Abstract: A head/disk testing device including an air-bearing plate with which disk mounting and removal are simplified. The head/disk testing device including an air-bearing plate and a means with which the disk and air-bearing plate are moved away from one another so that the disk and air-bearing plate do not contact one another when a disk is being mounted or demounted.

Abstract: When a test pattern is output that shows that a program has shifted to a subroutine, a subroutine stay time measuring circuit starts counting a count value that shows a program stay time in the subroutine, and outputs return instruction data when the count value reaches a predetermined value. A sequence control circuit controls a program counter value so that the program returns to a call originating routine when the sequence control circuit receives the return instruction data and also when a test pattern that shows that the program returns from the subroutine to the call originating routine is output.