Patent ID: 7366641

Claim:
A disk drive connectable to a host through an interconnect, the disk drive comprising: a disk, an interconnect connectable to a host; a signal measurement circuit to measure voltage amplitudes of signals from the host; and a processor for controlling operations in the disk drive including writing and reading data to and from the disk, the processor being coupled to the signal measurement circuit, the processor under the control of a program in conjunction with the signal measurement circuit to: measure an amplitude of the voltage of a signal from the host during a first speed negotiation process; and determine if the amplitude of the signal from the host is above a pre-determined amplitude for the disk drive and, if so, command the disk drive to transmit signals to the host at the measured amplitude of the first speed negotiation process; wherein, if the amplitude is below the pre-determined amplitude for the disk drive, a second speed negotiation process is forced using a lower frequency signal from the host.