A process, apparatus, and system are disclosed for inhibiting erroneous control signals due to disruptive electromagnetic signals. In one embodiment, the invention prevents erroneous information writing in a recording device under the effect of background electromagnetic waves. A conductor pattern is formed on a printed wiring board on which wiring constituting a control circuit of a hard disk drive is formed. Background electromagnetic waves are detected by an electromagnetic wave detection circuit. In the case where an electromagnetic wave signal detected by the electromagnetic wave detection circuit exceeds a predetermined power, voltage, or current threshold, a write gate signal is turned off to inhibit a potential write operation.