Automatic retrieval of changed files by a network software agent

In a distributed computing system having a network of computers linked for accessing objects distributed among said computers, some of said computers executing object access software for providing client browsers for fetching said objects, a computer-implemented method of operating at least one of said computers for automatically notifying said client browsers when objects of interest are changed, said computer-implemented method comprising the steps of:

• a) accepting from each client browser a specification of an object of interest, said specification including a resource locator identifying one of said computers containing said object of interest;
• b) maintaining in memory a list of the client browsers interested in said object of interest;
• c) checking a cache memory for said object of interest, and when said cache memory does not contain said object of interest, obtaining said object of interest by transmitting said object of interest over said network from said one of said computers containing said object of interest to said cache memory, storing said object of interest in said cache memory, and modifying the resource locator for said object of interest to create a modified resource locator for said object of interest identifying said cache memory as a location for obtaining said object of interest;
• d) transmitting the modified resource locator for said object of interest from said cache memory to said each client browser, said each client browser thereafter using said modified locator for said object of interest to fetch said object of interest from said cache memory;
• e) detecting occurrence of change in said object of interest, and in response to detecting the occurrence of change in said object of interest, determining whether an update notification would then be desirable for each of the client browsers in the list of client browsers interested in said object of interest;
• and
• f) upon determining that an update notification would then be desirable for one of the client browsers in response to detecting the occurrence of change in said object of interest, notifying said one of the client browsers of the occurrence of change in said object of interest.

In a distributed computing system having a network of computers linked for accessing objects distributed among said computers, some of said computers executing object access software for providing client browsers for fetching said objects, said object access software using standard resource location protocols for specifying the objects to be fetched, a computer-implemented method of operating at least one of said computers for providing objects from a cache located close to a group of said client browsers, said computer-implemented method comprising the steps of:

• a) obtaining objects of interest to said group of client browsers by transmitting said objects of interest over said network to said cache from computers in said distributed computing system containing said objects of interest;
• and
• b) transmitting said objects of interest from said cache to said client browsers in said group of client browsers;
• wherein said client browsers are HTTP-compliant client browsers following an HTTP client-to-server data transmission protocol, and said method further includes modifying resource locators for said objects of interest to create modified resource locators identifying said cache as a location for obtaining said objects of interest.

In a distributed computing system having a network of computers linked for accessing objects distributed among said computers, some of said computers executing object access software for providing client browsers for fetching said objects, said object access software using standard resource location protocols for specifying the objects to be fetched, a computer-implemented method of operating at least one of said computers for providing objects from a cache located close to a group of said client browsers, said computer-implemented method comprising the steps of:

• a) obtaining objects of interest to said group of client browsers by having said objects of interest transmitted over said network to said cache from computers in said distributed computing system containing said objects of interest;
• and
• b) transmitting said objects of interest from said cache to said client browsers in said group of client browsers;
• wherein said method further includes:
• c) accepting from said client browsers specifications of objects of interest for which said client browsers desire notification of changes;
• d) detecting occurrence of changes in the objects of interest, and in response to detecting the occurrence of a change in an object of interest, determining whether an update notification would then be desirable for each client browser desiring notification of changes in the object of interest in which the occurrence of change is detected;
• and
• e) upon determining that an update notification would then be desirable for one of the client browsers, notifying said one of the client browsers of the occurrence of change in said one of said objects of interest.

A distributed computing system comprising a network of computers linked for accessing objects distributed among said computers. some of said computers executing object access software for providing client browsers for fetching said objects, said object access software using standard resource location protocols for specifying the objects to be fetched, wherein a plurality of said computers are distributed around the network and programmed to maintain in respective cache memories objects of interest to respective neighboring groups of said client browsers by fetching the objects of interest from various ones of said computers across said network and storing the objects of interest in the cache memories, and transmitting the objects of interest from the cache memories to the respective neighboring groups of said client browsers;

• further including means for employing performance, cost or quality statistics of resource accesses to select among alternative sources for the objects of interest stored in said cache memories;
• and
• wherein said cache memories are distributed at selected locations around said network, and said client browsers are selectively grouped to be serviced by said cache memories, in order to optimize expected value of an objective function in probability over a distribution of expected accesses of the objects of interest to the client browsers included in said groups of client browsers.

