VIDEO-ON-DEMAND SYSTEM, VIDEO CLIENT, VIDEO SERVER, STORAGE MEDIUM WITH VIDEO CLIENT SOFTWARE STORED THEREIN, AND STORAGE MEDIUM WITH VIDEO SERVER SOFTWARE STORED THEREIN

摘要

PROBLEM TO BE SOLVED: To more surely prevent illegal data backup than by a means such as an ID or recognition of password. SOLUTION: A video client 3 reads volume serial number of a hard disk stored in an OS by a volume serial number read means 31 and transmits them to a video server 2, when he requests data backup of a video server 2, The video server 2 stores the volume serial numbers that allow the data backup in a volume serial number management table 23 in advance. volume serial number management means 21 collates the volume serial number from the video client side to contents in the volume serial number management table 23 by a volume serial number collation means 22 and decides the possibility of to performing data backup.