modifying existing web pages based on whether server resources addressed by the hyperlinks use client state information.

Description:
BACKGROUND OF THE INVENTION 
   1. Technical Field 
   The present invention relates in general to a method and system for improving an Internet server&#39;s handling of client state objects. More particularly, the present invention relates to a system and method reducing the amount of unnecessary state object, or “cookie,” traffic between a client computer and the server computer. 
   2. Description of the Related Art 
   Some Internet web sites (i.e., servers) store client state information in a small text file, sometimes called a “cookie,” on the client&#39;s (i.e., user&#39;s) hard drive or in memory located on the client computer. Internet Browsers, such as Microsoft&#39;s Internet Explorer™ and Netscape&#39;s Navigator™, are often set up to allow the creation of these state objects. The user, however, can specify that a prompt be provided before a web site puts a state object on the user&#39;s hard disk or memory. In this manner, the user can choose to accept or reject state objects. The user can also configure the browser to prevent the acceptance of any state objects. 
   State objects are small data structures used by a web site to deliver data to a web client and store the data on the client&#39;s hard drive or memory. In certain circumstances, the client returns the information to the web site. Web sites can thus “remember” information about users to facilitate their preferences for a particular site. The web site may deliver one or more state objects to the client which are stored as flat files on the client&#39;s local hard drive or memory. 
   State objects contain information about the user and his or her preferences. For example, if the user inquires about a flight schedule at an airliner&#39;s Web site, the site might create a state object (i.e., a cookie) that contains the user&#39;s itinerary. Or it might only contain a record of which pages within the site the user visited, in order to help the site customize the view for the user during subsequent visits to the web site. 
   Only the information provided by the user or choices made by the user while visiting a Web site can be stored in a state object. For example, the web site cannot determine the user&#39;s e-mail name unless the user provides it. Allowing a Web site to create a state object, or cookie, on the client&#39;s computer does not give the web site, or any other web site, access to the rest of the client computer. In addition, only the site that created the state object is able to read it. 
   State objects are a general mechanism which server side connections (i.e., web sites) can use to both store and retrieve information on the client (i.e., user) side of the connection. The addition of a simple, persistent, client-side state significantly extends the capabilities of Web-based client/server applications. Web sites use state objects to simulate a continuous connection to the web site. This makes it more convenient for users by allowing them to visit pages within a site without having to reintroduce themselves with each mouse click. 
   HyperText Transfer Protocol (HTTP), is the underlying protocol used by the World Wide Web. HTTP defines how messages are formatted and transmitted, and what actions Web servers and browsers take in response to various commands. For example, when a user enters a URL (Uniform Resource Locator—the global address of documents and other resources on the World Wide Web) in a browser, an HTTP command is sent to the Web server directing it to fetch and transmit the requested Web page. The current HTTP protocol is “stateless,” meaning that the server does not store any information about a particular HTTP transaction; each connection between a client and a server is “fresh” and has no knowledge of any previous HTTP transactions. “State” information is information about a communication between a client and a server. In some cases it is useful to maintain state information about the user across multiple HTTP transactions. 
   When returning an HTTP object or other network information to a client, a server may include a piece of state information which is stored by the client. Included in that state object is a description of the range of URLs for which that state is valid. Any future requests made by the client which fall in that URL range will include a transmittal of the current value of the state object from the client back to the server. As described above, the state object is often called a “cookie,” for no compelling reason. 
   This simple mechanism provides a powerful tool which enables a host of applications to be written for web-based environments. Shopping applications can store information about currently selected items, for fee services can send back registration information and free the client from retyping a user-id on subsequent connections, and web sites can store per-user preferences on the client computer. These preferences can be automatically supplied by the client computer when the client subsequently connects to the server. 