A distributed computing system comprising a network of computers linked for accessing objects distributed among said computers, some of said computers executing object access software for providing client browsers for fetching said objects, said object access software using standard resource location protocols for specifying the objects to be fetched, wherein a plurality of said computers are distributed around the network and programmed to maintain in respective cache memories objects of interest to respective neighboring groups of said client browsers by fetching the objects of interest from various ones of said computers across said network and storing the objects of interest in the cache memories, and transmitting the objects of interest from the cache memories to the respective neighboring groups of said client browsers;

• further including means for employing Performance, cost or quality statistics of resource accesses to select among alternative sources for the objects of interest stored in said cache memories;
• and
• means associated with one of said cache memories for determining, for each object of interest in said one of said cache memories and for each client browser serviced by said one of said cache memories and being interested in said each object of interest in said one of said cache memories, whether an update notification would be desirable at a specific point in time.

In a distributed computing system having a network of clients and servers, said clients sending resource requests to said servers, a computer-implemented method of using a resource manager in said distributed computing system for intermediating between said clients and servers, said method including the steps of:

• a) said resource manager intercepting said resource requests from said clients;
• b) said resource manager fetching objects from servers to satisfy said resource requests from said clients, said objects fetched from said servers having respective resource locators identifying the respective sources of the objects fetched from said clients;
• c) said resource manager modifying said resource locators to identify said resource manager as a source for the objects fetched from the servers to satisfy said resource requests from said clients;
• and
• d) said resource manager returning the fetched objects and modified resource locators to said clients.

In a distributed computing system having a network of computers linked for accessing objects distributed among said computers, some of said computers executing object access software for enabling interested parties to request access to said objects, a computer-implemented method of providing the interested parties with summary reports of how objects of interest have changed, said computer-implemented method comprising the steps of:

• a) accepting from said interested parties specifications of the objects of interest;
• b) maintaining in memory a list of the interested parties interested in each of the objects of interest;
• c) maintaining in memory a list of mechanisms for notifying the interested parties of changes in each of the objects of interest;
• d) detecting occurrence of changes in the objects of interest, and in response to detecting an occurrence of a change in an object of interest, recording information about the change in the object of interest;
• and
• e) using recorded information about changes in the object of interest that has changed, using the list of interested parties interested in the object that has changed, and using the list of mechanisms for notifying the interested parties of changes in the object of interest that has changed, to provide, to the interested parties interested in the object that has changed, a summary of changes in the object of interest that has changed, said summary of changes including changes occurring since a certain point in time.

In a distributed computing system having a network of computers linked for accessing objects distributed among said computers, some of said computers executing object access software enabling interested parties to request access to said objects, a computer-implemented method of operating at least one of said computers for automatically notifying said interested parties when objects of interest are changed, said computer-implemented method comprising the steps of:

• a) accepting from said interested parties specifications of the objects of interest;
• b) maintaining in memory a list of the interested parties interested in each of the objects of interest;
• c) maintaining in memory a list of mechanisms for notifying the interested parties of changes in each of the objects of interest;
• d) determining when an update notification would be desirable for each interested party in the list of interested parties;
• and
• e) when an update notification would be desirable for one of the interested parties interested in one of the objects of interest, using said list of mechanisms to notify said one of the interested parties of the occurrence of change in said one of the objects of interest.

In a distributed computing system having a network of computers linked for accessing objects distributed among said computers, some of said computers executing object access software for enabling interested parties to request access to said objects, a computer-implemented method of operating at least one of said computers for notifying a group of said interested parties when a change of significance is made to an object of interest to said group, said computer-implemented method comprising the steps of:

• a) accepting from said interested parties specifications of the objects of interest;
• b) maintaining in memory a list of the interested parties interested in each of the objects of interest;
• c) determining, for each object of interest, whether a change of significance has been made to an object of interest;
• and
• d) upon determining that a change of significance has been made to an object of interest, using the list of interested parties interested in the object of interest that has changed to notify the interested parties interested in the object of interest that has changed.

