Automatic retrieval of changed files by a network software agent

• US 6,029,175 A
• Filed: 06/07/1996
• Issued: 02/22/2000
• Est. Priority Date: 10/26/1995
• Status: Expired due to Fees

• Current Assignee: Teknowledge Corporation
• Original Assignee: Teknowledge Corporation
• Inventors: Manley, James E., McMahan, Christopher B., Chow, Yen-whei, Jacobstein, Neil A., Hayes-Roth, Frederick A.
• Primary Examiner(s): Kulik, Paul V.
• Application Number:
  US08/664,323
• Time in Patent Office: 1,355 Days
• Field of Search: 707/104, 707/1, 707/10, 707/200, 707/201, 707/203, 395/200.33, 395/200.32, 395/200.34, 395/200.35, 709/202, 709/203, 709/219
• US Class Current: 1/1
• CPC Class Codes: G06F 16/957 Browsing optimisation, e.g. caching or content distillation
• CPC Class Codes: H04L 67/02 based on web technology, e.g. hypertext transfer protocol [HTTP]
• CPC Class Codes: H04L 67/306 User profiles
• CPC Class Codes: H04L 67/51 Discovery or management thereof, e.g. service location protocol [SLP] or web services
• CPC Class Codes: H04L 67/535 Tracking the activity of the user network monitoring arrangements H04L43/00; recording of computer activity G06F11/34
• CPC Class Codes: H04L 67/55 Push-based network services
• CPC Class Codes: H04L 67/5682 Policies or rules for updating, deleting or replacing the stored data
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]
• CPC Class Codes: H04L 9/40 Network security protocols
• CPC Class Codes: Y10S 707/99945 Object-oriented database structure processing
• CPC Class Codes: Y10S 707/99948 Application of database or data structure, e.g. distributed, multimedia, or image
• CPC Class Codes: Y10S 707/99952 Coherency, e.g. same view to multiple users
• CPC Class Codes: Y10S 707/99953 Recoverability

Abstract

An intelligent network agent intercepts transactions between clients and servers to perform Distributed Information Logistics Services (DILS) functions such as automatically retrieving updated files from remote servers and delivering them to local client programs. For example, HTTP clients and HTTPD servers are connectionless and stateless, thus there is no way for a server to update a browser automatically when an HTML document is changed. The invention provides a method to update any number of clients from any number of servers without making any changes to currently existing HTTP clients or HTTPD servers. Furthermore, the invention can provide various other DILS services for clients to reduce latency and communication costs for members of a group with interests in similar objects. For example, the intelligent network agent maintains a cache of objects of interest to the group of clients, a log of changes to the objects, a list of the clients interested in the objects, a list of significant change detection methods for the objects, a list of search specifications for the objects, lists of client notification methods, and lists of general interest specifications for the clients.

Claims

1. 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 for display of accessed ones of 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) 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 interested party in the list of interested parties interested in the object of interest in which the occurrence of change is detected; and

d) upon determining that an update notification would then be desirable for one of the interested parties in response to detecting the occurrence of change in one of said objects of interest, notifying said one of the interested parties of the occurrence of change in said one of said objects of interest for display of said one of said objects of interest.

2. The method as claimed in claim 1, wherein said interested parties are HTTP-compliant client browsers, said specifications are accepted from said interested parties by following an HTTP client-to-server data transmission protocol, and said one of said interested parties is notified of the occurrence of change in said one of said objects of interest by following an HTTP server-to-client data transmission protocol.

3. The method as claimed in claim 1, which further includes:

in response to accepting a specification of each object of interest, checking a cache memory for said each object of interest, and when said cache memory does not contain said each object of interest, obtaining said each object of interest by transmitting said each object of interest over said network from a computer in said network to said cache memory, and storing said each object of interest in said cache memory; and

wherein said one of said objects is fetched from said cache memory for said one of said interested parties for display.

4. The method as claimed in claim 1, which further includes highlighting changes in said one of said objects of interest when displaying said one of said objects of interest.

5. The method as claimed in claim 1, which further includes accepting a desired update notification frequency from each interested party, and using the desired update notification frequency for determining whether an update notification would then be desirable for each interested party in the list of interested parties interested in the object of interest in which the occurrence of change is detected.