   A cookie is introduced to the client by including a “Set-Cookie” header as part of an HTTP response; often this will be generated by a CGI script. CGI stands for “Common Gateway Interface,” a specification for transferring information between a World Wide Web server and a CGI program. A CGI program is any program designed to accept and return data that conforms to the CGI specification. The program,.could be written in any programming language, including C, Perl, Java, or Visual Basic. 
   Syntax of the Set-Cookie HTTP Response Header 
   This is the format a CGI script would use to add to the HTTP headers a new piece of data which is to be stored by the client for later retrieval. 
   Set-Cookie: NAME=VALUE; expires=DATE; 
   path=PATH; domain=DOMAIN_NAME; secure 
   Multiple Set-Cookie headers can be issued in a single server response. 
   NAME=VALUE 
   This string is a sequence of characters excluding semi-colon, comma and white space. This is the only required attribute on the Set-Cookie header. 
   expires=DATE 
   The expires attribute specifies a date string that defines the valid life time of that cookie. Once the expiration date has been reached, the cookie will no longer be stored or given out. Expires is an optional attribute. If not specified, the cookie will expire when the user&#39;s session ends. 
   The expires header lets the client know when it is safe to purge the mapping but the client is not required to do so. A client may also delete a cookie before its expiration date arrives, for example if the number of cookies exceeds its internal limits. 
   domain=DOMAIN NAME 
   When searching the cookie list for valid cookies, a comparison of the domain attributes of the cookie is made with the Internet domain name of the host from which the URL will be fetched. If there is a tail match, then the cookie will go through “path matching” to see if it should be sent (see description of “path,” below). “Tail matching” means that the domain attribute is matched against the tail of the fully qualified domain name of the host. A domain attribute of “acme.com” would therefore match host names “anvil.acme.com” as well as “shipping.crate.acme.com”. The default value of domain is the host name of the server which generated the cookie response. 
   Only hosts within the specified domain can set a cookie for a domain. Domains that store cookies have at least two (2) or three (3) periods in them to prevent domains of the form “.com”, “.edu”, and “va.us” from storing overly-broad cookies. Any domain that falls within one of the special top level domains (e.g., “.COM”, “.EDU”, “.NET”, “.ORG”, “.GOV”, “.MIL”, and “.INT”) requires at least two periods. Any other domain requires at least three periods. 
   path=PATH 
   The path attribute is used to specify the subset of URLs in a domain for which the cookie is valid. If a cookie has already passed domain matching, then path matching takes place wherein the pathname component of the URL is compared with the path attribute. If there is a prefix match, the cookie is considered valid and is sent along with the URL request. The path “/foo” would match “/foobar” and “/foo/bar.html”. The path “/” is the most general path and matches any path within the domain. 
   If the path is not specified, it as assumed to be the same path as the document being described by the header which contains the cookie. Setting the path to a higher-level value does not override other more specific path mappings. If there are multiple matches for a given cookie name, but with separate paths, all the matching cookies will be sent (see examples below). Instances of the same path and name will overwrite each other, with the latest instance taking precedence. Instances of the same path but different names will add additional mappings. When sending cookies to a server, all cookies with a more specific path mapping should be sent before cookies with less specific path mappings. For example, a cookie “name 1 =foo” with a path mapping of “/” should be sent after a cookie “name 1 =foo 2 ” with a path mapping of “/bar” if they are both to be sent. 
   secure 
   If a cookie is marked secure, it will only be transmitted if the communications channel with the host is a secure one. Currently this means that secure cookies will only be sent to HTTPS (HTTP over SSL) servers. If secure is not specified, a cookie is considered safe to be sent in the clear over unsecured channels. 
   Syntax of the Cookie HTTP Request Header 
   When requesting a URL from an HTTP server, the browser will match the URL against all cookies and if any of them match, a line containing the name/value pairs of all matching cookies will be included in the HTTP request. Here is the format of that line:
         Cookie: NAME 1 =OPAQUE_STRING 1 ; NAME 2 =OPAQUE 13  STRING 2  . . .       

