System for changing a program stored in a terminal device and a terminal device used in the system

A terminal device, comprising:

• a program storage area that stores at least one to-be-used program transferred from a base station in response to a selection by a user to change an overall function of said terminal device;
• a program executing area that stores a main program and at least one application program, each said at least one application program being necessary for executing device functions of said terminal device and said main program controlling said at least one application program to provide an overall terminal device function selected by a terminal device user;
• a memory management table that stores data relative to which application programs are necessary for said overall terminal device functions and which application programs are unnecessary;
• a signal-receiving and -transmitting circuit for receiving and transmitting a signal to said base station;
• and
• a central processing unit which controls said program storage area, said program executing area, said memory management table, and said signal-receiving and -transmitting circuit,
• wherein a change of overall terminal device functions is achieved by adding any of one or more application programs necessary for a selected new overall terminal device function and a new main program for executing said selected new overall terminal device function, using the added one or more application programs, along with any application programs already stored in said terminal device for a previously-selected function that are also necessary for said selected new overall terminal device function and
• wherein said central processing unit causes said program storage area to transfer a to-be-used program to said program executing area with reference to said data stored in said memory management table, if a check sum of said program storage area is not coincident with a check sum of said program executing area.

A system for changing programs stored in a terminal device, said system comprising:

• a base station;
• a program-transferring device which transfers a to-be-used program to said base station, based on a request from a user to change a function of a terminal device;
• and
• a terminal device which downloads said to-be-used program from said program-transferring device through said base station, said terminal device including:
• a memory including:
• a program storage area to store said downloaded to-be-used program, according to a selection by a terminal device user;
• and
• a program executing area to store a program for executing said selected function;
• and
• a memory management table that stores data related to whether a program is necessary for said selected function, said data permitting:
• programs necessary for said selected function to be booted into said program executing area;
• programs not necessary for said selected function to be removed from said memory;
• and
• a function of said terminal device to be changed by downloading only program sections necessary to execute a newly selected function, in conjunction with program sections already stored in said terminal device for a previously-selected function,
• wherein said terminal device further includes a controller, said controller transferring said to-be-used program to said program storage area with reference to said data, if a check sum of said program executing area is not coincident with a check sum of said program storage area, and copying programs stored in said program storage area into said program executing area.

A system for changing programs stored in a terminal device, comprising:

• a base station;
• a program-transferring device which transfers a to-be-used program to said base station in response to a request from a terminal device user to select a function of a terminal device in said system;
• and
• a terminal device which downloads said to-be-used program from said program-transferring device through said base station, said terminal device including:
• a program storage area that stores said to-be-used program;
• a program executing area that stores programs to execute a selected function of said terminal device;
• and
• a memory management table that stores data designating whether programs are necessary to a function selected by a terminal device user, said data allowing programs for said selected function to be loaded into said program execution area and programs not necessary for said selected function to be removed from a memory of said terminal device, thereby allowing a change in function of said terminal device by adding only program sections necessary for said change in function, as viewed to be in conjunction with programs already stored in said terminal device for a previously-selected function;
• a signal-receiving and -transmitting circuit for receiving and transmitting a signal from or to said base station;
• and
• a central processing unit which controls an operation of said program storage area, said program executing area, said memory management table, and said signal-receiving and -transmitting circuit,
• wherein said central processing unit causes said program storage area to transfer said to-be-used program to said program executing area with reference to said data stored in said memory management table, if a check sum of said program storage area is not coincident with a check sum of said program executing area.

A method of changing programs stored in a terminal device including a memory that includes a program storage area to store a to-be-used program transferred from a base station, a program executing area including a plurality of programs, and a memory management table that stores data designating each of said plurality of programs stored in said program executing area as to be used or to be removed, the method comprising:

• calculating a check sum of said program storage area that includes the to-be-used program and a to-be-removed program;
• calculating a check sum of said program executing area;
• comparing said check sum of said program storage area to said check sum of said program executing area;
• and
• booting said to-be-used program from said program storage area to said program executing area in accordance with said data stored in said memory management table, if said check sum of said program storage area is not coincident with said check sum of said program executing area.