col. 4, ln 33-49: Referring to FIGS. 1a and 1b, a remote computer 110 is coupled to a communication server computer 180 through one or more paths through a communication network infrastructure made up of various telephone and data networks. Remote computer 110 is a lap-top, general-purpose computer, but could also be one of a variety of personal digital assistants (PDAs), or a specialpurpose device such as an enhanced cellular telephone or paging receiver. Communication server computer 180 is a general purpose computer that is coupled to an application and database server 210 over a high-speed local computer network (local area network, LAN) 176, communicating at rates of 1-10 kb/s or higher. Remote computer 110 communicates with server computer 180 over one or more of a variety of communication paths through the communication network infrastructure. These paths exhibit various communication characteristics. col. 9, ln 33-63: In the case of electronic mail, agent module 332 is a mail agent. The mail agent performs one or more of the following functions. Periodically, the mail agent queries server application 362 to determine whether new mail has been received for a particular remote user. The server application maintains a database 364, in this case a database of mail messages. If the server application determines that unread mail is stored in database 364, this unread mail is provided to the mail agent. The mail agent determines whether the received mail should be forwarded to the remote computer. This decision may be based on a variety of factors, including the sender or other information in the message header, the length of the message, or information related to attachments to the message. Having decided to forward a message to a remote computer, the mail agent constructs a message including the mail message and addressed by name to the remote computer and the remote mail application, and then provides the message to message router 334. At the remote computer, a standard application 312 is used to access electronic mail. A corresponding application hook 314 has previously registered itself with transaction layer 318 with the name of the remote mail application. This application hook receives the message sent by the mail agent, extracts the mail message and provides the mail message to the standard mail application by writing the mail message in a shared directory of a file system on the permanent storage of the remote computer. Other methods of communication between the application hook and the standard application may also be used, depending on the standard interface supported by the application. col. 10, ln 47-53: In addition to electronic mail, similar cooperating application hook and agent modules support data access and partial synchronization of personal information databases, for example containing a personal calendar and address book. In addition, custom applications may provide access to a database, such as an inventory database for a mobile inventory control application.