   There are limitations on the number of cookies that a client can store at any one time. 
   If a CGI script wishes to delete a cookie, it can do so by returning a cookie with the same name, and an expires time which is in the past. The path and name should match exactly in order for the expiring cookie to replace the valid cookie. This requirement makes it difficult for anyone but the originator of a cookie to delete a cookie. 
   When caching HTTP, as a proxy server might do, the Set-cookie response header should never be cached. If a proxy server receives a response which contains a Set-cookie header, it should propagate the Set-cookie header to the client, regardless of whether the response was 304 (Not Modified) or 200 (OK). Similarly, if a client request contains a Cookie: header, it should be forwarded through a proxy, even if the conditional If-modified-since request is being made. 
   EXAMPLES 
   Below are sample exchanges which illustrate the use of cookies: 
   First Example Transaction Sequence 
   
       
       1. Client requests a document, and receives in the response:
       Set-Cookie: CUSTOMER=WILE_E_COYOTE; path=/; expires=Wednesday, 09-Nov-99 23:12:40 GMT   
     
       2. When client requests a URL in path g/” on this server, it sends:
       Cookie: CUSTOMER=WILE —E _COYOTE   
     
       3. Client requests a document, and receives in the response:
       Set-Cookie: PART_NUMBER=ROCKET_LAUNCHER — 0001; path=/   
     
       4. When client requests a URL in path “/” on this server, it sends:
       Cookie: CUSTOMER=WILE_E_COYOTE; PART_NUMBER=ROCKET_LAUNCHER — 0001   
     
       5. Client receives:
       Set-Cookie: SHIPPING=FEDEX; path=/foo   
     
       6. When client requests a URL in path “/” on this server, it sends:
       Cookie: CUSTOMER=WILE_E_COYOTE; PART_NUMBER=ROCKET_LAUNCHER — 0001   
     
       7. When client requests a URL in path “/foo” on this server, it sends:
       Cookie: CUSTOMER=WILE_E_COYOTE; PART_NUMBER=ROCKET_LAUNCHER — 0001; SHIPPING=FEDEX   
     
     
  
   Second Example Transaction Sequence 
   (Assume all mappings from above have been cleared.) 
   
       
       1. Client receives:
       Set-Cookie: PART_NUMBER=ROCKET_LAUNCHER — 0001; path=/   
     
       2. When client requests a URL in path “/” on this server, it sends:
       Cookie: PART_NUMBER=ROCKET_LAUNCHER — 0001   
     
       3. Client receives:
       Set-Cookie: PART_NUMBER=RIDING_ROCKET — 0023; path=/ammo   
     
       4. When client requests a URL in path “/ammo” on this server, it sends:
       Cookie: PART_NUMBER=RIDING_ROCKET — 0023; PART_NUMBER=ROCKET_LAUNCHER — 0001   
     
     
  
