Disk array controller and system with automated detection and control of both ATA and SCSI disk drives

Abstract

A disk array controller detects whether each drive it is connected to is an ATA drive or a SCSI drive, and communicates with that disk drive using the corresponding protocol. Preferably, the disk array controller supports both the Serial ATA interface specification and the Serial Attached SCSI interface specification, allowing either or both types of disk drives to be included within a RAID or other disk array configuration. The disk array controller may be incorporated into a storage server having hot swap drive carriers that accommodate both types of disk drives.

1 . (canceled)  
     
     
         2 . A disk array controller that supports mixing and matching of Serial ATA (SATA) and Serial Attached SCSI (SAS) disk drives, the disk array controller comprising: 
 a plurality of ports for connecting disk drives to the disk array controller;    a plurality of controllers for controlling said disk drives, each controller being capable of detecting whether a disk drive to which it is connected is a SATA disk drive or a SAS disk drive, and being capable of communicating with the disk drive using either a SATA protocol or a SAS protocol; and    a processor which communicates with the plurality of controllers over a bus to initiate transfers of data to and from the disk drives;    wherein the disk array controller is capable of operating the plurality of disk drives as a disk array that includes a combination of SAS and SATA disk drives.    
     
     
         3 . A disk array controller as in  claim 2 , wherein each controller is configured to communicate with a disk drive during an initialization phase to determine whether it is a SAS disk drive versus a SATA disk drive.  
     
     
         4 . A disk array controller as in  claim 2 , wherein each controller is configured to adjust at least one physical layer parameter to account for a difference between SAS and SATA disk drives.  
     
     
         5 . A disk array controller as in  claim 2 , wherein the processor communicates with the controllers to determine whether each of the disk drives is a SATA disk drive or a SAS disk drive.  
     
     
         6 . A disk array controller as in  claim 2 , further comprising an input/output (I/O) bus used to transfer input/output data associated with disk drive operations, wherein the disk array controller uses a first bus protocol on the I/O bus if the disk drives consist of SATA disk drives, and uses a second bus protocol on the I/O bus if the disk drives consist of SAS disk drives.  
     
     
         7 . A disk array controller as in  claim 6 , wherein the disk array controller uses a third bus protocol on the I/O bus if the plurality of disk drives include both SATA disk drives and SAS disk drives.  
     
     
         8 . A method of communicating with a disk drive, the method comprising: 
 during an initialization phase, communicating with the disk drive over a connector to determine whether the disk drive is a Serial Advanced Technology Attachment (SATA) disk drive versus a Serial Attached Small Computer System Interface (SAS) disk drive;    based on an outcome of the determination, selecting at least one physical layer parameter to be used to communicate with the disk drive so as to account for a difference between physical layer interfaces of SATA and SAS disk drives; and    communicating with the disk drive over said connector using the selected physical layer parameter.    
     
     
         9 . The method of  claim 8 , wherein selecting at least one physical layer parameter comprises controlling a programmable driver of a physical layer circuit.  
     
     
         10 . The method of  claim 8 , further comprising selecting between an ATA protocol engine and a SCSI protocol engine based on whether the disk drive is detected to be a SATA disk drive versus a SAS disk drive.  
     
     
         11 . The method of  claim 8 , wherein the method is performed by a controller that communicates with the disk drive over the connector.  
     
     
         12 . The method of  claim 8 , wherein the method is performed by an automated circuit of a controller that communicates with the disk drive.  
     
     
         13 . A controller that implements the method of  claim 8 .  
     
     
         14 . A disk array controller that implements the method of  claim 8  separately for each of a plurality of disk drives of a disk array.  
     
     
         15 . The method of  claim 8 , wherein the connector comprises a cable.  
     
     
         16 . A controller, comprising: 
 a detection circuit capable of detecting a type of a disk drive that is connected to the controller, wherein the detection circuit is capable of distinguishing between a Serial Advanced Technology Attachment (SATA) disk drive and a Serial Attached Small Computer System Interface (SAS) disk drive;    an ATA protocol engine that is used to communicate with the disk drive if the disk drive is determined by the detection circuit to be a SATA disk drive; and    a SCSI protocol engine that is used to communicate with the disk drive if the disk drive is determined by the detection circuit to be a SAS disk drive.    
     
     
         17 . A controller as in  claim 16 , further comprising a physical layer circuit that is responsive to the detection circuit by adjusting at least one physical layer parameter used to communicate with the disk drive so as to account for a difference between SATA and SAS disk drives.  
     
     
         18 . A controller as in  claim 17 , wherein the physical layer circuit comprises a set of programmable drivers that are used to account for said difference.  
     
     
         19 . A controller as in  claim 16 , wherein the detection circuit is capable of determining whether the disk drive is a SATA disk drive versus a SAS disk drive based on communications between the controller and the disk drive.  
     
     
         20 . A controller as in  claim 16 , further comprising an ATA link layer circuit that is used to communicate with the disk drive if the disk drive is determined by the detection circuit to be a SATA disk drive; and a SCSI link layer circuit that is used to communicate with the disk drive if the disk drive is determined by the detection circuit to be a SAS disk drive  
     
     
         21 . A controller as in  claim 16 , further comprising a configurable first-in-first-out (FIFO) buffer the buffers input/output data associated with disk drive operations, wherein the controller configures the FIFO buffer differently depending upon whether the disk drive is a SATA disk drive versus a SAS disk drive.