In a distributed computing system having a network of computers linked for accessing objects distributed among said computers, some of said computers executing object access software for enabling interested parties to request access to said objects, a computer-implemented method of operating at least one of said computers for automatically notifying interested parties when a change is made to a component of an object defined as a neighborhood or cluster of semantically related objects, said computer-implemented method comprising the steps of:

• a) maintaining in memory a list of interested parties interested in said object defined as a neighborhood or cluster of semantically related objects;
• b) determining whether a change has occurred in said object defined as a neighborhood or cluster of semantically related objects;
• c) upon determining that a change has occurred in said object defined as a neighborhood or cluster of semantically related objects, notifying interested parties by using said list of interested parties interested in said object defined as a neighborhood or cluster of semantically related objects;
• which further includes receiving from one of said interested parties a specification of said object defined as a neighborhood or cluster of semantically related objects, wherein said specification is a search specification of key words.

In a distributed computing system having a network of computers linked for accessing objects distributed among said computers, some of said computers executing object access software for enabling interested parties to request access to said objects, a computer-implemented method of operating at least one of said computers based on time-value of information in said objects, said computer-implemented method comprising the steps of:

• a) receiving from the interested parties specifications of objects of interest;
• b) maintaining in memory a list of the interested parties interested in the objects of interest;
• c) evaluating whether a time-value of each object of interest exceeds a threshold to determine whether said each object of interest has sufficient information value to notify the interested parties interested in said each object of interest;
• and
• d) upon determining that said each object of interest has sufficient information value to notify the interested parties interested in said each object of interest, notifying the interested parties interested in said each object of interest.

In a distributed computing system having a network of computers linked for accessing objects distributed among said computers, some of said computers executing object access software for enabling interested parties to request access to said objects, a computer-implemented method of operating at least one of said computers based on time-value of information in said objects, said computer-implemented method comprising the steps of:

• a) receiving from the interested parties specifications of objects of interest;
• b) maintaining in memory a list of the interested parties interested in the objects of interest;
• c) evaluating whether a time-value of each object of interest exceeds a threshold to determine whether said each object of interest has sufficient information value to notify the interested parties interested in said each object of interest;
• and
• d) upon determining that said each object of interest has sufficient information value to notify the interested parties interested in said each object of interest, notifying the interested parties interested in said each object of interest;
• which further includes maintaining in memory a list of time-value calculations for each of said interested parties, and using said time-value calculations for evaluating whether said each object of interest has sufficient information value to notify each of the interested parties interested in said each object of interest.

In a distributed computing system having a network of computers linked for accessing objects distributed among said computers, some of said computers executing object access software for enabling interested parties to request access to said objects, a computer-implemented method of operating at least one of said computers based on time-value of information in said objects, said computer-implemented method comprising the steps of:

• a) receiving from the interested parties specifications of objects of interest;
• b) maintaining in memory a list of the interested parties interested in the objects of interest;
• c) evaluating whether a time-value of each object of interest exceeds a threshold to determine whether said each object of interest has sufficient information value to notify the interested parties interested in said each object of interest;
• and
• d) upon determining that said each object of interest has sufficient information value to notify the interested parties interested in said each object of interest, notifying the interested parties interested in said each object of interest;
• which further includes receiving from the interested parties specifications for evaluating the time-value of objects of interest to the interested parties.

In a distributed computing system having a network of computers linked for accessing objects distributed among said computers, some of said computers executing object access software for enabling interested parties to request access to said objects, a computer-implemented method of operating at least one of said computers based on time-value of information in said objects, said computer-implemented method comprising the steps of:

• a) receiving from said interested parties specifications of objects of interest, and specifications of significant information value for said objects of interest;
• b) maintaining in memory a list of interested parties interested in the objects of interest;
• c) evaluating said specifications of significant information value for said objects of interest to determine whether each object of interest has sufficient information value to notify the interested parties interested in said each object of interest;
• and
• d) upon determining that said each object of interest has sufficient information value to notify the interested parties interested in said each object of interest, notifying the interested parties interested in said each object of interest.