   NOTE: There are two name/value pairs named “PART_NUMBER” due to the inheritance of the “/” mapping in addition to the “/ammo” mapping. 
   As illustrated above, a client computer has no way of determining whether a server actually needs a state object, such as a cookie. The browser, therefore, sends state object information to the server so long as the domain and path information matches. Because the current HTTP protocol is stateless, the state object must be included in all requests to the server regardless of whether the server needs the information. One challenge, therefore, in communicating state information is determining when a server actually needs the information. 
   When a client requests a file from a server, it contacts the server using an address of the file on the server. The address the client enters includes (1) the protocol to use (i.e., HTTP), (2) the server name (e.g., “acme.com”), and (3) the file name (or resource name) of the file being requested (e.g., “main.htm”). The browser communicates with a name server to translate the server name (e.g., www.acme.com) into an IP Address, which it uses to connect to that server machine. The browser then forms a connection to the Web server at that IP address on port  80 . Following the HTTP protocol, the browser sends a GET request to the server, asking for the file “http://www.acme.com/main.htm”. At this point, any matching state information stored on the client (i.e. cookies) are sent to the server. The server then sends the file (i.e. the HTML text corresponding to main.htm) back to the browser. The server may also include state information in its response that is stored on the client. In the case of an HTML file, the browser reads the HTML tags and formats the page on the client&#39;s screen. 
   This process of the client making GET requests and the server responding with data often occurs many times. Every time the user clicks on a hyperlink, the client issues a GET request and the server responds. Including state information with each GET request and response adds to the amount of data that are transmitted and processed by both the client and the server. Often, the state information is sent even though it is not needed for a particular GET request. 
   As discussed above, path mechanism can be used to more particularly indicate which location within a server corresponds with the state object. Unfortunately, many server web applications are not structured so that they can readily use the path mechanism. For example, in many web servers&#39; directory structures content that needs the state object is intermingled with content that does not need the state object. Another challenge is changing web pages to reduce the amount of state object information being transmitted without overly disrupting the content and organization of the server. 
   What is needed, therefore, is a way to reduce the amount of state object information transmissions between a client and server. Furthermore, what is needed is a way to reduce such transmissions by making minor changes to the web server that do not overly disrupt the content and organization of the server. 
   SUMMARY 
   It has been discovered that traffic between a server and a client can be improved by reducing the amount of client state information and server “set cookie” requests sent between the machines. The server resides in a domain and has two names that address the server. A “name alias” refers to two different names within the same domain (e.g., x.ibm.com and y.ibm.com). Another type of alternate name that can be used is a “domain alias” which refers to a registered name and a registered alias name (e.g., ibm.com and ibm_alias.com) that map to the same server. An “alternate name” can be either a name alias or a domain alias. Web pages served by the server can contain a variety of links to other files located on the server. If a particular file needs to set client state information (i.e., a “SET COOKIE” instruction) or receive client state information from the client, one of the server names is used to send the SET COOKIE request. 
   On the other hand, if a particular file does not need to set or receive client state information, the other, or alternate, name is used to address the file. Because files using the alternate name do not set or receive client state information, efficiency in transmitting and processing these files is improved. 
   In addition, existing web pages can be more easily modified to take advantage of the transmission and processing efficiencies. An existing web page is analyzed to determine whether links (i.e., hyperlinks) reference files that need client state information. If the files do not need client state information, the hyperlink is modified to point to the alternate rather than the regular, or primary, name. When the client uses the modified web page and selects a hyperlink that has been modified to address the alternate name, no corresponding client state information (i.e., a cookie file) is found, thus eliminating the unnecessary transfer of client state information. 
   The foregoing is a summary and thus contains, by necessity, simplifications, generalizations, and omissions of detail; consequently, those skilled in the art will appreciate that the summary is illustrative only and is not intended to be in any way limiting. Other aspects, inventive features, and advantages of the present invention, as defined solely by the claims, will become apparent in the non-limiting detailed description set forth below. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention may be better understood, and its numerous objects, features, and advantages made apparent to those skilled in the art by referencing the accompanying drawings. The use of the same reference symbols in different drawings indicates similar or identical items. 
       FIG. 1  is a network diagram showing the interaction between a client and a server; 
       FIG. 2  is a block diagram showing requests and responses being processed by a server with two names; 
       FIG. 3  is a flowchart showing the modification of hyperlinks in an existing web page; 
       FIG. 4  is a flowchart showing requests sent to a server and responses received from the server wherein the requests and responses selectively use client state information; and 
       FIG. 5  is a block diagram of an information handling system capable of implementing the present invention. 
   

