VEHICLE ELECTRONIC CONTROL SYSTEM, FILE TRANSFER CONTROL METHOD, COMPUTER PROGRAM PRODUCT AND DATA STRUCTURE OF SPECIFICATION DATA

In a vehicle electronic control system, a second device includes a transfer target file specifying unit that is configured to specify a file, as a transfer target file, including update data to be written into a third device, a first data size specifying unit that is configured to specify a first data size to acquire the transfer target file specified by the transfer target file specifying unit, and an update data distribution unit that is configured to distribute the update data to the third device using a plurality of divided files transferred from the first device. The first device includes an update data transfer unit that is configured to transfer the update data by dividing the transfer target file specified by the transfer target file specifying unit into the plurality of divided files according to the first data size specified by the first data size specifying unit, and transferring the plurality of divided files to the second device.