In a distributed computing system having a network of computers linked for accessing objects distributed among said computers, some of said computers executing object access software for enabling interested parties to request access to said objects, a computer-implemented method of operating at least one of said computers based on time-value of information in said objects, said computer-implemented method comprising the steps of:

• a) receiving from said interested parties specifications of objects of interest, and specifications of significant information value for said objects of interest;
• b) maintaining in memory a list of interested parties interested in the objects of interest;
• c) evaluating said specifications of significant information value for said objects of interest to determine whether each object of interest has sufficient information value to notify the interested parties interested in said each object of interest;
• and
• d) upon determining that said each object of interest has sufficient information value to notify the interested parties interested in said each object of interest, notifying the interested parties interested in said each object of interest;
• wherein one of said specifications of significant information value for said objects of interest is a time-value calculation specified by one of said interested parties for one of said objects of interest, and said time-value calculation is evaluated to determine whether said one of said objects of interest has sufficient information value to notify said one of said interested parties.

In a distributed computing system having a network of computers linked for accessing objects distributed among said computers, some of said computers executing object access software for enabling interested parties to request access to said objects, a computer-implemented method of operating at least one of said computers based on time-value of information in said objects, said computer-implemented method comprising the steps of:

• a) receiving from said interested parties specifications of objects of interest, and specifications of significant information value for said objects of interest;
• b) maintaining in memory a list of interested parties interested in the objects of interest;
• c) evaluating said specifications of significant information value for said objects of interest to determine whether each object of interest has sufficient information value to notify the interested parties interested in said each object of interest;
• and
• d) upon determining that said each object of interest has sufficient information value to notify the interested parties interested in said each object of interest, notifying the interested parties interested in said each object of interest;
• wherein one of said specifications of significant information value for said objects of interest is knowledge specified by one of said interested parties for one of said objects of interest, and said knowledge is evaluated by a knowledge-based system to determine whether said one of said objects of interest has sufficient information value to notify said one of said interested parties.

In a distributed computing system having a network of computers linked for accessing objects distributed among said computers, some of said computers being client computers executing object access software for permitting users to view information from said objects, a computer-implemented method of operating at least one of said computers for automatically notifying said client computers when conditions of interest occur with respect to objects of interest, said computer-implemented method comprising the steps of:

• a) accepting from each client computer a specification of an object of interest, said specification including a resource locator identifying one of said computers containing said object of interest;
• b) maintaining in memory a list of the client computers interested in said object of interest;
• c) checking a cache memory for said object of interest, and when said cache memory does not contain said object of interest, obtaining said object of interest by transmitting said object of interest over said network from said one of said computers containing said object of interest to said cache memory, storing said object of interest in said cache memory, and modifying the resource locator for said object of interest to create a modified resource locator for said object of interest identifying said cache memory as a location for obtaining said object of interest;
• d) transmitting the modified resource locator for said object of interest from said cache memory to said each client computer, said each client computer thereafter using said modified locator for said object of interest to fetch said object of interest from said cache memory;
• e) detecting a condition of interest with respect to said object of interest, and in response to detecting the condition of interest with respect to said object of interest, determining whether a notification of the condition of interest would then be desirable for each of the client computers in the list of client computers interested in said object of interest;
• and
• f) upon determining that a notification of the condition of interest would then be desirable for one of the client computers in response to detecting the condition of interest in said object of interest, notifying said one of the client computers of the occurrence of the condition of interest in said object of interest.