   DETAILED DESCRIPTION 
   The following is intended to provide a detailed description of an example of the invention and should not be taken to be limiting of the invention itself. Rather, any number of variations may fall within the scope of the invention which is defined in the claims following the description. 
     FIG. 1  shows a network diagram of the interaction between a client and a. server. Client browser  100  includes client display  104  for displaying formatted browser content to the user. When the browser receives content, such as a HyperText Markup Language (HTML) file, the coded file is used to format the display area, including such things as graphics, frames, and animated images. Client state object information  108  includes previously stored information regarding the client. In one embodiment, client state object information  108  is stored in flat files called “cookies.” Client browser  100  also includes network destination  112 . Network destination  112  identifies a resource connected to computer network  196 . One example of a computer network is the Internet. Network destination  112  includes user provided Uniform Resource Locators (URLs) entered as an “address” in client browser  100 . Network destination  112  can also be provided by the user selecting a hyperlink on a web page being displayed in client display  104  or by the user selecting a previously stored destination address, such as a bookmark, from a list of addresses stored on the client computer. 
   When network destination  112  is provided, browser  100  checks state object information  108  to determine whether client state information should be passed to the destination web server along with the request. Request  116  includes destination  120  and, if appropriate, state information data  124  that corresponds with destination  120 . Destination  120  includes a server address (i.e., ibm.com) and a resource, such as a filename, being requested (i.e., mainpage.htm). Request  116  is sent to computer network  196 . Computer network passes the request onto web server  140 . 
   In the example shown, web server  140  has been configured so that resources, such as files, that use client state information are addressed using the web server&#39;s primary name. A “name alias” refers to two different names within the same domain (e.g., x.ibm.com and y.ibm.com). Another type of alternate name that can be used is a “domain alias” which refers to a registered name and a registered alias name (e.g., ibm.com and ibm_alias.com) that map to the same server. An “alternate name” can be either a name alias or a domain alias. If there was state information corresponding with the address, request  156  is received by web server  140 . In the example shown, request  156  would occur when the client addressed the server&#39;s primary name rather than the server&#39;s alternate name. Request  156  includes both destination  160  and client state data  164 . Client state data  164  is processed by client state processing  168 . If client state processing  168  determines that new or updated state information should be stored on the client, client state processing includes new state data  152  in response  144 . Response  144  also includes display data  148  which is provided from web server file  172 . Response  144  is transmitted through computer network  196  to client browser  100 . Response  128  is received by the client from computer network  196 . Display data  132  is read and displayed to the user in client display  104 . Any state information (i.e. a “SET COOKIE” request), is read from state data  136  and included with state object information  108 . 
   In the example shown, if destination  120  in client&#39;s request  116  pointed to the web server&#39;s alternate name, rather than the web server&#39;s primary name, request  116  would not include state data  124  because this alternate name is used as a means of separating destinations using client state information (i.e., the web server&#39;s primary name) from a destination that does not use client state information (the alternate name). In this manner, an existing web server page can be modified so that any links on the page that do not use client state information address the web server&#39;s alternate name. When the alternate name is selected by the user (i.e., by selecting a particular hyperlink appearing on the server&#39;s web page), no state information will be found because the alternate name does not appear in state object information  108 . Request  116  will then only include destination  120 . Destination  120  will include the alternate name of web server  140  and the file name being requested from the web server. Request  116  (without state data  124 ) is transmitted through computer network  196  and request  184  is received at web server  140 . Request  184  includes destination  188 , but does not include any state information from the client. While it is theoretically possible for the web server to include a cookie in a response from the alternate name, the web page and server application have been structured so that this does not occur. Response  176  includes display data  180  included from web server file  192 . Response  176  is transmitted through computer network  196  and received at client browser  100 . However, this response does not include any state data requests, so an association is never made between the web server&#39;s alternate name and any state object information. 
   Note that whether client state information is included in a request or response is determined by network destination  112  being requested by the client. In this manner, the same web server file can be used in conjunction with client state information or without. In the example shown, if the file is addressed using the web server&#39;s primary name, then client state information may be included. However, if the file is addressed using the web server&#39;s alternate name, then client state information is not included. 
