In a client/server environment, a method and means for reducing the storage requirement in the backup subsystem and further reducing the load on the transmission bandwidth where base files are maintained on the server in a segmented compressed format. When a file is modified on the client, the ...http://www.google.com.tw/patents/US5813017?utm_source=gb-gplus-share專利 US5813017 - System and method for reducing storage requirement in backup subsystems utilizing segmented compression and differencing 
