An adapter unit operative to support access of an SATA storage device by a plurality of hosts associated with separate host adapters. The adapter unit includes a multiplexer coupled to an arbiter. The multiplexer receives a plurality of sets of communication signals, one signal set for each host adapter. The multiplexer then selects one of the signal sets based on a control signal and couples the selected signal set to its output. The arbiter receives requests from the hosts to access the SATA storage device, selects a particular requesting host, and provides the control signal indicative of the specific host granted access. The host adapter for the granted host and the SATA storage device are placed in a PHY READY power management state, prior to a read or write access, and are placed in a PARTIAL power management state after the read or write access.