Method and system for maintaining synchronization between a local data cache and a data store

• US 20050050067A1
• Filed: 08/29/2003
• Published: 03/03/2005
• Est. Priority Date: 08/29/2003
• Status: Active Grant

• Current Assignee: Energetic Power Investment Limited
• Original Assignee: Yahoo! Inc. (Apollo Global Management, Inc.)
• Inventors: Seitz, Edward F., Sollicito, Vincent L.
• Granted Patent: US 7,496,607 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 16/9574 of access to content, e.g. by caching
• CPC Class Codes: H04L 67/02 based on web technology, e.g. hypertext transfer protocol [HTTP]
• CPC Class Codes: H04L 67/1095 Replication or mirroring of data, e.g. scheduling or transport for data synchronisation between network nodes
• CPC Class Codes: H04L 67/142 Managing session states for stateless protocols; Signalling session states; State transitions; Keeping-state mechanisms
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]
• CPC Class Codes: Y10S 707/99938 Concurrency, e.g. lock management in shared database
• CPC Class Codes: Y10S 707/99953 Recoverability

Abstract

A method and system for maintaining synchronization between a local data cache and a data store is disclosed. The method includes comparing first validation information and second validation information, and synchronizing first data stored in a local data cache with second data stored in a data store, if the comparison indicates that the synchronizing is needed.

Claims

1. An apparatus comprising:

a local data cache comprising local validation information; and

a client operably coupled to said local data cache, wherein

said client is configured to examine said local validation information, and

said client is configured to synchronize said local data cache with a data store, if said local validation information indicates that said local data cache is not synchronized with said data store.

2. The apparatus of claim 1, wherein

said local data cache is one of a plurality of local data caches.

3. The apparatus of claim 2, wherein

each of said local data caches corresponds to one of a plurality of users.

4. The apparatus of claim 1, wherein

said local data cache is stored as a file in a directory structure of said client.

5. The apparatus of claim 1, wherein

said local data cache is stored as a plurality of files in a directory structure of said client.

6. The apparatus of claim 1, further comprising:

said client is configured to compare said local validation information and current validation information.

7. The apparatus of claim 6, further comprising:

a server, wherein

said server is operably coupled to said data store,

said server is communicatively coupled to said client, and

said server is configured to serve data to said client from said data store.

8. The apparatus of claim 6, wherein

said client, being configured to synchronize said local data cache with said data store, is configured to send synchronization information to said server.

9. The apparatus of claim 8, wherein

said client is configured to generate said synchronization information, if said local validation information indicates that said local data cache is not synchronized with said data store, wherein

said current validation information is received from said server.

10. The apparatus of claim 8, wherein

said server is configured to serve said data from said data store in response to receiving said synchronization information.

11. The apparatus of claim 10, further comprising:

a content server communicatively coupled to said client, wherein

said server is a data server, and

said data store is a server data store.

12. The apparatus of claim 11, wherein

said client, being configured to synchronize said local data cache with said server data store, is configured to send synchronization information to said data server.

13. The apparatus of claim 12, wherein

said client is configured to generate said synchronization information, if said local validation information does not match said current validation information, wherein

said current validation information is received from said server.

14. The apparatus of claim 13, further comprising:

an authentication database; and

an authentication server, wherein

said authentication server is operably coupled to said authentication database,

said authentication server is communicatively coupled to said client, said content server, and

said authentication server is configured to authenticate said client using authentication information stored in said authentication database and to provide said authentication information to said content server.

15. The apparatus of claim 14, wherein

said current validation information is generated using said authentication information.

16. The apparatus of claim 14, wherein

said local validation information is generated using said authentication information.

17. The apparatus of claim 11, wherein

said content server is configured to serve content to said client, and

said data server is configured to serve said data from said server data store to said client.

18. The apparatus of claim 17, wherein

said content is a web page, and

said client is configured to populate a field of said web page using said data.

19. The apparatus of claim 18, wherein

said field is one of a plurality of fields of said web page, and

said client is configured to populate said fields using said data.

20. The apparatus of claim 6, further comprising:

a content server communicatively coupled to said client, wherein

said content server is configured to generate said current validation information and to communicate said current validation information to said client.

