Abstract:
It is determined whether a storage device that is coupled to a serial attached small computer systems interface (“SAS”) interface is a SAS storage device or a serial attached advanced technology attachment (“SATA”) storage device.

Description:
BACKGROUND  
       [0001]     The description herein relates to information handling systems having serial attached small computer systems interface (“SAS”) controllers.  
         [0002]     As the value and use of information continue to increase, individuals and businesses seek additional ways to process and store information. One option available to users is information handling systems. An information handling system (“IHS”) generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems.  
         [0003]     Serial attached small computer systems interface (“SAS”) and serial advanced technology attachment (“SATA”) storage devices (e.g., disk drives) are both capable of being coupled to a SAS interface (e.g., a “connector”). For example, a SAS controller with a SAS interface is capable of being coupled to either a SAS disk drive or a SATA disk drive via the same interface. Such compatibility may cause various problems such as a user undesirably or inadvertently connecting to a SAS controller, a SATA disk drive instead of a SAS disk drive, and vice versa.  
         [0004]     What is needed is a method and an IHS without the disadvantages discussed above.  
       SUMMARY  
       [0005]     Accordingly, it is determined whether a storage device that is coupled to a serial attached small computer systems interface (“SAS”) interface is a SAS storage device or a serial attached advanced technology attachment (“SATA”) storage device. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0006]      FIG. 1  is a block diagram of an information handling system, according to the illustrative embodiment.  
         [0007]      FIG. 2  is a block diagram of a storage enclosure, accordingly to the illustrative embodiment.  
         [0008]      FIG. 3  is a block diagram illustrating an interface (e.g., connector) that is representative of one of the interfaces of  FIG. 2 .  
         [0009]      FIG. 4  is a block diagram of a SAS storage device, including its interface, according to the illustrative embodiment.  
         [0010]      FIG. 5  is a block diagram of a SATA storage device, including its interface, according to the illustrative embodiment. 
     
    
     DETAILED DESCRIPTION  
       [0011]     For purposes of this disclosure, an information handling system (“IHS”) includes any instrumentality or aggregate of instrumentalities operable to compute, classify, process, transmit, receive, retrieve, originate, switch, store, display, manifest, detect, record, reproduce, handle, or utilize any form of information, intelligence, or data for business, scientific, control, or other purposes. For example, an information handling system may be a personal computer, a server computer, a storage enclosure, a network storage device, or any other suitable device and may vary in size, shape, performance, functionality, and price. The information handling system may include random access memory (RAM), one or more processing resources such as a central processing unit (CPU) or hardware or software control logic, ROM, and/or other types of nonvolatile memory. Additional components of the information handling system may include one or more disk drives, one or more network ports for communicating with external devices as well as various input and output (I/O) devices, such as a keyboard, a mouse, and a video display. The information handling system may also include one or more buses operable to transmit communications between the various hardware components.  
         [0012]      FIG. 1  is a block diagram of an IHS indicated generally at  100 , according to the illustrative embodiment. The IHS  100  includes a processor  105  (e.g., an Intel Pentium series processor). An Intel Hub Architecture (IHA) chipset  110  provides the IHS  100  with graphics/memory controller hub functions and I/O functions. More specifically, the IHA chipset  110  acts as a host controller which communicates with a video controller  125  coupled thereto. A display device  130  is coupled to the video controller  125 .  
         [0013]     The chipset  110  further acts as a controller for main memory  115  which is coupled thereto. The chipset  110  also acts as an input/output (“I/O”) controller hub (ICH) which performs I/O functions. A USB controller  170  is coupled to chipset  110  so that devices such as a peripheral device  175  can be connected to the chipset  110  and the processor  105 . Examples of the peripheral device  175  include printers, cameras, scanners, audio players, and other suitable devices. Although the peripheral device  175  communicates with the IHS  100  via a USB interface in the illustrative embodiment, in other embodiments, the peripheral device  175  communicates with the IHS  100  via another type of interface such as serial, parallel, FireWire, and/or any other suitable connection interface. A system basic input-output system (“BIOS”)  140  is coupled to chipset  110  as shown. The BIOS  140  is stored in CMOS or FLASH memory so that it is nonvolatile.  
