Abstract: A control method executed by a computer includes determining which one of a first virtual machine that executes a real-time process and a second virtual machine that executes a batch process a virtual machine being operated is, stopping the virtual machine being operated, when a process executed by the virtual machine being operated is finished and the virtual machine being operated is the second virtual machine, and maintaining operation of the virtual machine being operated, when the process executed by the virtual machine being operated is finished and the virtual machine being operated is the first virtual machine.

Abstract: A flatness measuring apparatus is adapted to measure the flatness of the surface of a plate-shaped object such as a disk in a non-contact fashion. A disk is removably held by a measuring table, with the projection of the measuring table engagedly received in a central through hole of the disk. A plurality of eddy current undulation sensors are arranged in a sensor head that is arranged so as to be able to linearly move back and forth along the measuring table. Said eddy current undulation sensors generate an eddy current in said disk and detect any undulation on the surface of said disk. A flatness map is produced for the surface of the disk based on a signal representing the position of the sensor head and on signals from the eddy current undulation sensors, and then is output to a display and/or a printer.