Patent ID: 8793374

Claim:
A method of permitting simultaneous use of a file by two or more computers over a public network, said method comprising: initiating a first firewall compliant connection between a local computer located behind a first firewall element and a public server; storing the file locally in a local storage device associated with the local computer; providing access to the file by a remote computer connectable to the local computer via the public server over the public network, wherein the remote computer is located behind a second firewall element and connected to the public server via a second firewall compliant connection; storing the file in a remote storage device locally associated with the remote computer; and synchronizing versions of the file contained on the remote storage device with the local device by transmitting over the network at least one of Delta files and Inverse Delta files between the remote storage device and the local storage device, wherein the versions of the file are synchronized and are updated each time a new version of the file is saved at the local computer or remote computer, as long as the local and remote computers are connected in an active subscription.