In a distributed computing system having a network of computers linked for accessing objects distributed among said computers, some of said computers executing object access software enabling interested parties to request access to said objects, a computer-implemented method of operating at least one of said computers for automatically notifying said interested parties when conditions of interest occur with respect to objects of interest, said computer-implemented method comprising the steps of:

• a) accepting from said interested parties specifications of the objects of interest, and specifications of respective conditions of interest in the objects of interest;
• b) for each of the objects of interest, maintaining in memory a respective list of the interested parties and the conditions of interest for the interested parties;
• and
• c) checking whether a respective condition of interest occurs with respect to an object of interest, and when a respective condition of interest is found with respect to an object of interest, determining whether or not notification of the occurrence of the condition of interest to at least one of the interested parties would then be desirable, and when notification of the condition of interest to said at least one of the interested parties would then be desirable, notifying said at least one of the interested parties of the occurrence of the condition of interest with respect to the object of interest.

In a distributed computing system having a network of computers linked for transmission of information about objects distributed among said computers, some of said computers executing software enabling interested parties to be provided with information about objects that the interested parties are interested in, a computer-implemented method of operating said computers for providing information about changed objects to interested parties that are interested in the information about the changed objects, said computer-implemented method comprising:

• (a) detecting a change in a changed object of interest residing at one of said computers in said distributed computing system, and upon detecting the change in the changed object of interest, the first computer providing information about the changed object of interest to a cache memory of a second one of said computers in said distributed computing system, said cache memory maintaining information about the changed object of interest;
• and then
• (b) at an appropriate time after said cache memory receives information about the changed object of interest, the second computer forwarding information about the changed object of interest from said cache memory to a third one of said computers of an interested party interested in the changed object of interest;
• wherein the second computer waits a certain amount of time after receipt of information about the changed object of interest before forwarding information about the changed object of interest to the third computer of the interested party interested in the changed object of interest in order to place an appropriate limit on the frequency of transmission of information about the changed object of interest.

In a distributed computing system having a network of computers linked for transmission of information about objects distributed among said computers, some of said computers executing software enabling interested parties to be provided with information about objects that the interested parties are interested in, a computer-implemented method of operating said computers for providing information about changed objects to interested parties that are interested in the information about the changed objects, said computer-implemented method comprising:

• (a) detecting a change in a changed object of interest residing at one of said computers in said distributed computing system, and upon detecting the change in the changed object of interest, the first computer providing information about the changed object of interest to a cache memory of a second one of said computers in said distributed computing system, said cache memory maintaining information about the changed object of interest;
• and then
• (b) at an appropriate time after said cache memory receives information about the changed object of interest. the second computer forwarding information about the changed object of interest from said cache memory to a third one of said computers of an interested party interested in the changed object of interest;
• wherein the second computer maintains a list of interested parties that are interested in the changed object of interest, and wherein the second computer also maintains, for each of the interested parties in the list, information specifying when it is appropriate to forward information about the changed object of interest from said cache memory to said each of the interested parties in the list.

In a distributed computing system having a network of computers linked for transmission of information about objects distributed among said computers, some of said computers executing software enabling interested parties to be provided with information about objects that the interested parties are interested in, a computer-implemented method of operating said computers for providing information about changed objects to interested parties that are interested in the information about the changed objects. said computer-implemented method comprising:

• (a) detecting a change in a changed object of interest residing at one of said computers in said distributed computing system, and upon detecting the change in the changed object of interest, the first computer providing information about the changed object of interest to a cache memory of a second one of said computers in said distributed computing system, said cache memory maintaining information about the changed object of interest;
• and then
• (b) at an appropriate time after said cache memory receives information about the changed object of interest, the second computer forwarding information about the changed object of interest from said cache memory to a third one of said computers of an interested party interested in the changed object of interest;
• wherein the second one of the computers is responsive to a demand from an interested party for information about the changed object of interest by transmitting a summary of changes in the changed object of interest from the cache memory to the interested party demanding information about the changed object of interest.

