System for preventing the use of an unauthorized external memory

A system for preventing an unauthorized external memory unit from being used in an information processing system including an external memory unit being attachable or detachable to or from said information processing system, said information processing system being capable of displaying a predetermined image in accordance with a program stored in the external memory unit when the external memory is attached thereto, comprising:

• said information processing system including central processing means for executing program instructions and internal memory means for storing first character data;
• said external memory unit including external memory means for storing second character data;
• memory bank selecting means for enabling access by said central processing means to one of said external memory unit and said internal memory means, said memory bank selecting means including first means for enabling access to said first character data stored in said internal memory means, and
• second means for enabling access to said second character data stored in said external memory unit;
• determining means for determining whether said first character data and said second character data have a predetermined relationship;
• display means for displaying an image;
• means for controlling said display means to display character data in accordance with the second character data stored in said external memory unit prior to said determining means determining whether said predetermined relationship exists;
• said memory bank selecting means including third means for allowing said central processing means access to said external memory unit when it is determined that said first character data and said second character data have said predetermined relationship;
• and
• inhibiting means for inhibiting said central processing means from accessing said external memory unit when it is determined that said first character data and said second character data do not have said predetermined relationship.

A system for preventing an unauthorized external memory unit from being used in a game machine which utilizes a removable external memory unit including external memory means for storing a game program, said system comprising:

• main game processing means for executing said game program;
• internal memory means coupled to said main game processing means for storing first character data and an authenticating program;
• said removable external memory unit including external memory means for storing said game program, second character data, auxiliary data, and a predetermined value which has a predetermined mathematical relation to said auxiliary data;
• a display means for displaying an image;
• said main game processing means including:
• a memory select circuit for enabling one of said external memory means and said internal memory means,
• first means for comparing said first character data with said second character data and for generating a first signal if a predetermined relationship exists between said first character data and said second character data;
• means for controlling said display means to display said second character data prior to said first means for comparing determining whether said predetermined relationship exists;
• means responsive to said first signal for performing a predetermined calculation using said auxiliary data;
• and
• second means for comparing the results of said predetermined calculation with said predetermined value;
• wherein said memory select circuit includes means for enabling said game program to be executed when said first signal is generated and if the results of said predetermined calculation has a predetermined relationship with said predetermined value.

A method for preventing an unauthorized external memory unit from being used in a hand-held game machine having a game processing means for executing a game program and a removable external memory unit having an external memory means for storing said game program, said method comprising the steps of:

• storing first character data in an internal memory means coupled to said main game processing means;
• storing second character data, predetermined auxiliary data, and a predetermined value which has a predetermined mathematical relation to said auxiliary data in said removable external memory unit;
• accessing said first character data and said second character data in response to enable signals generated by a memory selecting circuit;
• comparing said first character data with said second character data and generating a first signal if a predetermined relationship exists between said first character data and said second character data;
• displaying said second character data prior to said comparing step determining whether said predetermined relationship exists;
• performing in response to said first signal a predetermined calculation using said auxiliary data;
• comparing the results of said predetermined calculation with said predetermined value;
• providing a predetermined authenticity indicating signal to said memory select circuit to thereby enable said game program to be executed by said game processing means if said first signal is generated and if the results of said predetermined calculation has a predetermined relationship with said predetermined value.