6. The method as claimed in claim 1, which further includes recording, for each object of interest, the time when said each object of interest was updated, and inspecting the recorded time when each object of interest was updated for detecting the occurrence of a change in said each object of interest.

7. The method as claimed in claim 1, wherein said specifications include specifications of aggregates of objects, and said method includes determining the objects in the specified aggregates of objects for maintaining in memory the list of the interested parties interested in each of the objects of interest.

8. The method as claimed in claim 1, wherein the specifications include abstract characterizations of attributes of objects, and further including the step of matching said abstract characterizations with attributes of objects stored in said distributed computing system to determine objects that are specified by said abstract characterizations.

9. 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.

10. The method as claimed in claim 9, which includes maintaining a list of mechanisms used for notifying client browsers of the occurrence of change in the respective objects of interest.

11. 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.

12. The method as claimed in claim 11, wherein said client browsers are HTTP-compliant client browsers following an HTTP client-to-server data transmission protocol, and said method further includes checking said cache for an object of interest identified by a resource locator in a specification received from one of said client browsers in said group of client browsers, and when said cache does not contain the object of interest identified by the resource locator, redirecting said one of said specifications to one of said computers identified by said resource locator as a location for obtaining the object of interest.

13. The method as claimed in claim 12, wherein said cache stores objects of interest obtained from various ones of said computers in said distributed computing system, and said method includes transmitting the objects of interest from said cache to said client browsers in said group of client browsers instead of transmitting the objects of interest from said various ones of said computers in said distributed computing system to said client browsers in said group of client browsers in order to reduce latency for access to the objects of interest stored in said cache.

14. The method as claimed in claim 12, wherein said cache stores objects of interest obtained from various ones of said computers in said distributed computing system, and said method includes transmitting the objects of interest from said cache to said client browsers in said group of client browsers instead of transmitting the objects of interest from said various ones of said computers in said distributed computing system to said client browsers in said group of client browsers in order to reduce communication access costs for access to the objects of interest stored in said cache.

15. The method as claimed in claim 11, which further includes selecting among alternative sources for objects of interest to be stored in said cache by employing performance, cost or quality statistics on resource accesses from said alternative sources.

16. The method as claimed in claim 15, which further includes collecting and maintaining said performance, cost or quality statistics on resource accesses from said alternative sources.

17. 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.

18. The method as claimed in claim 17, which further includes:

f) recording a first indication of when said one of said objects of interest was last changed;

g) recording a second indication of when said one of the client browsers was last notified of the occurrence of change in said one of said objects of interest;

h) receiving from said one of the client browsers a specification of a desired update notification frequency; and

i) using said first indication, said second indication, and said specification of said desired update notification frequency to determine that an update notification would then be desirable to said one of said client browsers.

19. The method as claimed in claim 17, which further includes recording an indication of changes made to the objects stored in said cache, and providing, to said client browsers in said group of client browsers, summaries of changes made to the objects stored in said cache.

20. 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 for selecting among alternative sources for the objects of interest by optimizing a user objective function trading off communication cost factors against quality of service factors including latency.

21. The distributed computing system as claimed in claim 20, wherein said cache memories are distributed at selected locations around said network, and said client browsers are grouped to be serviced by said cache memories.

22. 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.

23. 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.

24. 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, 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,

wherein said distributed computing system includes, for one of said cache memories, means for receiving resource interest specifications from the client browsers serviced from said one of said cache memories, means for maintaining in said one of said cache memories objects that satisfy said resource interest specification, and means for maintaining a list of mechanisms for sending information to the client browsers serviced from said one of said cache memories.

25. The distributed computing system as claimed in claim 24, wherein said distributed computing system further includes, for said one of said cache memories, means for using said lists of mechanisms to send notice of changes in objects of interest to the client browsers serviced from said one of said cache memories.

26. The distributed computing system as claimed in claim 24, 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.

27. The distributed computing system as claimed in claim 26, further including means for collecting and maintaining said performance, cost or quality statistics on resource accesses from said alternative sources.

28. The method as claimed in claim 24, further including 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.

29. 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.

30. The method as claimed in claim 29, wherein said clients are HTTP-compliant clients, said resource requests are accepted from said clients by following an HTTP client-to-server data transmission protocol, and said resource manager returns the fetched objects and modified resource locators to said clients by following an HTTP server-to-client data transmission protocol.

