Apparatus and method for transmitting serial ATA information
A method and system are provided for transmitting SATA (serial advanced technology attachment) information. In an implementation, SATA commands are passed to an expander, rather than SCSI (Small Computer System Interface) commands. In an example implementation, SATA protocol elements are encapsulated into SAS (Serial Attached SCSI)-like frames and transmitted using the SSP (Serial SCSI protocol) and using SSP hardware.
1. A method of facilitating communications between a host device and a serial advanced technology attachment (SATA) target device over a serial attached small computer system interface (SAS) fabric, comprising:
translating, at the host device, a Small Computer System Interface (SCSI) command into a SATA command, wherein the SATA command is included in one or more SATA information units;
encapsulating, at the host device, the one or more SATA information units into a SAS frame to generate a modified SAS frame;
sending the modified SAS frame to an expander device using a Serial SCSI protocol (SSP);
decapsulating, at the expander device, the one or more SATA information units; and
transmitting the unencapsulated one or more SATA information units over a SATA connection to the SATA target device.
2. The method of claim 1 wherein the sending the modified SAS frame uses a SSP transport protocol but not a SATA transport protocol or a serial ATA tunneling protocol (STP).
3. The method of claim 1 wherein the sending the modified SAS frame to the expander device is performed without involving any SATA frames comprising SATA handshake communications.
4. A system comprising:
a host device comprising a host bus adapter configured to translate a Small Computer System Interface (SCSI) command into a serial advanced technology attachment (SATA) command, wherein the SATA command is included in one or more SATA information units, the host bus adapter further configured to encapsulate the one or more SATA information units into a serial attached SCSI (SAS) frame to generate a modified SAS frame, the host device configured to send the modified SAS frame using a Serial SCSI protocol (SSP); and
an expander device configured to receive the modified SAS frame using SSP, to decapsulate the one or more SATA information units, and to transmit the unencapsulated one or more SATA information units over a SATA connection to a SATA target device.
5. The system of claim 4 wherein the host device is configured to send the modified SAS frame using a SSP transport protocol but not a SATA transport protocol or a serial ATA tunneling protocol (STP).
6. The system of claim 4 wherein the expander device and the host bus adapter manage connections using native SSP protocol connection management.
7. The system of claim 4 wherein the host device is configured to send the modified SAS frame to the expander device without involving any SATA frames comprising SATA handshake communications.
8. The system of claim 4 wherein the host device is configured to send the modified SAS frame without using any serial ATA tunneling protocol (STP) specific primitives.
9. The system of claim 4 wherein the host bus adapter is configured to encapsulate the one or more SATA information units into the SAS frame using SAS frame types and headers.
10. The system of claim 4 wherein the one or more SATA information units comprises at least one SATA command information unit.
11. The method of claim 1 wherein the sending the modified SAS frame is performed without using any serial ATA tunneling protocol (STP) specific primitives.
12. The method of claim 1 wherein the encapsulating the one or more SATA information units into the SAS frame involves using SAS frame types and headers.
13. The method of claim 1 wherein the one or more SATA information units comprises at least one SATA command information unit.
14. An expander device for communicating information between a host device and a serial advanced technology attachment (SATA) target device, the expander device comprising:
a Serial Attached small computer system interface (SCSI) (SAS) port configured to receive a modified SAS frame using serial SCSI protocol (SSP), wherein the modified SAS frame comprises one or more SATA information units encapsulated into a SAS frame, wherein a SATA command is included in the one or more SATA information units, and wherein the SATA command was previously translated from a SCSI command at the host device;
a decapsulator for decapsulating the one or more SATA information units from the received modified SAS frame;
a SATA port for sending the one or more unencapsulated SATA information units to the SATA target device over a SATA connection.
15. The expander device of claim 14 configured to receive the modified SAS frame using a SSP transport protocol but not a SATA transport protocol or a serial ATA tunneling protocol (STP).
16. The expander device of claim 14 configured to receive the modified SAS frame from a host device without involving any SATA frames comprising SATA handshake communications.
17. The expander device of claim 14 configured to receive the modified SAS frame from a host device without the use of any serial ATA tunneling protocol (STP) specific primitives.