Supporting External Device Mechanism In Virtualize Desktop

As the IT constantly innovating, desktop virtualization has been popularized among people's daily life. Meanwhile, the peripherals, which locate in a virtualized environment, are also earning the heavy concern. For example, the local camera and printer, both of them are activated by using the USB ports of local client machine. Therefore, in the virtualized environment, how to seamless and on-demand use client peripheral devices, is a very meaningful research topic.This paper designs and implements a system, called SEDM (Supporting External De-vice Mechanism), to expand the local USB peripherals from local client to the remote serv-ers, by deploying of a virtual USB device driver. The function of this virtual device driver, like a repeater, is responsible for creating a one-to-one relationship between the real USB device on the client and the corresponding virtual device in the remote server. Furthermore, it also encapsulates the hardware commands as the IP packages and then transfers them into the desktop client via TCP/IP protocol. On the other hand, client installs a receiver, which is responsible for intercepting the data derived from the remote server, and then analyzing and relaying these data to the local real USB device. Besides, a device management is designed to maintain the relationship between the client and virtual server while coordinating the data send/receive to provide the communication between user and kernel space. The low-level control commands, issued by SEDM, are carried out by encapsulating the USB data request into IP package to transferring. This design can shied the difference between remote and local machine into the host controller layer. Once the virtualized desktop has emulated a virtual device with the real USB device, most applications and device driver can share this device in the remote server.The evaluation of SEDM System shows: SEDM system achieve the virtualization of USB flash disk and USB camera under different operating system environments , and USB flash disk copy data without too much delay, and USB camera get the images is basically real time. Performance tests show that in the LAN, copying data does not exceed the time delay of 60 seconds.