31. The method as claimed in claim 29, which further includes said resource manager redirecting one of said resource requests to an alternative server expected to produce higher quality information at lower cost.

32. The method as claimed in claim 29, which further includes said resource manager selecting among alternative sources for objects.

33. The method as claimed in claim 32, which further includes said resource manager using information about costs of the alternative sources to select lowest-cost alternative sources for objects.

34. The method as claimed in claim 32, which further includes said resource manager using information about quality and costs of the alternative sources for objects to select among the alternative sources for objects by a trade-off between quality and cost.

35. The method as claimed in claim 32, which further includes said resource manager collecting and maintaining said performance, cost or quality statistics on resource accesses from said alternative sources, and using said statistics on resource accesses for the selecting among the alternative sources for objects.

36. The method as claimed in claim 29, which further includes said resource manager storing in a cache memory objects having respective resource locators that are modified by the resource manager to indicate that the resource manager is a source of the objects, and said resource manager responding to resource requests from said clients by checking said cache memory for objects that satisfy the resource requests, and when said resource manager finds an object in said cache memory that satisfies one of the resource requests, said resource manager transmitting the object from the cache memory to the client requesting the object.

37. The method as claimed in claim 36, which further includes said resource manager redirecting a request from a client for a specified object to a server when the resource manager checks said cache memory for the specified object and the specified object is absent from said cache memory.

38. 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.

39. The method as claimed in claim 38, which further includes said computers executing said object-access software to display said object of interest that has changed, and to highlight changes in said object of interest that has changed.

40. 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.

41. The method as claimed in claim 40, wherein one of said objects of interest contains hyperlinks, and wherein the method includes traversing said hyperlinks to access components of said one of said objects of interest.

42. The method as claimed in claim 40, wherein the object is an aggregate of multiple objects, and wherein the step of determining when an update notification would be desirable for each interested party in the list of interested parties includes determining whether a change has occurred in a specified subset of said multiple objects.

43. The method as claimed in claim 40, wherein the method further includes determining when a change occurs in each of the objects of interest, and determining whether an update notification would be desirable when a change occurs in each of the objects of interest.

44. The method as claimed in claim 40, wherein the method further includes polling a source of an object of interest in order to determine whether an update notification would be desirable.

45. The method as claimed in claim 40, wherein a source of an object of interest produces a change indication when change occurs in the object of interest, and wherein the step of determining whether an update notification would be desirable is responsive to the change indication from the source of the object of interest.

46. 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.

47. The method as claimed in claim 46, which includes maintaining in memory a list of significant change detection methods for each object of interest, and wherein the list of significant change detection methods for each object of interest is used when a change is detected in said each object of interest to determine whether a change of significance has been made in said each object of interest.

48. The method as claimed in claim 46, wherein one of the interested parties in said group of interested parties makes a change of significance to an object of interest to said group of interested parties, and all other interested parties in said group of interested parties are notified virtually simultaneously of the change of significance made by said one of the interested parties in said group of interested parties.

49. 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.

50. The method as claimed in claim 49, 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.

51. 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.

52. The method as claimed in claim 51, which further includes maintaining a list of mechanisms for notifying said interested parties, and using said list of mechanisms for notifying said interested parties when notifying the interested parties interested in said object defined as a neighborhood or cluster of semantically related objects.

53. 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.

54. 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.

55. 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.

56. The method as claimed in claim 55, wherein one of the interested parties specifies a procedure which is executed to evaluate the time-value of one of said objects of interest.

57. The method as claimed in claim 55, wherein one of the interested parties specifies parameters for a function that evaluates the time-value of one of said objects of interest.

58. The method as claimed in claim 55, wherein one of the interested parties specifies knowledge for a knowledge-based system that evaluates the time-value of one of said objects of interest.

59. 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.

60. 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.

61. 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.

62. 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.

63. The method as claimed in claim 62, which includes maintaining a list of mechanisms used for notifying respective client computers of the occurrence of respective conditions of interest in the respective objects of interest.

64. 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.

65. The method as claimed in claim 64, which further includes maintaining in memory a list of mechanisms for notifying the interested parties of the conditions of interest with respect to the objects of interest, and when a notification of the condition of interest would then be desirable for one of the interested parties interested in one of the objects of interest, using the list of mechanisms to notify said one of the interested parties of the condition of interest with respect to said one of the objects of interest.

66. 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.