21. The apparatus of claim 20, wherein

said client is configured to receive said current validation information, and

said client, being configured to determine if said local validation information indicates that said local data cache is not synchronized with said data store, is configured to compare said local validation information and said current validation information.

22. An apparatus comprising:

a local data cache, wherein

said local data cache comprises local validation information; and

a server, wherein

said server is communicatively coupled to said local data cache,

said server is operatively coupled to a data store,

said server is configured to examine said local validation information, and

said server is configured to synchronize said local data cache with said data store, if said local validation information indicates that said local data cache is not synchronized with said data store.

23. The apparatus of claim 22, further comprising:

said server is configured to compare said local validation information and current validation information.

24. The apparatus of claim 23, wherein

said server is configured to use synchronization information.

25. The apparatus of claim 24, wherein

said server is configured to generate said synchronization information, if said local validation information indicates that said local data cache is not synchronized with said data store.

26. The apparatus of claim 24, wherein

said server is configured to serve data from said data store in response to receiving said synchronization information.

27. A method comprising:

comparing first validation information and second validation information; and

synchronizing first data stored in a local data cache with second data stored in a data store, if said comparing indicates said synchronizing is needed.

28. The method of claim 27, further comprising:

receiving said first validation information.

29. The method of claim 28, wherein

said local data cache comprises said second validation information.

30. The method of claim 28, wherein said synchronizing comprises:

deleting said first data from said local data cache; and

writing said second data to said local data cache.

31. The method of claim 28, wherein said synchronizing comprises:

deleting said local data cache; and

writing a new local data cache.

32. The method of claim 28, wherein

said receiving said first validation information is performed by a client,

said client is communicatively coupled to said a server,

said synchronizing comprises sending synchronization information to said server, and

said data store is operably coupled to said server.

33. The apparatus of claim 32, further comprising:

storing said local data cache as a file in a directory structure of said client.

34. The apparatus of claim 32, further comprising:

storing said local data cache as a plurality of files in a directory structure of said client.

35. The method of claim 34, wherein said synchronizing comprises:

deleting a one of said files; and

writing a new file, wherein said file is another of said files.

36. The method of claim 32, wherein said synchronizing further comprises:

receiving said second data from said server; and

storing said second data in said local data cache.

37. The method of claim 36, wherein said synchronizing further comprises:

causing said server to read said second data from said data store.

38. The method of claim 28, further comprising:

causing a content server to generate said first validation information from authentication information available to said content server.

39. The method of claim 38, further comprising:

sending a request for content to said content server.

40. The method of claim 39, further comprising:

causing said content server to send a response to said request for content, wherein

said response to said request for content comprises said first validation information.

41. The method of claim 39, wherein said synchronizing comprises:

sending said first synchronization information to a data server, wherein

said client is communicatively coupled said data server,

said data store is operably coupled to said data server, and

a response to said request for content from said content server comprises said first validation information.

42. The method of claim 41, wherein said synchronizing further comprises:

receiving said second data from said data server; and

storing said second data in said local data cache.

43. The method of claim 42, wherein said synchronizing further comprises:

causing said data server to read said second data from said data store.

44. The method of claim 28, further comprising:

authenticating a user of said client, wherein

said authenticating is performed by an authentication server communicatively coupled to said client, and

said authenticating comprises

storing authentication information for said user in an authentication database operably coupled to said authentication server, if said authenticating is successful.

45. The method of claim 44, further comprising:

sending a request for content to a content server, wherein said authentication server is communicatively coupled to said content server.

46. The method of claim 45, further comprising:

causing said content server to send a response to said request for content, wherein

said response to said request for content comprises said first validation information.

47. The method of claim 46, further comprising:

causing said authentication server to communicate said authentication information to said content server; and

causing said content server to generate said first validation information using said authentication information.

48. The method of claim 47, wherein said synchronizing comprises:

sending said first synchronization information to a data server, wherein

said client is communicatively coupled said data server, and

said data store is operably coupled to said data server.

