Patent ID: 6892255

Claim:
An operating system program rewriting method for use in a personal digital assistant having a storage device including at least: (i) a first memory area where an operating system program is stored, (ii) a position-information memory area where position-information indicating a storage location of the operating system program is written, and (iii) a second memory area where at least data of a user is stored, the operating system program rewriting method comprising: transferring the data of the user stored in the second memory area to a memory of a personal computer; making a copy of the operating system program stored in the first memory area and storing the copy of the operating system program in the second memory area; rewriting the position-information written in the position-information memory area so as to indicate a location in the second memory area where the copy of the operating system program has been stored; writing in the first memory area another operating system program transferred from the personal computer; rewriting the position-information so as to indicate a location in the first memory area where said another operating system program has been written; and returning the data of the user stored in the memory of the personal computer to the second memory area, after the position-information has been rewritten.