An improved remote protocol enables efficient and reliable updating of files on a remote server. A gather-copy extension to a remote protocol enables a client to instruct a server to gather portions of data from an existing source file on the server and to copy those portions of data to appropriate offsets within a new destination file on the server. The gather-copy extension thus enables the client to leave blank locations in the destination file into which the client can write new data during a file update. The gather-copy extension also enables the client to effectively delete portions of the source file by not copying them from the source file to the destination file. File updates can therefore be made without having to transfer the entire file from the client to the server.