49. The method of claim 28, wherein

said local data cache is operably coupled to a client, and

said client is configured to perform said receiving, said comparing and said synchronizing.

50. The method of claim 49, wherein said synchronizing comprises:

sending synchronization information to a server, wherein

said client is communicatively coupled said server, and

said data store is operably coupled to said server.

51. The method of claim 49, wherein

said local data cache comprises said second validation information.

52. The method of claim 51, further comprising:

sending a request for content to a content server.

53. The method of claim 52, further comprising:

causing said content server to generate said first validation information from authentication information available to said content server.

54. The method of claim 53, further comprising:

causing said content server to send a response to said request for content, wherein

said response to said request for content comprises said first validation information.

55. The method of claim 52, wherein said synchronizing comprises:

sending said first synchronization information to a data server, wherein

said client is communicatively coupled said data server,

said data store is operably coupled to said data server, and

a response to said request for content from said content server comprises said first validation information.

56. The method of claim 28, wherein

said local data cache is operably coupled to a client,

said client is communicatively coupled to a server, and

said server is configured to perform said receiving, said comparing and said synchronizing.

57. The method of claim 56, wherein said synchronizing comprises:

receiving synchronization information at said server, wherein

said data store is operably coupled to said server.

58. The method of claim 57, wherein said synchronizing further comprises:

sending said second data to said client; and

causing said client to store said second data in said local data cache.

59. The method of claim 57, further comprising:

receiving a request for content at said server.

60. The method of claim 59, further comprising:

generating said first validation information from authentication information available to said server.

61. The method of claim 60, further comprising:

sending a response to said request for content, wherein

said response to said request for content comprises said first validation information.

62. The method of claim 59, wherein said synchronizing comprises:

receiving said first synchronization information at said server, wherein

said data store is operably coupled to said server, and

a response to said request for content from said server comprises said first validation information.

63. A computer system comprising:

a processor;

computer readable medium coupled to said processor; and

computer code, encoded in said computer readable medium, configured to cause said processor to;

compare first validation information and second validation information; and

synchronize first data stored in a local data cache with second data stored in a data store, if said comparing indicates said synchronizing is needed.

64. The computer system of claim 63, wherein said computer code is further configured to cause said processor to:

receive said first validation information.

65. The computer system of claim 64, wherein

said local data cache comprises said second validation information.

66. The computer system of claim 64, wherein said computer code configured to cause said processor to synchronize is further configured to cause said processor to:

delete said first data from said local data cache; and

write said second data to said local data cache.

67. The computer system of claim 64, wherein said computer code configured to cause said processor to synchronize is further configured to cause said processor to:

delete said local data cache; and

write a new local data cache.

68. The computer system of claim 64, wherein

said computer system is a client,

said client is communicatively coupled to a server,

said synchronizing comprises sending synchronization information to said server, and

said data store is operably coupled to said server.

69. The computer system of claim 68, wherein said computer code is further configured to cause said processor to:

store said local data cache as a file in a directory structure of said client.

70. The computer system of claim 68, wherein said computer code is further configured to cause said processor to:

store said local data cache as a plurality of files in a directory structure of said client.

71. The computer system of claim 70, wherein said computer code configured to cause said processor to synchronize is further configured to cause said processor to:

delete a one of said files; and

write a new file, wherein said file is another of said files.

72. The computer system of claim 68, wherein said computer code configured to cause said processor to synchronize is further configured to cause said processor to:

receive said second data from said server; and

store said second data in said local data cache.

73. The computer system of claim 72, wherein said computer code configured to cause said processor to synchronize is further configured to cause said processor to:

cause said server to read said second data from said data store.

74. The computer system of claim 64, wherein said computer code is further configured to cause said processor to:

cause a content server to generate said first validation information from authentication information available to said content server.

75. The computer system of claim 74, wherein said computer code is further configured to cause said processor to:

send a request for content to said content server.

76. The computer system of claim 75, wherein said computer code is further configured to cause said processor to:

cause said content server to send a response to said request for content, wherein

said response to said request for content comprises said first validation information.