     FIG. 2  shows a block diagram of requests and responses being processed by a server with two names. Web page  200  appears on client&#39;s browser while the user is using the client computer system. In the example shown, web page  200  includes two hyperlinks. Hyperlink  230  includes the web server&#39;s primary name (“ibm.com”) as part of the destination, while hyperlink  260  includes the web server&#39;s alternate name (“ibm_alias.com”) as part of the destination. While the example shown uses a domain alias as the alternate name, in another implementation a name alias (such as the primary name being “x.ibm.com” and the alternate name being “y.ibm.com”) could be used. 
   When hyperlink  230  is selected, state information is possibly included in request  240  (state information is supplied if the web site was previously visited and state information was retained on the client computer). Request  240  is transmitted through computer network  205  and received by web server  210 . If web server  210  adds or modifies client state information, then the state information is included in return response  240 . The requested file, “registration.htm”  250 , is also included in response  240 . 
   Hyperlink  260 , on the other hand, addresses the web server&#39;s alternate name (“ibm_alias.com”). While an alternate name can map to client state information, the present invention identifies at least one alternate name that should not be used with client state information. In this fashion, changing a hyperlink on a web page to point to the alternate name, rather than the primary name, prevents client state information from being identified on the client. In addition, responses from the server to requests made to the server&#39;s alternate name should refrain from adding client state requests (i.e., “SET COOKIE”), in order to keep the alias name out of the client state information retained by the client. In this manner, transmission and processing efficiency can be improved on an existing web site simply by changing hyperlinks on the web page to point to the alternate, rather than the primary, name. A name server operating on network  205  translates the destination name into an IP address. Both the primary name and the alternate name map to the same IP address, or in other words, the same web server. 
   In the example shown, web page  200  includes hyperlink  260  which includes the alternate name as part of the destination. When the user selects hyperlink  260 , request  270  is transmitted to web server  210  through computer network  205 . The file included in hyperlink  260  is “about_us.htm”. In response to request  270 , web server  210  returns the contents of about_us.htm  280  in response  270 and refrains from including any requests to add any client state information. As shown, the files returned to the user are both stored in a common directory  220 , on the same nonvolatile storage device  215 , within the same physical web server  210 . 
     FIG. 3  shows a flowchart of the modification of hyperlinks in an existing web page. A web page may exist in which all the links address the server&#39;s primary name. If the server uses client state information, unnecessary transmissions of such information may take place, especially if the client state information has been associated with the domain name and not segregated to a particular file or directory. The existing web page is modified to avoid unnecessary transmissions of this state information between the client and the server. 
   Processing commences at  300  whereupon an alternate name is created for the web server (step  310 ). If the alternate name is a domain alias (e.g., ibm_alias.com), it is included in lists processed by name servers on the computer network, such as the Internet, so that both the domain alias and the primary name point to the same IP address. If a name alias is used, then one of the names is used as a primary name (i.e., x.ibm.com) and the other is used as the name alias (i.e., y.ibm.com) with both names designed to translate to the same IP address. 
   A first link is read from the web page (input  320 ). A determination is made as to whether the link uses client state information (decision  330 ). The decision may be manual with a programmer analyzing the hyperlink, automated so that only links to certain known files use client state information, or semi-automated with a program reading the hyperlink and prompting a programmer or other user as to whether the link uses client state information. If the link does not use client state information, decision  330  branches to “no” branch  335  and the hyperlink address is modified so that the destination name is the alternate name rather than the primary name (step  340 ). On the other hand, if the link does use client state information, decision  330  branches to “yes” branch  345  whereupon the link is left alone (step  350 ) because it already points to the primary name. In the case where the hyperlink address already points to the alternate name, such as when the logic shown in  FIG. 3  is performed multiple times, then the hyperlink address is checked to ensure that it addresses the primary name and, if it does not address the primary name, the destination is modified to address the primary, rather than the alternate, name. 
   A determination is made as to whether there are more hyperlinks on the web page to be analyzed (decision  360 ). If there are more hyperlinks, decision  360  branches to “yes” branch  365  which reads the next hyperlink information (input  370 ) and loops back to decision  330 . This looping continues until no more hyperlinks need to be analyzed, in which case decision  360  branches to “nox branch  380  and processing terminates at  390 . 
     FIG. 4  shows a flowchart of requests sent to a server and responses received from the server wherein the requests and responses selectively use client state information. 
   Client processing commences at  400  and server processing commences at  405 . The client requests data from a server (step  410 ). The request can be an address entered in a browser, a stored address in a bookmark file, or an address encoded in a hyperlink on a displayed web page. A determination is made whether the link points to an alternate name (decision  420 ). The actual decision made is whether any client state information corresponds with the destination address because the client computer is generally unable to ascertain whether an address is for a primary name or an alternate name. However, the present invention keeps alternate name responses from making client state requests, so if the destination address is an alternate name there will not be any corresponding client state information. If the destination does not include an alternate name (i.e., the destination is the primary name), then decision  420  branches to “no,” branch  425  whereupon any state information corresponding to the primary name is added to the request (step  430 ). On the other hand, if the link points to an alternate name, decision  420  branches to “yes” branch  435  and no state information is added to the request. 