67. The method as claimed in claim 66, wherein software executed by the third computer provides a client browser that is used for fetching specified objects that are distributed among said computers in said distributed computer system.

68. The method as claimed in claim 66, wherein the second computer maintains in the cache memory information about specified objects and also information about objects in specified general classes of objects.

69. The method as claimed in claim 68, wherein the second computer maintains in the cache memory information about the objects in the specified general classes of objects by searching the network of computers for objects that satisfy a search specification.

70. The method as claimed in claim 69, wherein the search specification defines a set of semantically related objects.

71. 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.

72. 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.

73. 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.

74. 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.

75. 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.

76. 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.

77. 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.

78. 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.

79. The method as claimed in claim 78, wherein the first one of the computers reconstructs a prior version of the changed object from a log of changes in the cache memory and a current version of the changed object in the cache memory.

80. 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.

81. The method as claimed in claim 80, wherein the interested party specifies a criterion used by the network for determining when a change made to the object of interest is sufficiently significant for automatically forwarding 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.

82. The method as claimed in claim 80, wherein the indication that a change has been made to the object of interest is the automatic transmission of the current version of the object of interest to said at least one of the computers.

83. The method as claimed in claim 80, wherein the object of interest is transmitted to said at least one of the computers in response to the party of interest being advised that a change has been made to the object of interest and the party of interest requesting to view at least a changed portion of the object of interest.

84. 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.

85. 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.

86. The method as claimed in claim 85, wherein the update to the software product is automatically downloaded through the distributed computing system from said at least one of the computers to the interested parties that are currently interested in the software product.

87. The method as claimed in claim 85, wherein the update to the software product is downloaded through the distributed computing system from said at least one of the computers to an interested party upon the request of the interested party.

88. The method as claimed in claim 85, wherein the distributed computing system includes the Internet, and the update to the software product is transmitted over the Internet to an interested party.

89. 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.

90. The method of change notification as claimed in claim 89, wherein the object is a commercial product and the method further includes distributing an update of the commercial product to network clients that indicate a desire to obtain the update of the commercial product.

91. The method of change notification as claimed in claim 89, which includes at least one of the network clients on said list sending a request to said respective site to be removed from said list so as not to be notified of a subsequent change in said particular object.

92. The method of change notification as claimed in claim 89, wherein at least one of the network clients interested in said particular object sends a respective specification of a significant change detection method for said particular object for determining whether or not the change in said particular object is of sufficient significance to said at least one of the network clients for a change notification to be sent to said at least one of the network clients, and in response to the change being made in the particular object and upon inspecting said list to send change notifications to the network clients on said list, finding that said at least one of said network clients has sent said respective specification of said significant change detection method for said particular object, and applying said significant change detection method for said particular object to determine whether or not the change having been made in the particular object is of sufficient significance to said at least one of said network clients for a change notification to be sent to said at least one of said network clients.

93. The method of change notification as claimed in claim 89, wherein at least one of the network clients interested in said particular object sends a respective specification of a change notification method to be used for notifying said at least one of the network clients of a change in said particular object, and in response to the change being made in the particular object and upon inspecting said list to send change notifications to the network clients on said list, finding that said at least one of said network clients has sent said respective specification of said change notification method, and using said change notification method for notifying said at least one of said network clients of the change in said particular object.

94. A method of operating a server in a data network to service client requests for access to objects residing at other locations in the data network, said method comprising the steps of:

a) in response to requests from clients in the data network, the server fetching specified objects and delivering the specified objects to the clients in the data network; and

b) in response to an update request from at least one of clients having received at least one of the fetched objects, the server registering said at least one of the clients as desiring update notification with respect to said at least one of the fetched objects, and maintaining a copy of said at least one of the fetched objects in a cache memory, and once a change is made to said at least one of the fetched objects at another location in the data network where said at least one of the fetched objects resides, automatically updating the copy of said at least one of the fetched objects residing in the cache memory without client intervention and notifying said at least one of the clients that said at least one of the fetched objects has changed.

95. The method as claimed in claim 94, wherein the server maintains in the cache memory only those objects that are requested by the clients to be updated automatically.

96. The method as claim 94, wherein the server receives a request from said at least one of the clients to cancel registration for updates for said at least one of the fetched objects, and in response the server cancels registration of said at least one of the clients for updates for said at least one of the fetched objects.