PURPOSE: To make the preparation of data easy, by limiting a protection field in the hexadecimal notation form mode without taking inputted character strings as the protection field, through the input of the first character train from a keyboard in the 8-alphanumerical mode.

CONSTITUTION: When characters are inputted and displayed on a display device 2 from a keyboard 3 in the full screen optional (FSQ) function of edition instruction of a time sharing system (TSS), output data from a CPU1 is formed into attribute character data 4-1W4-5, 8-alphanumeric (CHAR) modes 5-1W5-3, and hexadecimal notation form HEX modes 6-1W6-2. When the item is the CHAR modes 5-1W5-3, character data 4-1, 4-3, 4-5 are defined as nonprotection fields, and when the hexadecimal form modes 6-1W6-2, the characters 4-2, 4-4 are defined as protection fields to prepare data easily.