   Request  445  is sent from the client (step  440 ) and received and processed by the server (step  450 ). If the destination address does not point to the server&#39;s alternate name, decision  460  branches to “no” branch  465  and any necessary client state updates are included with the response (step  470 ). On the other hand, if the destination address points to the server&#39;s alternate name, decision  460  branches to “yes” branch  475  and no client state requests are included in the response. Response  485  is sent by server (step  480 ) to the client whereupon the client receives and processes the response (step  490 ). A determination is made whether the client has more selections (decision  492 ). If the client has more selections, decision  492  branches to “yes” branch  496  which loops back to get the next request from the client. This looping continues until the client has no more requests, at which time decision  492  branches to “no” branch  498  and processing terminates at  499 . 
     FIG. 5  illustrates information handling system  501  which is a simplified example of a computer system capable of performing the server and client operations described herein. Computer system  501  includes processor  500  which is coupled to host bus  505 . A level two (L2) cache memory  510  is also coupled to the host bus  505 . Host-to-PCI bridge  515  is coupled to main memory  520 , includes cache memory and main memory control functions, and provides bus control to handle transfers among PCI bus  525 , processor  500 , L2 cache  510 , main memory  520 , and host bus  505 . PCI bus  525  provides an interface for a variety of devices including, for example, LAN card  530 . PCI-to-ISA bridge  535  provides bus control to handle transfers between PCI bus  525  and ISA bus  540 , universal serial bus (USB) functionality  545 , IDE device functionality  550 , power management functionality  555 , and can include other functional elements not shown, such as a real-time clock (RTC), DMA control, interrupt support, and system management bus support. Peripheral devices and input/output (I/O) devices can be attached to various interfaces  560  (e.g., parallel interface  562 , serial interface  564 , infrared (IR) interface  566 , keyboard interface  568 , mouse interface  570 , and fixed disk (HDD)  572 ) coupled to ISA bus  540 . Alternatively, many I/O devices can be accommodated by a super I/O controller (not shown) attached to ISA bus  540 . 
   BIOS  580  is coupled to ISA bus  540 , and incorporates the necessary processor executable code for a variety of low-level system functions and system boot functions. BIOS  580  can be stored in any computer readable medium, including magnetic storage media, optical storage media, flash memory, random access memory, read only memory, and communications media conveying signals encoding the instructions (e.g., signals from a network). In order to attach computer system  501  to another computer system to copy files over a network, LAN card  530  is coupled to PCI bus  525  and to PCI-to-ISA bridge  535 . Similarly, to connect computer system  501  to an ISP to connect to the Internet using a telephone line connection, modem  575  is connected to serial port  564  and PCI-to-ISA Bridge  535 . 
   While the computer system described in  FIG. 5  is capable of executing the invention described herein, this computer system is simply one example of a computer system. Those skilled in the art will appreciate that many other computer system designs are capable of performing the invention described herein. 
   One of the preferred implementations of the invention is an application, namely, a set of instructions (program code) in a code module which may, for example, be resident in the random access memory of the computer. Until required by the computer, the set of instructions may be stored in another computer memory, for example, on a hard disk drive, or in removable storage such as an optical disk (for eventual use in a CD ROM) or floppy disk (for eventual use in a floppy disk drive), or downloaded via the Internet or other computer network. Thus, the present invention may be implemented as a computer program product for use in a computer. In addition, although the various methods described are conveniently implemented in a general purpose computer selectively activated or reconfigured by software, one of ordinary skill in the art would also recognize that such methods may be carried out in hardware, in firmware, or in more specialized apparatus constructed to perform the required method steps. 
   While particular embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that, based upon the teachings herein, changes and modifications may be made without departing from this invention and its broader aspects and, therefore, the appended claims are to encompass within their scope all such changes and modifications as are within the true spirit and scope of this invention. Furthermore, it is to be understood that the invention is solely defined by the appended claims. It will be understood by those with skill in the art that if a specific number of an introduced claim element is intended, such intent will be explicitly recited in the claim, and in the absence of such recitation no such limitation is present. For a non-limiting example, as an aid to understanding, the following appended claims contain usage of the introductory phrases “at least one” and “one or more” to introduce claim elements. However, the use of such phrases should not be construed to imply that the introduction of a claim element by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim element to inventions containing only one such element, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an”; the same holds true for the use in the claims of definite articles.