Abstract: Briefly, some embodiments of the invention provide, for example, devices, systems and methods for storage and access of computer files. A method in accordance with an embodiment of the invention may include, for example, receiving from a remote site a request to access a first file having a plurality of blocks, said request having a pre-defined format encapsulating an original request of a client of a synchronous client-server system and in accordance with a pre-defined file system; determining, for each of at least some of said plurality of blocks, a differential portion representing a difference between each said block and a corresponding block of a second file; and sending said differential portion to said remote site.