         [0014]     A local area network (LAN) controller  145 , alternatively called a network interface controller (NIC), is coupled to the chipset  110  to facilitate connection of the IHS  100  to other IHSs. A media driver controller  150  is coupled to chipset  110  so that devices such as media drives  155  can be connected to the chipset  110  and the processor  105 . Examples of the media devices  155  capable of being coupled to the media controller  150  include CD-ROM drives, DVD drives, hard disk drives and other fixed or removable media drives. An expansion bus  120 , such as a peripheral component interconnect (PCI) bus, PCI express bus is coupled to the chipset  110  as shown. Via the expansion bus  120 , a storage enclosure controller (e.g., a host bus adapter)  122  is also coupled to the chipset  110 .  
         [0015]     In the illustrative embodiment, the IHS  100  is a server. For providing the IHS  100  with storage capacity, a storage enclosure is coupled to the IHS  100  via the controller  122 . Accordingly,  FIG. 2  is a block diagram of a storage enclosure  200 , accordingly to the illustrative embodiment.  
         [0016]     The storage enclosure  200  includes controller cards  202  and  204 . Each of the controller cards  202  and  204  includes expanders. For example, the controller card  202  includes expanders  206 ,  208 ,  210 , and the controller  204  includes expanders  212 ,  214 , and  216 . Via one or more of the expanders  206 ,  208 ,  210 ,  212 ,  214 , or  216 , one or more storage devices (e.g., SAS drives or SATA drives) are capable of being coupled to the controller card  202 .  
         [0017]     Within each of the controller cards  202  and  204 , one or more of the expanders are capable of operating as an interface between the controller  122  and other expanders. For example, within the controller card  202 , the expander  206  is an interface between the controller  122  and the other expanders  208  and  210 .  
         [0018]     The enclosure  200  also includes a back pane  218 , which includes interfaces  220 ,  222 ,  224 , and  226 . Via the interfaces  220 ,  222 ,  224 , and  226 , one or more SAS drives and/or SATA drives are capable of being coupled to one or more of the expanders included by the controller cards  202  and  204 . Accordingly, the enclosure  200  includes SAS/SATA storage devices  228 ,  230 ,  232 , and  234 , which are respectively coupled to the expanders  208 ,  220 ,  214 , and  216  via the interfaces  220 ,  222 ,  224 , and  226 .  
         [0019]     Although  FIG. 2  depicts the two controller cards  202  and  204 , the enclosure  200  may include additional controller cards which are substantially identical to the controller cards  202  and  204 , or include fewer controller cards. Similarly, although each of the controller cards is depicted as including three expanders, each of the controller card may include additional expanders that are substantially identical to the expanders depicted in  FIG. 2 , or fewer expanders.  
         [0020]      FIG. 3  is a block diagram illustrating an interface (e.g., connector), indicated at  300 , that is representative of one of the interfaces  220 ,  222 ,  224 , or  226  of  FIG. 2 . The interface  300  is a SAS interface, via which, a SAS storage device or a SATA storage device is capable of being coupled to an expander (e.g., one of the expanders of  FIG. 2 ) or another suitable device such as a SAS controller.  
         [0021]     The interface  300  includes a first port (e.g., port A)  302  and a second port (e.g., port B)  304 . Each of the ports  302  and  304  includes one or more transmit (“TX”) wires (e.g., “pins”), receive (“RX”) wires, and ground (“GND”) wires. For example, the port  302  includes GND pins  306 ,  312 , and  318 . The port  302  also includes TX pins  308  and  310 . Moreover, the port  302  includes RX pins  314  and  316 .  
         [0022]     Similar to the port  302 , the port  304  includes GND pins  320 ,  326 , and  332 , TX pins  322  and  324 , and RX pins  328  and  330 . The GND pin  332  is coupled to a detection circuit, indicated generally at  334 , that detects whether a SAS storage device or a SATA storage device is coupled to the interface  300 . The detection circuit  334  includes a resistor (e.g., a “pull-up” resistor)  336 . In the illustrative embodiment, the pull-up resistor  336  is an approximately 4.7 kilo-ohm pull-up resistor. The detection circuit  334  also includes a capacitor  338 . In one example, the capacitor  338  is an approximately 1 uF capacitor. Each of the pull-up resistor  336  and the capacitor  338  is coupled to the GND pin  332 .  
         [0023]     The detection circuit  334  is coupled to a voltage source  340  via the pull up resistor  334 . In the illustrative embodiment, voltage supplied by the voltage source  340  is approximately 5 volts. Also, the detection circuit  334  is coupled to a logic device  342  (e.g., a processor or a complex programmable logic device (“CPLD”), a field programmable gate array (“FPGA”) or a comparator circuit). The logic device  342  is also coupled to the GND pin  332 . In at least one alternative embodiment, the detection circuit  336  includes the logic device  342 .  