77. The computer system of claim 75, wherein said computer code configured to cause said processor to synchronize is further configured to cause said processor to:

send said first synchronization information to a data server, wherein

said client is communicatively coupled said data server,

said data store is operably coupled to said data server, and

a response to said request for content from said content server comprises said first validation information.

78. The computer system of claim 77, wherein said computer code configured to cause said processor to synchronize is further configured to cause said processor to:

receive said second data from said data server; and

store said second data in said local data cache.

79. The computer system of claim 78, wherein said computer code configured to cause said processor to synchronize is further configured to cause said processor to:

cause said data server to read said second data from said data store.

80. The computer system of claim 64, wherein said computer code is further configured to cause said processor to:

cause a user of said client to be authenticated, wherein

said authentication is performed by an authentication server communicatively coupled to said client, and

store authentication information for said user in an authentication database operably coupled to said authentication server, if said authentication is successful.

81. The computer system of claim 80, wherein said computer code is further configured to cause said processor to:

send a request for content to a content server, wherein said authentication server is communicatively coupled to said content server.

82. The computer system of claim 81, wherein said computer code is further configured to cause said processor to:

cause said content server to send a response to said request for content, wherein

said response to said request for content comprises said first validation information.

83. The computer system of claim 82, wherein said computer code is further configured to cause said processor to:

cause said authentication server to communicate said authentication information to said content server; and

cause said content server to generate said first validation information using said authentication information.

84. The computer system of claim 83, wherein said computer code configured to cause said processor to synchronize is further configured to cause said processor to:

send said first synchronization information to a data server, wherein

said client is communicatively coupled said data server, and

said data store is operably coupled to said data server.

85. The computer system of claim 64, wherein

said local data cache is operably coupled to a client, and

said client comprises said computer code configured to cause said processor to receive, compare and synchronize.

86. The computer system of claim 85, wherein said computer code configured to cause said processor to synchronize is further configured to cause said processor to:

send synchronization information to a server, wherein

said client is communicatively coupled said server, and

said data store is operably coupled to said server.

87. The computer system of claim 85, wherein

said local data cache comprises said second validation information.

88. The computer system of claim 87, wherein said computer code is further configured to cause said processor to:

send a request for content to a content server.

89. The computer system of claim 88, wherein said computer code is further configured to cause said processor to:

cause said content server to generate said first validation information from authentication information available to said content server.

90. The computer system of claim 89, wherein said computer code is further configured to cause said processor to:

cause said content server to send a response to said request for content, wherein

said response to said request for content comprises said first validation information.

91. The computer system of claim 88, wherein said computer code configured to cause said processor to synchronize is further configured to cause said processor to:

send said first synchronization information to a data server, wherein

said client is communicatively coupled said data server,

said data store is operably coupled to said data server, and

a response to said request for content from said content server comprises said first validation information.

92. The computer system of claim 64, wherein

said local data cache is operably coupled to a client,

said client is communicatively coupled to a server, and

said server comprises said computer code configured to cause said processor to receive, compare and synchronize.

93. The computer system of claim 92, wherein said computer code configured to cause said processor to synchronize is further configured to cause said processor to:

receive synchronization information, wherein

said data store is operably coupled to said server.

94. The computer system of claim 93, wherein said computer code configured to cause said processor to synchronize is further configured to cause said processor to:

send said second data to said client; and

cause said client to store said second data in said local data cache.

95. The computer system of claim 93, wherein said computer code is further configured to cause said processor to:

receive a request for content.

96. The computer system of claim 95, wherein said computer code is further configured to cause said processor to:

generate said first validation information from authentication information available to said server.

97. The computer system of claim 96, wherein said computer code is further configured to cause said processor to:

send a response to said request for content, wherein

said response to said request for content comprises said first validation 5 information.

98. The computer system of claim 95, wherein said computer code configured to cause said processor to synchronize is further configured to cause said processor to:

receive said first synchronization information at said server, wherein

said data store is operably coupled to said server, and

a response to said request for content from said server comprises said first validation information.

99. A computer program product comprising:

a first set of instructions, executable on a computer system, configured to compare first validation information and second validation information;

a second set of instructions, executable on said computer system, configured to synchronize first data stored in a local data cache with second data stored in a data store, if said comparing indicates said synchronizing is needed; and

computer readable media, wherein said computer program product is encoded in said computer readable media.