In a distributed computing system having a network of computers linked for transmission of information about objects distributed among said computers, some of said computers executing software enabling interested parties to be provided with information about objects that the interested parties are interested in, a computer-implemented method of operating said computers for providing information about changed objects to interested parties that are interested in the information about the changed objects, said computer-implemented method comprising:

• (a) detecting a change in a changed object of interest residing at one of said computers in said distributed computing system, and upon detecting the change in the changed object of interest, the first computer Providing information about the changed object of interest to a cache memory of a second one of said computers in said distributed computing system, said cache memory maintaining information about the changed object of interest;
• and then
• (b) at an appropriate time after said cache memory receives information about the changed object of interest, the second computer forwarding information about the changed object of interest from said cache memory to a third one of said computers of an interested party interested in the changed object of interest;
• wherein the second one of the computers maintains in said cache memory a history of a sequence of changes in the changed object of interest, and the second one of the computers is responsive to a demand from an interested party for a summary of changes in the changed object of interest by transmitting information about the sequence of changes in the object of interest from the cache memory to the interested party demanding the summary of changes in the changed object of interest.

In a distributed computing system having a network of computers linked for transmission of information about objects distributed among said computers, some of said computers executing software enabling interested parties to be provided with information about objects that the interested parties are interested in, a computer-implemented method of operating said computers for providing information about changed objects to interested parties that are interested in the information about the changed objects, said computer-implemented method comprising:

• (a) detecting a change in a changed object of interest residing at a first one of said computers in said distributed computing system, and upon detecting the change in the changed object of interest, the first computer providing information about the changed object of interest to a cache memory of a second one of said computers in said distributed computing system;
• (b) the second computer maintaining in said cache memory current information about the changed object of interest;
• and
• (c) in response to a demand from an interested party interested in the changed object of interest, the second computer forwarding information about the changed object of interest from said cache memory to a third one of said computers of the interested party interested in the changed object of interest.

In a distributed computing system having a network of computers linked for transmission of information about objects distributed among said computers, some of said computers executing software enabling interested parties to be provided with information about objects that the interested parties are interested in, a computer-implemented method of operating said computers for providing information about changed objects to interested parties that are interested in the information about the changed objects, said computer-implemented method comprising:

• (a) detecting a change in a changed object of interest residing at a first one of said computers in said distributed computing system, and upon detecting the chance in the changed object of interest, the first computer providing information about the changed object of interest to a cache memory of a second one of said computers in said distributed computing system;
• (b) the second computer maintaining in said cache memory current information about the changed object of interest;
• and
• (c) in response to a demand from an interested party interested in the changed object of interest, the second computer forwarding information about the changed object of interest from said cache memory to a third one of said computers of the interested party interested in the changed object of interest;
• wherein the second computer responds to receipt of information about the changed object of interest from the first computer by notifying the interested party that a change has occurred in the changed object of interest, and then the second computer waits for a demand from the interested party for information that includes changes in the changed object of interest, and in response to a demand from the interested party for information that includes changes in the changed object of interest, the second computer forwards to the interested party information that incudes changes in the changed object of interest.

In a distributed computing system having a network of computers linked for transmission of information about objects distributed among said computers, some of said computers executing software enabling interested parties to be provided with information about objects that the interested parties are interested in, a computer-implemented method of operating said computers for providing information about changed objects to interested parties that are interested in the information about the changed objects, said computer-implemented method comprising:

• (a) detecting a chance in a changed object of interest residing at a first one of said computers in said distributed computing system, and upon detecting the change in the changed object of interest, the first computer providing information about the changed object of interest to a cache memory of a second one of said computers in said distributed computing system;
• (b) the second computer maintaining in said cache memory current information about the changed object of interest;
• and
• (c) in response to a demand from an interested party interested in the changed object of interest, the second computer forwarding information about the changed object of interest from said cache memory to a third one of said computers of the interested party interested in the changed object of interest;
• wherein the second computer provides a summary of changes in the changed object to the interested party, and wherein the second computer responds to a demand from the interested party for a version of the changed object by providing a version of the changed object to the interested party.

