Patent ID: 7120909

Claim:
A terminal device, comprising: a memory including: a program storage area to store at least two programs grouped into at least two groups with respect to overall functions of said terminal device, as supported by said programs, said at least two groups including categorization whether a program is necessary for a change of an overall function to be executed by said terminal device, said program storage area thereby including a to-be-used program and, optionally, a to-be-removed program, according to a selection by a terminal device user to change a current overall function of said terminal device to a new overall function; a program executing area to store programs for executing said new overall function; and a memory management table that stores data designating which of any programs in said program storage area are necessary for said new overall function, thereby allowing each said to-be-used program and said to-be-removed program to be identified for said new overall function and allowing said to-be-used program to contain only programs necessary to execute said new overall function, when used in combination with programs already stored in said terminal device for executing said current overall function; and a controller causing said to-be-used program to be transferred to said program executing area with reference to said data, if a check sum of said program storage area is not coincident with a check sum of said program executing area, wherein said data allows any of said to-be-removed program to be removed when said new overall function is activated.