Synchronization of host computers and handheld remote computers

A method for communicating synchronization information between at least one handheld client computer and a host computer, comprising the steps of:

• providing a host computer having a set of host databases stored therein;
• providing a handheld client computer having a set of client databases stored therein and database/record change-indicators corresponding to those client databases/records which have been changed since the last prior synchronization;
• providing a data channel between the host computer and the handheld client computer;
• establishing a data-link between the host computer and the handheld client computer through the data channel;
• transferring from the handheld client computer to a cache in the host computer a skeletal snapshot of the client databases, wherein the skeletal snapshot includes at least one state indicator selected from the group consisting of the state of the remote databases/records, change-indicators and time-stamps, unique identifiers, and database/record indices in an ordered list;
• determining an up-transfer list of client records to be transferred from the client computer to the host computer;
• up-transferring from the handheld client computer to the cache of the host computer the records on the up-transfer list and associating the up-transferred records on the up-transfer list with the skeletal snapshot, so as to be available to a record synchronization operation;
• receiving from the record synchronization operation a set of updated host records to be down-transferred and requests to delete client records;
• and
• down-transferring from the host computer to the handheld client computer the set of updated host records to be down transferred, and also storing the updated host records in the cache associated with the skeletal snapshot, the steps of up-transferring and down-transferring being accomplished in a full-duplex, asynchronous manner.