In a distributed computing system having a network of computers linked for transmission of information about objects distributed among said computers, some of said computers executing software enabling interested parties to be provided with information about objects that the interested parties are interested in, a computer-implemented method of operating said computers for providing information about changed objects to interested parties that are interested in the information about the changed objects, said computer-implemented method comprising:

• (a) maintaining in a cache memory of a first one of said computers information defining a current version of a changed object residing in a second one of said computers and also maintaining in the cache memory information defining at least one prior version of the changed object residing in the second one of said computers;
• (b) the first one of said computers responding to a request from an interested party for a summary of changes in the changed object by providing from the cache memory a summary of changes in the changed object;
• and
• (c) the first one of said computers responding to a request from an interested party for a specified version of the changed object by providing from the cache memory the specified version of the changed object.

In a distributed computing system having a network of computers linked for transmission of information about objects distributed among said computers, some of said computers executing software enabling interested parties to be provided with information about objects that the interested parties are interested in, a computer-implemented method of operating said computers for providing information about changed objects to interested parties that are interested in the information about the changed objects, said computer-implemented method comprising:

• (a) at least one of said computers of an interested party maintaining a local cache of objects of interest to the interested party;
• (b) said at least one of said computers receiving from another computer in the network a current version of an object of interest to the interested party;
• and
• (c) said at least one of said computers comparing the current version of the object of interest to a version of the object of interest in the local cache to identify changes between the current version of the object of interest and the version of the object of interest in the local cache, and to indicate to the interested party the identified changes between the current version of the object of interest and the version of the object of interest in the local cache;
• wherein the network automatically forwards to said at least one of said computers an indication that a change has been made to the object of interest in response to a change being made to the object of interest.

In a distributed computing system having a network of computers linked for transmission of information about objects distributed among said computers, some of said computers executing software enabling interested parties to be provided with information about objects that the interested parties are interested in. a computer-implemented method of operating said computers for providing information about changed objects to interested parties that are interested in the information about the changed objects, said computer-implemented method comprising:

• (a) at least one of said computers of an interested party maintaining a local cache of objects of interest to the interested party;
• (b) said at least one of said computers receiving from another computer in the network a current version of an object of interest to the interested party;
• and
• (c) said at least one of said computers comparing the current version of the object of interest to a version of the object of interest in the local cache to identify chances between the current version of the object of interest and the version of the object of interest in the local cache, and to indicate to the interested party the identified changes between the current version of the object of interest and the version of the object of interest in the local cache;
• wherein the network automatically forwards to said at least one of said computers an indication that a change has been made to the object of interest in response to a change being made to the object of interest, and wherein the interested party specifies an update frequency used by the network for limiting the frequency at which the network automatically forwards to said at least one of said computers an indication that a change has been made to the object of interest in response to a change being made to the object of interest.

In a distributed computing system having a network of computers linked for transmission of information about objects distributed among said computers, some of said computers executing software enabling interested parties to be provided with information about objects that the interested parties are interested in, a computer-implemented method of operating said computers for providing information about updates to a software product of interest from at least one computer in said distributed computing system to interested parties that are interested in the software updates, said computer-implemented method comprising:

• a) maintaining in a memory in said distributed computing system a list of the interested parties interested in the updates to the software product, the list being accessed by interested parties via said distributed computing system to register the current interest of the interested parties in the software product;
• and
• b) distributing information about an update to the software product by accessing the list of the interested parties to obtain an identification of the interested parties that are currently interested in the software product, and using the identification of the interested parties that are currently interested in the software product to distribute information about the update to the software product through the distributed computing system from said at least one of the computers to the interested parties.

In a computer network having a plurality of addressable sites where network clients can access stored information, a method of change notification, said method comprising the steps of:

• a) network clients interested in a particular object sending requests for change notification to a respective site in the network for receiving network client requests for change notification with respect to the particular object;
• b) maintaining a list of the network clients from which requests for change notification are received at said respective site;
• and
• c) in response to a change being made in the particular object, said list being inspected to send change notifications to the network clients on said list, whereby the network clients interested in the particular object do not need to poll said respective site to be notified of a change in the particular object.