PURPOSE: To enable each subject to independently operate its information without using unnecessarily the storage capacity by copying the information and its related attribute information in response to the change required to the attribute information.
CONSTITUTION: When an attribute changing command is inputted for the change of the display state (attributes like colors and luminance, etc.) of a circle 72a to be shown on another subject or a screen layout 41a is inputted while a subject 40 like e screen layout is operating the information, the reference number 2 of the operating subject medium information 61a is decreased (down to 1) end stored in a medium information storing 6 as the medium information 61. Then the operating subject medium information 63 whose attribute is changed is copied for production of the information 61 which is stored in the area 6. The reference number of the copied information 63 is set at 1 and then the attribute information on the information 63 is changed to A4 from A2 based on the information inputted by the attribute changing command. Then the copied information is operated based on the attribute information A4.
SAITO MASAYUKI
TAKAGI HIROYUKI
HITACHI KEIYO ENG