| With the rapid development of information technology, business running and academic research generate an increasing number of massive data. Storage Area Network (SAN) has become the best solution to the problems of storage bandwidth, capacity and management. SAN is an architecture to attach remote storage devices (such as disk arrays, tape libraries, and optical jukeboxes) to servers in such a way that the devices appear as locally attached to the operating system. FC SAN is the earliest-emerged and widest-adopted type of SAN, which is based on Fibre Channel technology. High efficiency, stability and security are the main advantages of FC SAN.FC HBA card is the necessary device accessing FC SAN. It is usually inserted in the PCI-X or PCI Express slot of a server's motherboard and offers physical connectivity between a server and a storage device. Fibre Channel Protocol (FCP) for SCSI is the essential protocol of HBA. It is located in FC-4 layer of Fibre Channel standards hierarchy and defines the mapping of SCSI over Fibre Channel.The purpose of this paper is to design and implement a HBA card. The focal and difficult point of the work is how to implement HBA card's key protocol, FCP in hardware and software, since the design would make a decisive impact on HBA card's I/O performance.The major work of this paper is to provide a solution of hardware-assisted FCP implementation, which leaves a large number of repetitive and simple FCP tasks with the hardware (such as the segmentation and assembly of SCSI data). The HBA driver no longer processed data in the unit of FC frame. It only needed to do management of exchanges in the beginning or at the end of I/O operation. This greatly reduced the number of interrupts and the burden of CPU. Xilinx FPGA development board (ml506) was used as development environment of hardware, and the FCP-assisted logic was designed in verilog HDL. Besides, the driver was developed in Redhat Linux of 2.6.18 kernel version. This paper first introduced the related protocols to FC HBA card (especially FCP protocol), including the FCP I/O operation procedure, FCP information units and so on. Secondly, it described the solution of hardware-assisted FCP implementation. Then it gave an overview of the interface between hardware and software, the functional division of hardware modules, structure and processing procedure of HBA driver. After that, the paper elaborated on each hardware module in detail, and described the key data structures and functions of software. At last, we set up the testing environment. Then this paper analyzed the test result and gave the direction of how to improve this system. |
