An exemplary server includes a housing, a printed circuit board disposed in the housing, a power supply received in the housing, a hard disk drive assembly fixed in the housing and a connection device connected to the hard disk drive. The connection device includes a connector connected to the hard disk drive, an adapter connected to the hard disk drive, a power transferring line connecting the adapter to the power supply, and a data transferring line connecting the connector to the printed circuit board. The adapter has output pins and input pins for transferring power from the power supply to the hard disk drive. Capacitors and resistors are connected between the input pins and the output pins.