         [0024]      FIG. 4  is a block diagram of a SAS storage device  400 , including its interface, according to the illustrative embodiment. The SAS storage device  400  is capable of being coupled to an expander (e.g., one of the expanders of  FIG. 2 ) via an interface, such as the interface  300  of  FIG. 3 . For example, the storage device  400  includes a first port (e.g., port A)  402  and a second port (e.g., port B)  404 , each of which is respectively capable of being coupled the port  302  and the port  304  of  FIG. 3 .  
         [0025]     Each of the ports  402  and  404  includes one or more GND, TX, and RX pins. For example, the port  402  includes GND pins  406 ,  412 , and  418 , TX pins  408  and  410 , and RX pins  414  and  416 . The port  404  includes GND pins  420 ,  426 , and  432 , TX pins  422  and  424 , and RX pins  428  and  430 .  
         [0026]      FIG. 5  is a block diagram of a SATA storage device  500 , including its interface, according to the illustrative embodiment. Similar to the SAS storage device  400 , the SATA storage device  500  is capable of being coupled to an expander via an interface, such as the interface  300  of  FIG. 3 . However, the SATA storage device  500  couples to the interface  300  via one of the ports  302  and  304 . In the illustrative embodiment, the SATA storage device  500  couples to the interface  300  via the port  302  (e.g., port A). Accordingly, the SATA storage device  500  includes a port  502 , which is capable of being coupled to the port  302  of  FIG. 3 . Similar to the port  402  of  FIG. 4 , the port  302  includes GND pins  504 ,  510 , and  516 , TX pins  506  and  508 , and RX pins  512  and  514 .  
         [0027]     As discussed above, the detection circuit  334  determines (e.g., detects) whether a SAS storage device or a SATA storage device is coupled to the interface  300 . In one example, the detection circuit  334  makes such determination by determining whether an SAS storage device is coupled to the interface  300 . For example, if the detection circuit  334  determines that a SAS storage device is not coupled to the interface  300 , the detection circuit  334  determines that a SATA storage device is coupled to the interface  300 .  
         [0028]     In one embodiment, the detection circuit  334  determines whether a storage device that is coupled to the interface  300  is a SAS storage device or a SATA storage device by determining whether the storage device includes two ports (e.g., ports A and B). As shown in  FIGS. 4 and 5 , the SAS storage device  400  includes two ports (e.g., the ports  402  and  404 ), and the SATA storage device  500  includes one port (e.g., the port  502 ).  
         [0029]     In more detail, referring again to  FIG. 3 , the pull-up resistor and the voltage source  340  are coupled to the GND pin  332 . When a SATA storage device such as the SATA storage device  500  is coupled to the interface  300 , the GND pin  332  is uncoupled because the SATA storage device  500  does not have a port that is associated with the port  304 . Accordingly, in response to the GND pin  332  being uncoupled to a GND pin of a SAS storage device (e.g., the SAS storage device  400  of  FIG. 4 ), the GND pin  332 &#39;s signal is approximately the voltage (e.g., 5 volts) of the voltage source  340 . In such situation, the pull-up resistor “pulls’ the GND pin  332  signal up to the voltage supplied by the voltage source  340 . Also, such signal indicates a first logic (e.g., logic 1). Moreover, such signal indicates (e.g., to the logic device  342 ) that a storage device that is coupled to the interface  300  is a SATA storage device. The logic device  342  receives such signal of the GND pin  332 .  
         [0030]     Alternatively, in response to a SAS storage device, such as the SAS storage device  400 , being coupled to the interface  300 , the GND pin  332  is also coupled to the GND pin  432 . In such situation, the signal on the GND pin  332  is pulled down to 0 volts indicating a second logic signal (e.g., logic 0). Such signal indicates (e.g., to the logic device  342 ) that a storage device that is coupled to the interface  300  is a SAS storage device. The logic device  342  receives such signal of the GND pin  332 .  
         [0031]     Referring again to  FIG. 3 , the capacitor  338  is coupled to the detection circuit  334  (and the GND pin  332 ) so that there is a relatively low impendence alternating current (“AC”) return path to the GND pin  332 . Accordingly, the capacitor  338  reduces the detection circuit  334 &#39;s adverse effect on signal clarity of the interface  300 .  
         [0032]     Although illustrative embodiments have been shown and described, a wide range of modification, change and substitution is contemplated in the foregoing disclosure. Also, in some instances, some features of the embodiments may be employed without a corresponding use of other features. Accordingly, it is appropriate that the appended claims be constructed broadly and in manner consistent with the scope of the embodiments disclosed herein.