100. The computer program product of claim 99, further comprising:

a third set of instructions, executable on said computer system, configured to receive said first validation information.

101. The computer program product of claim 100, wherein

said local data cache comprises said second validation information.

102. The computer program product of claim 100, wherein said second set of instructions comprises:

a first subset of instructions, executable on said computer system, configured to delete said first data from said local data cache; and

a second subset of instructions, executable on said computer system, configured to write said second data to said local data cache.

103. The computer program product of claim 100, wherein said second set of instructions comprises:

a first subset of instructions, executable on said computer system, configured to delete said local data cache; and

a second subset of instructions, executable on said computer system, configured to write a new local data cache.

104. The computer program product of claim 100, wherein

said computer program product is resident on a client,

said client is communicatively coupled to a server,

said synchronizing comprises sending synchronization information to said server, and

said data store is operably coupled to said server.

105. The computer program product of claim 104, further comprising:

a fourth set of instructions, executable on said computer system, configured to store said local data cache as a file in a directory structure of said client.

106. The computer program product of claim 104, further comprising:

a fourth set of instructions, executable on said computer system, configured to store said local data cache as a plurality of files in a directory structure of said client.

107. The computer program product of claim 106, wherein said second set of instructions comprises:

a first subset of instructions, executable on said computer system, configured to delete a one of said files; and

a second subset of instructions, executable on said computer system, configured to write a new file, wherein said file is another of said files.

108. The computer program product of claim 104, wherein said second set of instructions comprises:

a first subset of instructions, executable on said computer system, configured to receive said second data from said server; and

a second subset of instructions, executable on said computer system, configured to store said second data in said local data cache.

109. The computer program product of claim 108, wherein said second set of instructions comprises:

a third subset of instructions, executable on said computer system, configured to cause said server to read said second data from said data store.

110. The computer program product of claim 100, further comprising:

a fourth set of instructions, executable on said computer system, configured to cause a content server to generate said first validation information from authentication information available to said content server.

111. The computer program product of claim 110, further comprising:

a fifth set of instructions, executable on said computer system, configured to send a request for content to said content server.

112. The computer program product of claim 111, further comprising:

a sixth set of instructions, executable on said computer system, configured to cause said content server to send a response to said request for content, wherein

said response to said request for content comprises said first validation information.

113. The computer program product of claim 112, wherein said second set of instructions comprises:

a first subset of instructions, executable on said computer system, configured to send said first synchronization information to a data server, wherein

said client is communicatively coupled said data server,

said data store is operably coupled to said data server, and

a response to said request for content from said content server comprises said first validation information.

114. The computer program product of claim 113, wherein said second set of instructions comprises:

a second subset of instructions, executable on said computer system, configured to receive said second data from said data server; and

a third subset of instructions, executable on said computer system, configured to store said second data in said local data cache.

115. The computer program product of claim 114, wherein said second set of instructions comprises:

a fourth subset of instructions, executable on said computer system, configured to cause said data server to read said second data from said data store.

116. The computer program product of claim 100, further comprising:

a fourth set of instructions, executable on said computer system, configured to cause a user of a client to be authenticated, wherein

said computer program product is resident on a client,

said authentication is performed by an authentication server communicatively coupled to said client, and

a fifth set of instructions, executable on said computer system, configured to store authentication information for said user in an authentication database operably coupled to said authentication server, if said authenticating is successful.

117. The computer program product of claim 116, further comprising:

a sixth set of instructions, executable on said computer system, configured to send a request for content to a content server, wherein said authentication server is communicatively coupled to said content server.

118. The computer program product of claim 117, further comprising:

a seventh set of instructions, executable on said computer system, configured to cause said content server to send a response to said request for content, wherein

said response to said request for content comprises said first validation information.

119. The computer program product of claim 118, further comprising:

a eighth set of instructions, executable on said computer system, configured to cause said authentication server to communicate said authentication information to said content server; and

a ninth set of instructions, executable on said computer system, configured to cause said content server to generate said first validation information using said authentication information.

