Electrical computers and digital data processing systems: input/ – Intrasystem connection – System configuring
Reexamination Certificate
2001-12-12
2003-07-29
Ray, Gopal C. (Department: 2181)
Electrical computers and digital data processing systems: input/
Intrasystem connection
System configuring
C710S008000, C713S100000
Reexamination Certificate
active
06601119
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a validation process involving a SCSI host and a SCSI target within computer environments, and, more particularly, to the use of computer-related processes resident at the host computer environment to modify the parameters and behavior of target devices in a SCSI environment.
2. Description of the Related Art
The capabilities of host computer environments have expanded significantly with the increased development of peripheral devices for attachment to the host computer. A variety of peripheral components are now available for use by the end user applications. For example, the peripheral environment may include external devices such as disk arrays, tapes, CD-ROMs, printers, network controllers, optical scanners, and various other apparatus that provide a wide range of functionality.
The external peripheral environment is typically connected to the host computer environment using a suitable bus architecture. The Small Computer System Interface (SCSI) technology is one example of such a bus topology. In a typical arrangement, the host computer is configured with a host adapter provided in the form of a SCSI controller to provide the proper interfacing between the host bus (such as PCI) and the SCSI environment. The host computer will also include suitable SCSI device drivers for the installed SCSI peripheral devices.
The SCSI communications protocol employs a transaction process between a SCSI device configured as an initiator and a SCSI device configured as a target. Any SCSI device can be equipped with both functionalities. The SCSI initiator originates a request for an action or task to be performed, while a SCSI target receives and performs the requested task as expressed in a suitable command structure. For this purpose, SCSI targets typically include an intelligent controller that enables it to perform the initiator-developed commands in a manner relatively independently of the initiator. A SCSI bus is used to transport data, command, and control information between the initiator and target.
One advantage of SCSI implementations is that the host CPU need not expend valuable processing cycles in monitoring and managing operations involving the SCSI target devices. For example, in a typical I/O request such as a read/write operation, a high-level user program simply generates the I/O request at the application layer. The operating system (OS) then forwards the request to the suitable host-based SCSI disk driver. This hand-off from the OS to the appropriate SCSI driver entry point typically represents the extent of the participation of the CPU in terms of fulfilling the request. The SCSI environment itself is configured to complete the operation without further intervention or assistance from the CPU.
For example, the SCSI disk driver translates the I/O request into a suitable SCSI command structure and forwards the SCSI commands to a SCSI host bus adapter (HBA). The SCSI HBA then forwards the commands to the specified SCSI target. Due to the intelligence of SCSI target devices, little intervention at this point is needed by the initiator to ensure completion of the I/O request. The target then completes the task as instructed.
In a host-based SCSI implementation, the host computer environment typically configures the SCSI host adapter as an initiator-type device, while the external components of the peripheral environment serve as target-type SCSI devices. For example, in a conventional computing environment, the SCSI initiator is provided in the form of a SCSI controller or SCSI host adapter resident on a host computer platform.
However, one persistent problem in SCSI-based systems involves the ability to seamlessly and readily integrate the multitude of peripheral devices into the host computer environment in a manner that avoids any compatibility problems. For example, due to the proliferation of peripheral devices from a vast number of OEMs (Original Equipment Manufacturers), system integrators typically face the problem of attempting to integrate external devices from a variety of vendors into the host computer environment. As a result, there typically is a behavioral variation between SCSI initiator and target operations that must be addressed before the system can be made fully functional.
The principal integration issue involves resolving the compatibility and interoperability problems concerning the relationship between the host-based SCSI initiator device and the external SCSI target device. In particular, it is necessary to ensure that the behavior of the various SCSI targets conforms to the operational expectations of the SCSI initiator. However, conventional strategies for suitably configuring the SCSI target are beset with difficulties because the approach usually involves piecemeal ad hoc solutions. For example, users typically need to interact repeatedly with both the SCSI initiator and target to facilitate the required configurations setup.
It is therefore seen that computer systems integrators must find appropriate solutions to readily configure SCSI target devices so as to ensure compatibility and interoperability with SCSI initiator devices. The ability of the SCSI initiator to access and intelligently communicate with any SCSI target device connected to the SCSI bus requires the target to exhibit a behavior compatible with the functioning of the SCSI initiator.
Typically, the target behavior requires adjustment, modification or other such alteration so as to place it in a condition that facilitates or enables access by the initiator. This behavior modification usually takes the form of reconfiguring the parameters that govern the behavioral aspects of the target. However, conventional approaches to such target reconfiguration lack uniformity and have proved unwieldy and cumbersome since the approach normally involves user intervention both at the host side and peripheral side.
For example, a user may need to interface with the peripheral device through a supplied control line if any such interaction is needed at the target side to manage aspects of the reconfiguration process. A user also may be required to manually alter various hardware-related settings in the target environment. This peripheral-side interaction also would be accompanied by user action taken at the host computer, such as executing a routine to pass command codes to the target.
SCSI commands are classified by the SCSI protocol as mandatory, optional, or vendor unique. However, in conventional schemes that do employ host-side command routines, attempts by the ordinary user to implement target reconfiguration typically do not employ vendor unique commands due to the level of expertise needed to understand and implement these commands. This limitation therefore affects the functionality and available number of operational configurations for the target.
What is therefore needed is a process that allows the host environment to fully configure the target device without any user intervention.
SUMMARY OF THE INVENTION
According to the present invention there is provided a method, apparatus, and computer program product for variously implementing a fully automatic reconfiguration feature capable of fully reconfiguring the behavior of a SCSI target device using a host system functionality. This functionality may employ suitable software, hardware, firmware, or any combination thereof. According to the invention, the validation process between the host (initiator) and target can be fully automated.
Generally, validation refers to the processes for verifying that a part or device works as expected. As used herein, according to one form of the invention, validation involves the use of suitable processes for determining that the peripheral SCSI devices connected to the host environment work in both the target and initiator mode. In particular, validation ensures compatibility and interoperability between the SCSI host adapter and SCSI peripheral device.
In one form, it may be considered that the validation routine
Gygi Carl E.
Paulsen Erik
Slutz Mark A.
LSI Logic Corporation
Maginot, Moore & Bowman LLP
Ray Gopal C.
LandOfFree
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