Method and apparatus for supporting access of a serial ATA storage device by multiple hosts with separate host adapters

• US 20050251588A1
• Filed: 03/26/2002
• Published: 11/10/2005
• Est. Priority Date: 01/18/2002
• Status: Active Grant

• Current Assignee: Resilient
• Original Assignee: GENX Systems Incorporated
• Inventors: Rydhan, Mohammad Farooq, Chang, Yee-Hsiang Sean, Hoch, John Stuart
• Granted Patent: US 7,552,289 B2
• Time in Patent Office: Days
• US Class Current: 710/5
• CPC Class Codes: G06F 1/3221 of disk drive devices
• CPC Class Codes: G06F 13/4022 using switching circuits, e.g. switching matrix, connection or expansion network G06F13/4009 takes precedence
• CPC Class Codes: G06F 3/0617 in relation to availability
• CPC Class Codes: G06F 3/0635 by changing the path, e.g. traffic rerouting, path reconfiguration
• CPC Class Codes: G06F 3/0658 Controller construction arrangements
• CPC Class Codes: G06F 3/0674 Disk device
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

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.

Claims

1. An adapter unit operative to support access of a Serial Advanced Technology Attachment (SATA) storage device by a plurality of hosts associated with separate host adapters, comprising:

a multiplexer configured to receive a plurality of sets of communication signals, one signal set for each of a plurality of host adapters, and to select one of the plurality of signal sets based on a control signal and couple the selected signal set to a multiplexer output; and

an arbiter operatively coupled to the multiplexer and configured to receive requests from the plurality of hosts to access the SATA storage device, select a particular requesting host to grant access, and provide the control signal indicative of the host granted access to the SATA storage device.

2. The adapter unit of claim 1, wherein the host adapter for the granted host and the SATA storage device are each placed in a proper state, prior to a read or write access, via an exchange of a handshake signal.

3. The adapter unit of claim 2, wherein the host adapter for the granted host and the SATA storage device are each placed in a PHY READY power management state, prior to the read or write access, via an exchange of a COMWAKE signal.

4. The adapter unit of claim 3, wherein the host adapter for the granted host and the SATA storage device are each placed in a PARTIAL power management state after the read or write access.

5. The adapter unit of claim 1, wherein the multiplexer is operative to receive two sets of communication signals from two host adapters.

6. The adapter unit of claim 1, wherein the multiplexer includes a set of switches for each set of communication signals.

7. The adapter unit of claim 6, wherein each switch is implemented with a CMOS switch.

8. The adapter unit of claim 1, wherein the arbiter includes

a state machine configured to maintain a list of hosts not allowed to be granted access to the SATA storage device.

9. The adapter unit of claim 1, wherein the arbiter includes

a state machine configured to maintain a list of hosts allowed to be granted access to the SATA storage device.

10. The adapter unit of claim 8, wherein the arbiter includes

a timer configured to provide timing information for the state machine.

11. The adapter unit of claim 8, wherein a host granted access for a particular maximum time limit is placed on the list of hosts not allowed to be granted access to the SATA storage device.

12. The adapter unit of claim 8, wherein a host is removed from the list of hosts not allowed to be granted access to the SATA storage device upon negating its grant request.

13. The adapter unit of claim 1, wherein the arbiter communicates with each of the plurality of hosts via a respective set of control signals.

14. The adapter unit of claim 13, wherein each control signal set includes a request signal and a grant signal.

15. The adapter unit of claim 1 and implemented on a circuit card.

16. An adapter unit operative to support access of a Serial Advanced Technology Attachment (SATA) device by a plurality of hosts associated with separate host adapters, and configured to

receive requests from the plurality of hosts to access the SATA device;

select a particular requesting host to grant access;

receive a plurality of sets of communication signals, one signal set for each of a plurality of host adapters;

select, from among the plurality of signal sets, a signal set corresponding to the host granted access; and

couple the selected signal set to an output of the adapter unit.

17. An adapter unit operative to support access of a Serial Advanced Technology Attachment (SATA) storage device by a plurality of hosts associated with separate host adapters, comprising:

a multiplexer configured to receive a plurality of sets of communication signals, one signal set for each of a plurality of host adapters, and to select one of the plurality of signal sets based on a control signal and couple the selected signal set to a multiplexer output; and

an arbiter operatively coupled to the multiplexer and configured to receive requests from the plurality of hosts to access the SATA storage device, select a particular requesting host to grant access, and provide the control signal indicative of the host granted access to the SATA storage device, and

wherein the host adapter for the granted host and the SATA storage device are each placed in a PHY READY power management state, prior to a read or write access, via an exchange of a COMWAKE signal, and are each placed in a PARTIAL power management state after the read or write access.

18. A method of supporting access to a Serial Advanced Technology Attachment (SATA) storage device by a plurality of hosts associated with separate host adapters, comprising:

receiving requests from the plurality of hosts to access the SATA storage device;

selecting a particular requesting host to grant access;

providing a control signal indicative of the host granted access to the SATA storage device;

receiving a plurality of sets of communication signals, one signal set for each of a plurality of host adapters;

selecting one of the plurality of signal sets based on the control signal; and

coupling the selected signal set to the SATA storage device.

19. The method of claim 18, further comprising:

placing the host adapter for the granted host and the SATA storage device in a PHY READY power management state, prior to a read or write access, via an exchange of a COMWAKE signal on the selected signal set.

20. The method of claim 19, further comprising:

placing the host adapter for the granted host and the SATA storage device in a PARTIAL power management state after the read or write access.

21. The method of claim 18, further comprising:

maintaining a timer for the host granted access to the SATA storage device; and

removing the grant from the host if access has been granted for a particular maximum time limit.

22. The method of claim 18, wherein the plurality of hosts is granted access to the SATA storage device based on a fair arbitration scheme.