120. The computer program product of claim 119, wherein said second set of instructions comprises:

a first subset of instructions, executable on said computer system, configured to send said first synchronization information to a data server, wherein

said client is communicatively coupled said data server, and

said data store is operably coupled to said data server.

121. The computer program product of claim 100, wherein

said local data cache is operably coupled to a client, and

said client executes said first, said second and said third sets of instructions.

122. The computer program product of claim 121, wherein said second set of instructions comprises:

a first subset of instructions, executable on said computer system, configured to send synchronization information to a server, wherein

said client is communicatively coupled said server, and

said data store is operably coupled to said server.

123. The computer program product of claim 121, wherein

said local data cache comprises said second validation information.

124. The computer program product of claim 123, further comprising:

a fourth set of instructions, executable on said computer system, configured to send a request for content to a content server.

125. The computer program product of claim 124, further comprising:

a fifth set of instructions, executable on said computer system, configured to cause said content server to generate said first validation information from authentication information available to said content server.

126. The computer program product of claim 125, further comprising:

a sixth set of instructions, executable on said computer system, configured to cause said content server to send a response to said request for content, wherein

said response to said request for content comprises said first validation information.

127. The computer program product of claim 124, wherein said second set of instructions comprises:

a first subset of instructions, executable on said computer system, configured to send said first synchronization information to a data server, wherein

said client is communicatively coupled said data server,

said data store is operably coupled to said data server, and

a response to said request for content from said content server comprises said first validation information.

128. The computer program product of claim 100, wherein

said local data cache is operably coupled to a client,

said client is communicatively coupled to a server, and

said server executes said first, said second and said third sets of instructions.

129. The computer program product of claim 128, wherein said second set of instructions comprises:

a first subset of instructions, executable on said computer system, configured to receive synchronization information, wherein

said data store is operably coupled to said server.

130. The computer program product of claim 129, wherein said second set of instructions comprises:

a second subset of instructions, executable on said computer system, configured to send said second data to said client; and

a third subset of instructions, executable on said computer system, configured to cause said client to store said second data in said local data cache.

131. The computer program product of claim 129, further comprising:

a fourth set of instructions, executable on said computer system, configured to receive a request for content.

132. The computer program product of claim 131, further comprising:

a fifth set of instructions, executable on said computer system, configured to generate said first validation information from authentication information available to said server.

133. The computer program product of claim 132, further comprising:

a sixth set of instructions, executable on said computer system, configured to send a response to said request for content, wherein

said response to said request for content comprises said first validation information.

134. The computer program product of claim 131, wherein said second set of instructions comprises:

a first subset of instructions, executable on said computer system, configured to receive synchronization information, wherein

said data store is operably coupled to said server, and

a response to said request for content from said server comprises said first validation information.

135. A apparatus comprising:

means for comparing first validation information and second validation information; and

means for synchronizing first data stored in a local data cache with second data stored in a data store, if said comparing indicates said synchronizing is needed.

136. The apparatus of claim 135, further comprising:

means for receiving said first validation information.

137. The apparatus of claim 136, wherein

said local data cache comprises said second validation information.

138. The apparatus of claim 136, wherein said means for synchronizing comprises:

means for deleting said first data from said local data cache; and

means for writing said second data to said local data cache.

139. The apparatus of claim 136, wherein said means for synchronizing comprises:

means for deleting said local data cache; and

means for writing a new local data cache.

140. The apparatus of claim 136, wherein

a client comprises said means for receiving said first validation information,

said client is communicatively coupled to said a server,

said means for synchronizing comprises means for sending synchronization information to said server, and

said data store is operably coupled to said server.

141. The apparatus of claim 140, further comprising:

means for storing said local data cache as a file in a directory structure of said client.

142. The apparatus of claim 140, further comprising:

means for storing said local data cache as a plurality of files in a directory structure of said client.

143. The apparatus of claim 142, wherein said means for synchronizing comprises:

means for deleting a one of said files; and

means for writing a new file, wherein said file is another of said files.

