| With the development of Internet technology,personal computer applications and USB devices have become more and more popular in people’s daily lives.However,there is currently no support for network transmission between computer applications and USB devices,and it has not provided an effective sharing mechanism for external devices of computers.In order to meet the needs of users’ work sharing and improve the time and space utilization of devices,USB devices must break up the space limitations of personal computers so that they can be shared among different computers.At the same time,in 2015,several countries selected the "sharing economy" as the annual high-frequency words,it can be seen that the sharing model has become a common practice in the world.At this point,research and development of USB sharing system has a good practical significance.This article studies and develops a USB-based sharing system based on the Linux environment.Users can use the USB device on the serverunder any environment,just like using the USB connected to their own computer.The paper first introduces the related theories and technologies involved in the system implementation,such as USB communication,Linux device model,Linux file system,user space equipment management and other technologies.Then the technical requirement analysis of the whole system is carried out from the function and performance of the USB sharing system.According to the project,the hierarchical design of the USB sharing system was completed,including data transmission layer,network service layer and system application layer.Among them,the data transport layer data collects USB device date through the USB subsystem.Network service layer is responsible for receiving,handling and forwarding the USB data encapsulated into the IP packet.System application layer includes server and the client application,providing users with services such as device binding,device query,and device manning.At the same(?)module,and system application module.In order to improve the service side concurrent processing capability of sharing system data transmission,this paper designs and develops a data communication server with high concurrency based on the Poll mechanism,and designs the USBIPD listening daemon at the server peripheral and derives the child process to process concurrent requests,improving the service efficiency of the communication.In addition,in view of the actual situation of a large number of users request to shared equipment problems.The design has realized the communication server cluster structure mode and wireless communication mode,and use the heartbeat,address redirection technology such as improve the ability of the business services and the expansion of the cluster.Finally,according to the corresponding functional instructions designed by the system layer,the system is tested for functional applications,throughput,and transmission rate.The functional application test results and system communication test results of the system are obtained through experiments.This article based on the actual project,carried out the overall design of the USB sharing system,and the innovation and optimization of the four parts of the sharing mechanism of the USB device.First,Using automated mapping to share connections,users do not need to issue commands autonomously and device can be automatically mapped to the user’s client.Second,the network transmission protocol is designed to emulate the USB bus communication.Third,the problem that the shared port of the mobile phone equipment could not be identified has been solved.Fourth,the use of wireless communication networking mode optimizes the network environment between the server and the client network. |
