1. A magnetic disk apparatus having a patrol function that uses a patrol region in the disk to determine the presence/absence of the need of preventive maintenance, comprising: a data pattern generation section that generates a data pattern for detecting crosstalk in hardware equipment around the disk; a command execution section that executes a write command or read command corresponding to the data pattern generated by the data pattern generation section; and a crosstalk determination/detection section that determines/detects the crosstalk based on the command execution result obtained by the command execution section.