144. The apparatus of claim 140, wherein said means for synchronizing further comprises:

means for receiving said second data from said server; and

means for storing said second data in said local data cache.

145. The apparatus of claim 144, wherein said means for synchronizing further comprises:

means for causing said server to read said second data from said data store.

146. The apparatus of claim 136, further comprising:

means for causing a content server to generate said first validation information from authentication information available to said content server.

147. The apparatus of claim 146, further comprising:

means for sending a request for content to said content server.

148. The apparatus of claim 147, further comprising:

means for causing said content server to send a response to said request for content, wherein

said response to said request for content comprises said first validation information.

149. The apparatus of claim 147, wherein said means for synchronizing comprises:

means for sending said first synchronization information to a data server, wherein

said client is communicatively coupled said data server,

said data store is operably coupled to said data server, and

a response to said request for content from said content server comprises said first validation information.

150. The apparatus of claim 149, wherein said means for synchronizing further comprises:

means for receiving said second data from said data server; and

means for storing said second data in said local data cache.

151. The apparatus of claim 150, wherein said means for synchronizing further comprises:

means for causing said data server to read said second data from said data store.

152. The apparatus of claim 136, further comprising:

means for authenticating a user of said client, wherein

said means for authenticating is performed by an authentication server communicatively coupled to said client, and

said means for authenticating comprises

means for storing authentication information for said user in an authentication database operably coupled to said authentication server, if said authenticating is successful.

153. The apparatus of claim 152, further comprising:

means for sending a request for content to a content server, wherein said authentication server is communicatively coupled to said content server.

154. The apparatus of claim 153, further comprising:

means for causing said content server to send a response to said request for content, wherein

said response to said request for content comprises said first validation information.

155. The apparatus of claim 154, further comprising:

means for causing said authentication server to communicate said authentication information to said content server; and

means for causing said content server to generate said first validation information using said authentication information.

156. The apparatus of claim 155, wherein said means for synchronizing comprises:

means for sending said first synchronization information to a data server, wherein

said client is communicatively coupled said data server, and

said data store is operably coupled to said data server.

157. The apparatus of claim 136, wherein

said local data cache is operably coupled to a client, and

said client comprises said means for receiving, said means for comparing and said means for synchronizing.

158. The apparatus of claim 157, wherein said means for synchronizing comprises:

means for sending synchronization information to a server, wherein

said client is communicatively coupled said server, and

said data store is operably coupled to said server.

159. The apparatus of claim 157, wherein

said local data cache comprises said second validation information.

160. The apparatus of claim 159, further comprising:

means for sending a request for content to a content server.

161. The apparatus of claim 160, further comprising:

means for causing said content server to generate said first validation information from authentication information available to said content server.

162. The apparatus of claim 161, further comprising:

means for causing said content server to send a response to said request for content, wherein

said response to said request for content comprises said first validation information.

163. The apparatus of claim 160, wherein said means for synchronizing comprises:

means for sending said first synchronization information to a data server, wherein

said client is communicatively coupled said data server,

said data store is operably coupled to said data server, and

a response to said request for content from said content server comprises said first validation information.

164. The apparatus of claim 136, wherein

said local data cache is operably coupled to a client,

said client is communicatively coupled to a server, and

said server comprises said means for receiving, said means for comparing and said means for synchronizing.

165. The apparatus of claim 164, wherein said means for synchronizing comprises:

means for receiving synchronization information at said server, wherein

said data store is operably coupled to said server.

166. The apparatus of claim 165, wherein said means for synchronizing further comprises:

means for sending said second data to said client; and

means for causing said client to store said second data in said local data cache.

167. The apparatus of claim 165, further comprising:

means for receiving a request for content at said server.

168. The apparatus of claim 167, further comprising:

means for generating said first validation information from authentication information available to said content server.

169. The apparatus of claim 168, further comprising:

means for sending a response to said request for content, wherein

said response to said request for content comprises said first validation information.

170. The apparatus of claim 167, wherein said means for synchronizing comprises:

means for receiving said first synchronization information at said server, wherein

said data store is operably coupled to said server, and

a response to said request for content from said server comprises said first validation information.